V is for Vitamin TRANSCRIPT

This is a transcript of the Gastropod episode V is for Vitamin, first released on April 11, 2017. It is provided as a courtesy and may contain errors.


CYNTHIA GRABER: Once I get that jingle stuck in my head, I can never get it out. Those of you who grew up in the U.S. will probably recognize it—that song is trying to make sure parents bought and gave us our daily…

NICOLA TWILLEY: Vitamins! And I’m sorry folks, I’m going to say it that way throughout. Even if our guest this week did make fun of me for it. Because that’s what we’re going to be talking about this episode: vitamins.

GRABER: Or vitamins. We’ll forgive you, Nicky, your native British pronunciation.

TWILLEY: Either way, we both need them. We all need them. But what are they?

GRABER: And how did we figure out what vitamins are, and why need them? That story involves chickens, doughnuts, and, yes, the Flintstones.

TWILLEY: Plus some news you can use: are we getting enough of them?

GRABER: All that and more this week on Gastropod, the podcast that looks at food through lens of science and history. I’m Cynthia Graber.

TWILLEY: And I’m Nicola Twilley. But first, we want to tell you about some of our sponsors this episode.


GRABER: But, before we get back to vitamins, we want to tell you about the survey that so many of you helped us out with. A huge thanks to all of you who filled it out—we exceeded our goal! You provided lots of super helpful information, and it’ll help us support the show and make it better.

TWILLEY: So we wanted to share some of the findings with you. Some of you asked for transcripts of episodes. Guys, we have those! They don’t go up right away, because they are created by our fabulous volunteer, Ari Lebowitz, but you will find them about two weeks after an episode goes out, at the bottom of that episode web page. Check ’em out.

GRABER: Next, lots of you wanted us to do more live events. The great news is, WE want to do more live events, too! But we need someone to invite us and pay to host the show. It can be a local science festival. Or a museum. Or maybe your company wants some live entertainment. Or you’re helping organize a conference and want to hire us to perform there. We would love to.

TWILLEY: We also heard from you that you want more episodes, like every week. Here’s why that’s not going happen, at least for now: I would die and Cynthia would too. You guys know it’s just the two of us—and the research and interviews and writing and mixing for this kind of show, it just takes time. Some of you seem to think we’re part of a network, like Radiotopia, but we’re not. We’re independent, so everything is on our plate and our plates are pretty full right now. Sorry.

GRABER: And now on to our ads. Some of you love how we script our ads—thanks! We try to keep them entertaining for you. Glad to know it’s working. But some of you weren’t crazy about having to listen to ads, especially if you support the show. So, to be transparent: so far, ads bring in about half of the budget that the show needs. That’ll grow as we get bigger, of course. But it’s just half. Our stretch goal is to raise another about 15 percent of our budget from donations. We’re not there yet. But of course we really appreciate everyone who’s already donated this year. And then, you know, we’re working hard to make up the rest from grants, live performances, and so on. So ads are here to stay. We need them. We hope you enjoy the quirky ads we—that is, Nicky, she’s the ad genius—that she writes for you.

TWILLEY: My own humble contribution. So, final couple of things we wanted to share. One, we found out that 20 percent of you—that’s 1 in 5 people listening right now—found out about this show from a friend. This was really really exciting. I mean, if all of you went and found one more person to share Gastropod with, we’d be well over our listener growth goal for the year. I would do a little dance.

GRABER: On video?

TWILLEY: No, the reward is you don’t have to see it. But, seriously, keep telling your friends. This is working! And then final thing for now: we have a new reward we want give you for supporting the show.

GRABER: We have really fun Gastropod stickers for you. They’re available if you give $1 per show or more on Patreon or a $20 or more donation on our website, Gastropod.com. And if you’ve already given and you want a sticker, email us at [email protected] Thanks again to all of you—we appreciate your feedback, your support, and of course, your listening!


GRABER: So, to help answer all our vitamin questions, we turned to an expert.

CATHERINE PRICE: My name is Catherine Price and my book is Vitamania: How Vitamins Revolutionized the Way We Think About Food.

TWILLEY: OK, we have our expert. Let’s start with something basic, like what is a vitamin.

GRABER: Except it’s not quite so basic.

PRICE: The tricky thing about providing a standard definition of a vitamin is that technically there really isn’t one. But, for the purposes of not totally confusing us right from the beginning, you can say that a vitamin is a substance that we need in very, very small amounts in order to prevent a particular deficiency disease and the substance is found in food.

GRABER: So, sticking with the basics, how many vitamins are there?

PRICE: So the the list of vitamins today would be A, B, C, D, E, and K. And there are eight B vitamins that go by other names like niacin or thiamin and riboflavin—things like that. But there’s 13 total human vitamins.

TWILLEY: These 13 vitamins—they are our cast of characters today. And really, they’re kind of VIPs. I mean, we would die without them, that’s how important they are.

PRICE: We need vitamins because they help make reactions happen. And they do so by helping to create or help facilitate these things called enzymes, which are large protein molecules that help chemical reactions speed up by multiples—I mean, up to millions, millions of times faster than they would on their own. And that keeps life going.

GRABER: Here are some of those chemical reactions we completely rely on vitamins in food to make happen: regulating our body temperature, excreting waste, synthesizing DNA, building and breaking down muscles and bones. Blood clotting. Energy production. The creation of the chemicals that allow our nerves to communicate—and that means they’re keeping our brain functioning.

TWILLEY: Basically everything. If all these reactions were left to run at their own speed, without enzymes, life would grind to a halt and we’d die. Enzymes speed them up, so that’s good. But the body needs vitamins to build these enzymes. So the next question is, where do we get these magical substances?

GRABER: We get almost all of these vitamins from plants. But why are plants making them in the first place?

PRICE: Obviously, plants don’t eat food. They get their energy from the sun and from water and they have chemical reactions called photosynthesis that creates energy that they can use to grow and store energy. So plants need vitamins to catalyze those reactions for themselves, just as we need vitamins to help with reactions in our own bodies.

TWILLEY: Plants are great at making useful chemicals and they can make all of the vitamins except for D and B12. Humans are not so good but we can make vitamin D, actually. Which is weird.

PRICE: Vitamin D is weird for many reasons, but that one, you know, we typically think of vitamins as things you need to get from food. But humans actually are totally capable of producing vitamin D in response to sunlight via a chemical reaction in our skin. And in fact that’s probably the way we were meant to get vitamin D because it exists in very very few animal products or food products at all.

GRABER: One of those 13 vitamins we need doesn’t come from plants or sunlight—we get it from meat. That’s B12. And actually, it’s in meat because it’s made by bacteria. All the B12 in the world is made by bacteria. The animals like cows and clams that we get it from, they absorb the B12 that the bacteria in their guts make.

TWILLEY: As it turns out, we humans also have vitamin B12-producing bacteria in our guts. But, sadly, they live in the end part of our guts, after the part of the intestine where B12 can actually be absorbed. There are a few other animals like us, including rabbits and gorillas. We’re called hindgut fermenters, technically. Anyway, rabbits get around this B12 problem by eating their own poo. Humans tend to get around it by eating animals. Or supplements.

GRABER: Good thing, too. So this is why for cows, B12 isn’t a vitamin, because their body makes it naturally from bacteria. A vitamin is something you have to get from eating food.

TWILLEY: Our distant, distant, distant ancestors—I’m talking single-celled organisms here—they could make all the chemicals they needed for metabolism. So there was no such thing as a vitamin for them.

GRABER: Over billions of years of evolution, and through the evolution of animals and plants, we—we eventual humans—we lost those abilities to make all those chemicals, because we can get them from our environment. Vitamin C is an interesting example.

PRICE: Scientists hypothesize that humans probably did have the capacity to make some of the substances we call vitamins in the past. And the one that’s usually brought up is vitamin C because we technically have the genes to create it but there’s a disabling mutation that makes us not be able to make it. And the general theory is that we may have evolved to not make our own vitamin C because we were surrounded by plentiful sources in nature, since vitamin C is contained in, you know, fruits and vegetables.

GRABER: All that vitamin C that we need from fruit and the vitamin B12 from meat in our diets—it’s all crucial to our survival. But even though we cannot live without them, the amount of each vitamin that we need to to power our bodies is vanishingly tiny.

PRICE: Vitamins are extremely, extremely hard to measure because they exist in minute quantities, like fractions of a salt crystal, for example. Crazy small.

TWILLEY: The amount of vitamins in foods is often so, so tiny that it can’t even be weighed. You have to figure out how much of the vitamin is there by how fast a bacteria that eats it grows. That’s how crazy small these amounts are.

PRICE: So that was another obstacle and challenge in the discovery of vitamins was that they really were essentially invisible.

GRABER: We take vitamins for granted, it’s hard to imagine that there was ever a time that we didn’t know about vitamins in our food. But they’re a really recent discovery.

TWILLEY: And the story of that discovery starts in Southeast Asia, in the 1800s.

PRICE: So in Southeast Asia, particularly in the mid to late 1800s, this mysterious disease started popping up called beriberi, and it involved nerve damage and then also cardiovascular issues and killed people also in grotesque, painful, and horrible ways, much like scurvy.

TWILLEY: Ironically, beriberi really only started being a huge problem thanks to technological innovation. That’s actually true of most vitamin deficiency diseases. Catherine mentioned scurvy—we covered that in our citrus episode. That’s a disease caused by a lack of vitamin C. Scurvy didn’t become a huge problem until better sailing and navigation technology meant that ships could be away from shore for months at a time and people weren’t eating fresh fruit and vegetables.

GRABER: In beriberi’s case, the disease only became a huge problem after the invention of better rice-milling technology.

PRICE: So this started to really become an issue after the invention of better rice-milling technology, meaning that technology that would automatically remove the rice husk and leave behind just the white rice that we typically eat today. So in cultures where rice was a main substance in the diet, there started to be this outburst of this mysterious and horrible disease.

GRABER: People in Asia are wondering: what is causing this horrible disease? At the same time as beriberi is exploding, in Europe, scientists are discovering that there are these tiny, microscopic creatures called germs that can cause diseases.

PRICE: And that caused a huge amount of confusion in terms of the search for the source and the cause of these deficiency diseases, because people started to look for a bacterial cause of things like beriberi and scurvy.

GRABER: Take a second here and think about this problem. To understand vitamin deficiency diseases, you have to understand that food contains vitamins—these are invisible substances that are essential to your health. Lots of people are trying to figure out what’s causing beriberi. Almost all of them are looking for a thing—a germ or an infection that causes the disease. They’re not looking for a thing that’s missing. There isn’t even the concept that this could be a problem.

TWILLEY: This is a recurring thread with vitamins. Until you have the idea of a deficiency disease, you can find the cure for the symptoms, but you won’t understand what’s actually going on.

GRABER: OK. Back to Southeast Asia in the late 1800s. Specifically Indonesia, which was a Dutch colony at the time. Lots and lots of people are dying of beriberi.

TWILLEY: And so the Dutch send over a doctor called Christiaan Eijkman to figure out what the hell up.

PRICE: And he comes over and he’s told to try to figure out what beriberi is and what causes it and how to cure it. And so his assumption is that there’s a bacteria. So he starts by getting a population of chickens, which he chose kind of randomly, and it happens to be very lucky that he did because chickens are one of the animals that are most prone to beriberi.

GRABER: Not all animals need to get thiamin in their diet, so not all animals suffer from beriberi. Chickens do. Not that Eijkman had any idea about any of this.

PRICE: So he picks chickens and then he divides them into two groups and he injects one group of chickens with blood from people who had beriberi to see, because that presumably would give them beriberi. So he sits back and watches and those chickens do start to get beriberi-like symptoms. But then he notices the control group is too, so that’s confusing. So then he says, OK, well, that maybe that’s because bacteria are transmitted by air and these chickens are too close, so we need to separate the populations and put them in separate cages in different rooms. So he tries various permutations of this. But the control group keeps getting sick. And then at some point, he does an experiment with the chickens in separate rooms and they don’t get sick. Neither group gets sick.

TWILLEY: What the what?

PRICE: And what’s more, the chickens that had been sick all get better. Which to me is just like, I mean, what would you do if you’re that researcher or you took I don’t know how much time infecting the chickens with supposed beriberi and it just goes away—like, it all just goes away? You start to think you’re delusional, like, did that really happen? And to his credit he didn’t just throw up his hands.

GRABER: Instead, Eijkman kept his scientific cool and tried to figure out what was different.

PRICE: And he happened to speak to this laboratory assistant who said, well, you know, in the beginning of the experiment the chickens were being fed rice but they were being fed a special kind of rice. They were getting the leftovers from people and the leftover rice was white rice. And then at some point, word got around that the chickens were getting this fancy rice, because that was a fancy, expensive kind. And they said you shouldn’t be giving that to lab chickens. Go back to the regular rice. So the chickens had been given regular rice, which was the kind that was brown and that still had a lot of its husk on it. And that happened to coincide with when the beriberi-like symptoms disappeared. So that gave Eickman the idea that, wait a second, maybe there’s something about the food that’s making a difference here.

TWILLEY: So now he needs to test this theory on humans. After all, he’s not even completely sure chicken beriberi is the same disease as human beri beri.

PRICE: And you can’t really ask the chicken the same diagnostic questions as people.

GRABER: It happens that Eijkman had a friend who ran a bunch of prisons, and they happened to serve the prisoners different kinds of rice. So he and his friend figured, let’s see what the rates of beriberi are in each prison and compare them to the type of rice the prisoners were eating.

TWILLEY: And basically the deal was in the prisons where men were getting just white rice, a quarter of the prisoners had beriberi, and in the other prison where it was brown rice on the menu, only 1 in 10,000 got the disease. So brown rice clearly had something that Eijkman called anti-beriberi factor.

PRICE: So you think, great. Like, he must be a Dutch hero. But, no, he didn’t get that response. He got mocked by his colleagues.They said, you know, I can’t believe it took six years to come up with such a stupid hypothesis, and, like, basically skewered him. Said that he must be suffering brain damage himself because of eating too much rice.

GRABER: His colleagues just couldn’t imagine that anything other than germs could cause disease. Eijkman had to be nuts.

TWILLEY: Eventually, Eijkman got a Nobel prize for his efforts, but it took a long, long time for people to accept that beri beri wasn’t caused by germs but instead by a nutritional deficiency. Eijkman’s anti-beriberi factor goes on to become the first vitamin ever found: thiamin.

GRABER: But finding and naming thiamin took another couple of decades. Thiamin was the first vitamin discovered, but for all of the vitamins, the discovery process took a long time.

PRICE: So it requires multiple steps of recognizing that such a thing exists, and then actually chemically isolating it. So, using tons—I believe it was literally tons of rice husks—to crystallize a tiny bit of thiamin so you can look at a substance and say that is thiamin or that is vitamin C. Then you need to understand the chemical structure of it, and then you need to be able to reverse engineer it, to be able to create it. And that last step, to give you a sense of how recent this all is, vitamin B12 was only figured it out in terms of actually its chemical structure in the 70s.

TWILLEY: So identifying and isolating vitamins actually took an extraordinarily long time, for each and every single one. But there’s something else kind of shocking about this whole thing, and that’s how recently the word vitamin was invented. It’s barely a hundred years old.

PRICE: The history of the word vitamin to me is one of the most fascinating things I found out when I was researching the book. Because when I started out I just thought that had been around since time immemorial and that—you know, it just seems so familiar. It’s like air, so how could that possibly be a new creation? So I was shocked when I found out that actually the word vitamin only dates to 1911. And when it came out people didn’t accept that as a word.

TWILLEY: The reason they didn’t accept vitamin as a word is that it was totally made up.

PRICE: And the story there is that there was a Polish biochemist named Casimir Funk. It’s a great name.

GRABER: Funk was studying beriberi. And, unlike everyone who was obsessed with germ theory, Casimir Funk—like Eijkman—he thought that beriberi was caused by a deficiency in some mysterious nutrient that nobody had found yet.

PRICE: So he went a step further than his colleagues though because he decided he was going to give it a name—give the substances a name. So he took the Latin word for life which is vita, and then he took the word amin or amine, which is the chemical structure that he thought that all these substances were going to share. And he mashed them together and he came up with vitamine, or vitamine—it probably was vitamine at that point. And it had an e at the end.

TWILLEY: Vitamine. Or vitamine. I kinda like it.

PRICE: So Casimir Funk loved his new word vitamine and he really wanted to get it into the public. But he was having trouble because his medical colleagues didn’t think that it was right to just make up a word and start dropping it into medical texts. And so in 1911, he tried and totally failed. It got cut. He had to refer to these things by a much more circuitous manner and it had some horribly boring title. But then in 1912, he figured out a way to get a paper published in a publication that didn’t require the approval of his superiors. And in that one he just started dropping vitamine, like, right and left. I think it appears 27 times in that paper. He just acted like, yeah, it’s a vitamine, like, what’s your problem?

GRABER: So Casimir Funk just threw that word vitamine around in his scientific paper. But it still took a while to catch on.

PRICE: The reason it wasn’t particularly popular in the beginning and it didn’t catch on is that, first of all, vitamin doesn’t refer to—there isn’t actually a technical definition, because as it turned out they’re not all amines and they’re lumped together more because of historical happenstance than they are because of anything chemical. So legitimately they probably shouldn’t be called vitamins. But his competitors’ suggestions were really bad. So there are things like anti-beriberi factor or food hormone or fat-soluble A, water-soluble B. I mean, just these things that were not catchy at all.

TWILLEY: Meanwhile, the general public is starting to hear about these magical new substances. And they like the sound of vitamines.

PRICE: By the early 1920s, you still have multiple words in use to describe the same substances. And the scientific community was having this big debate about, like, are we even going to keep this word because it’s ridiculous and stupid and we probably shouldn’t. But then they realized, well, people seem to be using it, so we better standardized this somehow. So one chemist suggested that they drop the final e because they weren’t all amines, so at least get rid of that controversy. And then he suggested putting the letters on them, because the main alternate way of referring to vitamines at that time was with this fat-soluble A, water-soluble B, water-soluble C terminology. And so that got smushed together and that is how we ended up with vitamin A, vitamin B, vitamin C, vitamin D, that we’re so familiar with today.

GRABER: So that’s the origin of the word itself. And then they’re named after letters of the alphabet. But there are multiple Bs, and a big gap between E and K.

TWILLEY: Did these scientists not know their alphabet? Or what?

PRICE: Vitamin B, interestingly, was originally thought of as one substance. And then scientists started to recognize it was actually eight separate substances. So that’s why we have B1, B2, B3. You may be saying, wait a second, we have a B12 but we don’t have—there’s only eight of them. How did that happen? And that speaks to the other thing that happened with vitamins is that some substances that people originally thought were vitamins turned out not to be vitamins at all. So those just got kind of thrown out. And there’s these gaps, like there’s no B 11, like these gaps in the terminology.

TWILLEY: And by the time this whole process is done and we finally know our vitamins, we enter a brave new world of vitamin donuts and sheep-wool processing factories in China. All still to come after we tell you about bras, bell peppers, and a couple of our sponsors this episode.


TWILLEY: So the other thing that is going on, while scientists are discovering vitamins and arguing about what to call them, is a much larger shift in how we understand and think about food.

PRICE: Another thing that needs to happen before you can conceive of a vitamin is that you need to understand that food can be broken down into parts.

GRABER: First, in the early 1800s, scientists discovered that food could be broken down into three major macronutrients. These are fat, protein, and carbohydrates. This is a big change in how people looked at their food.

TWILLEY: And then by the end of the 1800s, you get the concept of the calorie. We made an entire episode about the history and science of calories, which is truly bizarre—you should listen to that if you haven’t already. But the point is that scientists are measuring and analyzing food in completely new ways: grams of protein, numbers of calories…

GRABER: And now, in the early to mid 1900s, vitamins are the newest addition to the quantification of food.

TWILLEY: And this new mindset of thinking about food in terms of its parts, rather than as a whole—it starts trickling out of the lab and onto American plates.

PRICE: One of the people who was the biggest name associated with vitamins at that time was this guy named Elmer McCollum, who was a research scientist and he did a lot of work on vitamin A and vitamin D. Anyway, he also happened to write a nutritional and health column for McCall’s magazine, which was a woman’s magazine that was very popular at the time. And he was kind of like the Dr. Oz of the 1920s, where he was a respected, medical-seeming figure, and people really took his words seriously. So he started to write about vitamins.

GRABER: And Elmer McCollum—even though there wasn’t much science at the time about the amount of vitamins in food or how much we needed, the whole science of this was far too new—that didn’t stop Elmer. He put the fear of God in housewives.

PRICE: And he basically started to—I was going to say insinuate, but he pretty much said that if you’re not feeding your family, you, American housewife, reading this magazine and not feeding your family a well-balanced diet that has all of these vitamins in it, then you are going to cause your children to develop scurvy and be stupid and maybe blind and all these horrible things, and you’re basically going to cause disaster to fall upon your family. So it caused an awful lot of anxiety among the housewives and the readers.

TWILLEY: Suddenly housewives were supposed to somehow figure out—and remember there wouldn’t even have been nutrition labels on food at this point—I mean, this was just at the dawn of packaged and processed food anyway. But somehow these poor women are responsible for making sure their kids are getting enough vitamin B5, when still today no one knows exactly how much is enough of that.

PRICE: Forget the fact that you had been feeding your family before reading that article and they seemed just fine. You clearly are putting them at risk.

GRABER: Consumers are now worried about vitamins. So, at first, the early processed food companies were not into the whole vitamin thing. But then they saw an opportunity in the fear that Elmer inspired.

PRICE: And they suddenly realized that you’ve got these scientists saying that there are invisible, immeasurable substances in foods, with a catchy name, without which you’ll fall prey to these horrible deficiencies. And no one knows how much of these things you need and you can’t taste them. There’s no way to tell really how much is in the food. So they seize upon this as pretty much like the best nutritional marketing strategy ever, and the one that has really continued to inform the way foods are marketed today. And they start to use the existence of vitamins in their food as proof that the foods are not just healthy but also essential. So you end up seeing these very funny ads for things like canned pineapple, you know, that says, like, every meal should start with canned pineapple. And all these just kind of funny—to our eyes, really funny claims about vitamins.

GRABER: This is all going on before manufacturers could even add synthetic vitamins to foods. They’re just hawking what their food naturally contains.

PRICE: Synthetic vitamins began to come on the scene in the 20s and 30s as people began to figure out what their chemical structures were and then reverse engineer how you can make them. And they caught on pretty quickly. By the time of World War II they were—vitamin pills were widely available. There was a union that negotiated getting vitamin pills as part of its contract. You know, they had “V for victory” vitamin packs. It was definitely the beginning of the vitamin market that we know today.

TWILLEY: So now we have vitamin pills. But, at the same time, vitamins start showing up in processed foods. Food manufacturers add them to everything and anything and then they sell these fortified foods as healthy.


TWILLEY: My favorite example from Catherine’s book is Schlitz Sunshine Vitamin D Beer, which was launched in 1936 with the tagline: “Beer is good for you, Schlitz with Sunshine Vitamin D is extra good for you.”

PRICE: Or you have breakfast cereals, when the ability to add synthetic vitamins began to be developed—cereals with names like Vitamin Rain. It’s, like, rice shot from guns that has been treated with all these vitamins. And there actually was an attempt to brand vitamin donuts. If you Google the image for vitamin donuts, you’ll see this fantastic picture of these two angelic-looking school children gazing longingly at these donuts with vitamin donuts in big letters in the center. And they actually didn’t get approval for that thankfully. But you can still order prints of it and I have a poster of vitamin donuts in my kitchen.

GRABER: Vitamin Donuts aside, the truth is, the whole processed food industry and the new synthetic vitamin industry—they go hand in hand. You can’t have one without the other. In part, it’s because vitamins are super sensitive.

PRICE: Basically, you can destroy them all sorts of ways. So, by the time you get to the point that you’ve got refined flour that you’re going to use for a Twinkie, that flour does not have very many vitamins in it, and you have to add it back. You have to add vitamins back in.

TWILLEY: And food processing is hardcore—you’re stripping and centrifuging and bleaching and heating. I mean, like Catherine says, in the case of Rice Krispies, you’re literally firing the rice from a cannon to get it to puff up like that.

PRICE: A breakfast cereal is so processed that basically all of its vitamins are destroyed in the processing and then you have to add them back in, by baking them in or spraying them in afterwards to make it nutritionally excusable breakfast. Although, I’d argue no one should eat cereal. But, you know, it’s just kind of like a weird game of taking stuff out and putting it back in. And the question that I began to ask myself is, could we have developed the current food supply, and could we have developed our current food preferences, if it weren’t for synthetic vitamins?

GRABER: This seems like a crazy question, but let’s just go with it. Catherine figured out that in theory, when processed foods and synthetic vitamins were just starting to take over, America had enough vitamins in its food supply through just normal whole foods to feed its citizens. Of course it wasn’t evenly distributed and there was a lot of poverty and malnutrition. But, again, in theory, the American food supply contained enough vitamins to keep people healthy.

TWILLEY: Today, Catherine says, that is not the case, because of the proportion of our food that is processed. Without synthetic vitamins, scientists have calculated that 93 percent of us would be deficient in vitamin E, 88 percent in B9, 74 percent in vitamin A … you get the picture. Processing takes out the vitamin content of foods and most Americans eat a lot of processed foods. So where do those synthetic vitamins that we depend on come from?

PRICE: If you conclude that Americans are dependent on synthetic vitamins in their food supply, then you kind of hope that we make them here, because otherwise that seems like kind of a big vulnerability. If you want to have a crazy thought experiment: if you don’t make enough vitamins in America and whatever country it is that makes them cuts off the supply, then we’re kind of in trouble. Anyway, most of the vitamins are made in China. A lot in India. There’s some manufacturing facilities in Europe. But essentially none are made in the United States. And people often get confused because they think, oh well, there’s all these vitamin pills that are made in the United States. So plenty of pills are put together and formulated in the United States. But the actual raw ingredient, the actual vitamin C or the actual B12, is not made here.

GRABER: Yes, if China cut off our supply of synthetic vitamins, we would be screwed.

TWILLEY: So that’s pretty weird to think about. And how those vitamins are made is interesting too.

PRICE: Essentially, you start with ingredients that you never would think would create a vitamin, like a lot of things come from coal tar. And then you manipulate it chemically in various ways and you end up with vitamin C.

GRABER: Vitamin D is a particularly bizarre one. It links Australia and New Zealand to China and then to American cartons of milk and orange juice. Vitamin D is made from the lanolin, the oil in sheep’s wool.

CP2: So there’s this very interesting industry where lanolin is taken from New Zealand and Australian sheep, shipped to China, purified, irradiated, meaning exposed to ultraviolet radiation, and that prompts the chemical reaction, the same chemical reaction that happens in our bodies in response to sunlight, and creates vitamin D. And then you put into pills or you put it into milk or orange juice and that creates a main source of vitamin D for most people’s diets.

TWILLEY: The vitamin D in your milk or OJ comes from sheep’s wool. It really does.

GRABER: So now manufacturers are tossing synthetic vitamins into food right and left. You see added vitamins everywhere, not just in milk and orange juice and bread but in snacks and desserts and nearly every breakfast food. And then many people top that all off with a morning multivitamin. But how much of these substances do we actually need?

TWILLEY: Well, supposedly there is an answer to that in the form of RDAs. Recommended Dietary Allowances.

PRICE: The RDAs, or the recommended dietary allowances, are fascinating and really confusing. Like, they’re so familiar to us that you’d think that they should represent some true truth, you know, they should be like gospel truth. But the real story about dietary recommendations is that they, too, are a recent development. The first round of the recommended dietary allowances was issued in the 40s as a result of World War II. So there was a desire to try to figure out or quantify how much of the known vitamins people needed to function at their best.

TWILLEY: But what actually happened is that the guy in charge of figuring that out handed off the job to three female nutritionists who were at a conference with him. And he said he wanted them to figure it out by the next morning. Dick move.

PRICE: And so there are these great accounts written by one of the women that was basically, like, the men were off seeing the town and these women are, like, locked in a hotel room being, like, how are we supposed to determine the average person’s niacin requirements? You know, there’s like two experiments on it. Like, what the hell? So they basically came back and were like, we can’t do that, there’s no way to do that. And it became a much bigger project and it evolved into dietary standards and allowances. These were very deliberately chosen words because it worked in a margin of error. And the first ones were developed by basically taking the best guesses based on the evidence of the time and then adding a bunch to it to cover your bases.

GRABER: The science has evolved somewhat since then. But in many cases the standards we use today date to 1968.

TWILLEY: And the other thing is that RDAs are designed to meet the nutritional needs of 97-98 percent of people.

PRICE: What that really means is that most people don’t need that much. And the analogy I like to use with that is it’s like, it’s as if the government needed to knit a sweater in a size that would be big enough to fit ninety seven to ninety eight out of adult Americans. Most people are going to need a far smaller sweater than that.

GRABER: There are problems beyond the size of the sweater with the RDAs. Some vitamins can be stored in our body for a while. Vitamins A and D—we store those in our liver. It’s why you can soak up sun in the summer, create your own vitamin D, and have that vitamin D last throughout the darker winter months.

TWILLEY: And then let’s complicate this even more. Some people genetically have a more difficult time processing and storing certain vitamins.

GRABER: And then there’s our microbiome—all those bazillions of microbes in our guts. They actually create vitamins in our guts that we then absorb. And different people have different microbiomes. Scientists do not have a handle on this individual variation yet.

TWILLEY: So maybe you’re wondering sure, but, bottom line, what’s the harm in taking extra vitamins? More of a good thing has to be good, right?

GRABER: And why stop at a multi? Some people have thought that if if a small amount of vitamins keeps us alive, extra big doses are even better. They’ll cure diseases, like cancer.

PRICE: So things like vitamin C curing cancer, things like that—those not have been proven. And I’d also say that there have been a number of big studies done that seemed like they should have proven that megadoses of particular vitamins like beta carotene, the precursor to A, would have benefits and the opposite has happened

TWILLEY: This is still really cutting edge science. As Catherine pointed out, a couple of decades ago, a big study giving people megadoses of beta carotene to cure lung cancer was stopped when the people taking the megadoses were shown to be not only more likely to get cancer but also more likely to die of a heart attack. But on the other hand, earlier this month, a human trial of megadoses of vitamin C also to cure lung cancer—that was given the go-ahead after the doses were shown not to cause harm. So, basically, the science on megadoses is really not clear. But one thing is certain: more is not always better.

GRABER: But it’s not just that megadoses might be harmful—and they might be—but even regular supplementation? It might also have some unintended side effects. Vitamin B6, or niacin, is known to stimulate appetite. The government started adding niacin to flour in the 1940s. This was important because there actually was widespread niacin deficiency at the time, so that was solved. But researchers have pointed out that extra niacin consumption in our fortified foods—it also correlates with the time that America has gotten more obese. Obviously, a lot of things changed about the American diet at that time, and obviously obesity is super complex. But the point is, vitamins can be looked at like drugs. We don’t usually look at them that way, but they are powerful. And they can have side effects. We don’t know everything that they do in our bodies.

TWILLEY: Because with synthetic vitamins you can take too much—and you basically can’t if you’re just eating normal whole foods, because the quantity of vitamins in foods naturally is so tiny. But the other thing is, food contains hundreds and hundreds of other compounds as well as vitamins. Some we know have health benefits—things like polyphenols and lycopene in tomatoes. Some we don’t know yet, but they could be important.

PRICE: So the example that springs to mind is when I was looking into this company called Neutralite that creates these… they’re not really vitamins, they’re pills, they’re dietary supplements made from concentrated fruits and vegetables. And one of the guys was explaining to me that if you analyze what’s in an acerola cherry, which is a cherry that’s particularly high in vitamin C, you see these spikes for all of these different chemicals in that cherry. Like, there’s a big spike for vitamin C, but there’s all this other stuff, versus if you analyze a vitamin C tablet you’re just going to see a big spike for vitamin C and that’s it. And I asked him, well, what are all those other things that are in the cherry one? And he goes, we have no idea, you know. So I think I think that that speaks to the complexity and the danger of trying to oversimplify.

GRABER: And all these compounds work together in food in ways we don’t understand yet. In a study, rats that were given tomato powder did better than rats given just purified lycopene. There’s synergy in food that we’re still learning about.

PRICE: And, to me, the takeaway with vitamins was to use the historical story and how crazy that story seems to us, because, like, obviously there are vitamins, to then question as being too proud of ourselves in the present and thinking we have figured everything out. Because, you know, a hundred years ago people thought they’d figured everything out and they didn’t even know all the vitamins existed. So what do we not know?

TWILLEY: But here’s my question. Today, more than half of Americans take a dietary supplement of some sort—mostly a daily multivitamin. Should we be?

PRICE: The question of whether take a multivitamin is really common and seems really complicated. But I think you can break it down into some simple, maybe unexpected, questions. The first one is: what are you eating? Are you eating a diet that naturally contains foods that have lots of vitamins? Like, are you eating a wide variety of fruits and vegetables and minimally processed meat and dairy? Are you getting time in the sun so you can get vitamin D? Do you live in a latitude that allows that? Then you’re probably fine. I like to say if you’re eating like the cover of a Michael Pollan book, then you’re probably fine on vitamins. If not, I would suggest you change your eating habits, but you also could take a pill. If you’re eating the way a lot of Americans eat, where you’re eating processed foods that have vitamins added back in, you’re basically eating a whole multivitamin. So in terms of vitamins you’re fine. But you’re probably missing out on everything else that whole foods contain.

TWILLEY: I think a lot of people think of multivitamins as like a sensible insurance policy and a heck of a lot easier than changing their diet. But Catherine points out that pretty much all of the big medical organizations, from the American Heart Association to the American Academy of Family Physicians—they do not recommend that healthy people with no special issues take a vitamin supplement.

GRABER: That said, there are certainly cases where people do need supplementation. We’re definitely not saying that all synthetic vitamins are bad.

TWILLEY: And, of course, there are still deficiency diseases today. Catherine says an estimated 2 billion people around the world don’t have access to adequate vitamins in their diet.

GRABER: But, so, here in the U.S., if you do have access to plentiful fresh foods, you’re probably getting enough vitamins in your diet. You do not have to stress. Still, there are some interesting tips about how to get the most vitamins out of your food, and these tips also, in a happy coincidence, cut down on food waste.

PRICE: Some tips for how to get the most vitamins out of your plants have to do with why plants have vitamins which is basically to protect themselves against the sun. And once you think about it that way then all of the kind of rumors you’ve heard about how don’t throw away the peel of that apple, that has the vitamins—you realize it’s actually true. So outer leaves tend to have more vitamins. Produce that is darker tends to have more vitamins because dark colors absorbs more sunlight, which means there’s more radiation. So romaine lettuce is going to have more vitamins than iceberg lettuce.

GRABER: This is true even if the plant is underground—the outer edges tend to contain more vitamins. So don’t peel your carrots!

TWILLEY: Or your potatoes. Laziness rules.

GRABER: But here one thing that Catherine wants us to take away from her book: the vitamin industry and processed foods literally could not exist without each other. Vitamins enabled our processed food industry, and processed food gave synthetic vitamins a reason to exist.

TWILLEY: And that connection is dark, and it really reveals the dark side of vitamins. Yes, we need them. Yes, it is extremely fantastic not to suffer from scurvy. But the discovery of vitamins and the way that both scientists and food manufacturers talk about them has changed the way we think about food in really unhelpful ways.

GRABER: For one, it’s led us to think about food just as the sum of its parts. It’s reductive. It’s just like my grandma used to say to me when I was a kid, “Eat your potassium, drink your calcium,” instead of eat a banana and drink some milk. But bananas and milk are so much more than just those individual minerals.

TWILLEY: And thinking of food in that way also leads to this incredible arrogance of thinking we can reverse engineer it. The extreme example is Soylent, of course. Which I don’t really want to think about.

GRABER: Because it’s disgusting.

TWILLEY: It is. But the point is, there’s so much we still don’t know.

GRABER: This vitamin craze has also scared us. Elmer McCollum scared 1920s housewives, but we’re still scared today that we’re not going to get just what we need. And so we look for the latest food fad—yesterday, it was canned pineapple, or oat bran, today it’s juicing, or omega 3s, or wheat grass, or resveratrol from red wine. We’re looking for the next nutrient salvation. And we turn to the weirdest, unqualified gurus to help us out.

TWILLEY: Oh my God, don’t even start me. Gwyneth Paltrow selling vitamin C nanospheres and $90 doctor designed vitamin supplements that promise to help you lose weight, feel great and keep all those effing balls in the air. I am quoting GOOP.

GRABER: If we’re not being perfectly clear, we do not recommend Gwyneth’s GOOP vitamins.

TWILLEY: I mean, it’s just horseshit. But it’s incredibly powerful horseshit and a lot of us sort of want that silver bullet.

PRICE: And so that fear element of vitamins coupled with the hope that they contain, even in the word itself—like, vitamin is just such a hopeful word. The fear and hope really created much of our current attitude towards food, and then easily transferred over to where we are today with, like, hemp seeds are this miracle food, or chia. You know, there are these trendy foods that all of a sudden are made to seem like they can cure all ills. And it’s within the broader context of, if we don’t perfectly calculate our diet, something horrible is going to happen to us. So what I ended up concluding is that vitamins are really the beginning of nutritional faith in a way. We all want to have control over our health, we want to know what’s going to happen to us. We can’t actually do those things. But we can put our faith in something. And, as I concluded in the book, you know, in religion you put your faith in some sort of God. And I think that in nutrition we’ve put a lot of faith into vitamins.



GRABER: Thanks to Catherine Price, author of Vitamania: How Vitamins Revolutionized the Way We Think About Food. Catherine’s book contains many more fascinating stories, including much more about dietary supplements, and you should definitely read it. Links on our website, gastropod.com.

TWILLEY: And we’ll be back in two weeks, with an episode all about Japan’s national fungus. Can you guess what it is?

V is for Vitamin

They're added to breakfast cereal, bread, and even Pop-Tarts, giving the sweetest, most processed treats a halo of health. Most people pop an extra dose for good measure, perhaps washing it down with fortified milk. But what are vitamins—and how did their discovery make America's processed food revolution possible? On this episode of Gastropod, author Catherine Price helps us tell the story of vitamins, from Indonesian chickens to Gwyneth Paltrow. …More

TRANSCRIPT What’s CRISPR Doing in Our Food?

This is a transcript of the Gastropod episode, What’s CRISPR Doing in Our Food?, first released on October 7. It is provided as a courtesy and may contain errors.

NEWSCASTER 1: Cue the worldwide CRISPR frenzy! At the University of California, scientists used a form of CRISPR to edit mosquitoes so they can’t transmit malaria. Their colleagues are modifying rice to better withstand floods and drought.

NEWSCASTER 2: Scientists say it could someday eliminate inherited diseases like some cancers, hemophilia, and sickle cell anemia.

NEWSCASTER 3: Researchers in Massachusetts have created piglets that might one day provide livers, hearts, and other organs for humans. They used a gene editing technology called CRISPR to remove viruses from pigs that could cause diseases in humans.


SCIENTIST: This has CRISPR in it.

NEWSCASTER: So this is what’s revolutionizing science and biomedicine?

CYNTHIA GRABER: Wow, listening to that, it seems like scientists have discovered something that is going to change basically everything.

NICOLA TWILLEY: If you’ve been following the news at all, this whole CRISPR thing gets waved around like it’s literally a magic wand. But we at Gastropod are always a little suspicious of magic, especially when it comes to science—so we decided to get to the bottom of it.

GRABER: And find out what CRISPR means for the future of food. That’s right, this is Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber—

TWILLEY: And I’m Nicola Twilley. And this episode we are talking about CRISPR. Which I will say has a nice name, I like crispy things in general. But isn’t CRISPR just genetic engineering, like GMOs, with a shiny new rebrand for today?

GRABER: Right. How is it different from or the same as what scientists have already done to genetically modify foods? What is CRISPR?

TWILLEY: And will it really change what we eat? Or are we eating CRISPRed foods already and we just don’t know it.

GRABER: Should we be worried or excited? We promise you, when it comes to CRISPR and food, we’ve got it. Plus, the secret CRISPR in your yogurt.

TWILLEY: The yogurt story is the CRISPR story you won’t have heard anywhere else. And it involves microbes, so, you know, DRINK!


GRABER: So you’ve probably figured out that CRISPR is a gene-editing tool, but we wanted to learn what it is, and how it was discovered. This might sound a little strange, but trust us—to learn about CRISPR, we drove out to DuPont’s dairy culture plant and we met with a yogurt scientist named Dennis Romero.

DENNIS ROMERO: Okay, we’re in Madison, Wisconsin. It’s a kind of a dreary-but-sunny, if that makes sense, day. Winter’s coming. Anyway, we’re on the southeast side of the city, kind of on the corner. This used to be all farmland in the day but the plant which is just across the street was put up in the late 1960s, to make starter cultures.

TWILLEY: “Winter is coming,” I understand, but I don’t remember dairy starter cultures from Game of Thrones.

GRABER: You listeners know that cheese and yogurt is basically milk that’s gone bad, but in a good way. Bacteria have had their way with it. But when I leave milk in the fridge and the bacteria get going, it smells and tastes pretty gross.

ROMERO: Dairy cultures than would be bacteria that were originally found in the milk and over the years were selected and chosen. because they didn’t turn the milk that kind of a kind of funny sour nasty-tasting mess that you’d find, but they actually turned it into something quite pleasant like cheese and yogurt.

GRABER: In the past, someone might have made this discovery and then saved a little bit of the good yogurt to make the next batch. You can still do this today—take some yogurt you like and use it to make more yogurt.

TWILLEY: I have done this, in my one-and-only moderately successful attempt to make yogurt at home.

GRABER: But this is not what industrial yogurt makers do. They buy a package of just the right freeze-dried microbes from a dairy culture company—and DuPont is one of the biggest dairy culture companies in the world.

ROMERO: This red pouch one is called Yomix. It’s used to make any of a number of yogurts. And you just sprinkle this into the cheese milk or the yogurt milk in this case, and stir, and off it goes. It looks like a like a package of instant oatmeal, that’s about the size. And think about several billion bacteria in there that could turn, you know, many, many gallons of milk into yogurt.

TWILLEY: Dennis and his colleagues at DuPont have isolated and catalogued all the strains of all the bacteria that you might want to use to make yogurt. They know which strains of bacteria are the ones that will give you that nice, sour tang, and which make your yogurt more creamy, and which can help make it thicker or thinner.

ROMERO: In this catalogue, we’ve characterized these strains for these properties. And we give these recommendations to our sales people who talk with our customers, the cheese makers and yogurt makers, knowing what the bacteria or the culture can do, then they can recommend a specific culture to them to make what they’re looking for.

GRABER: All these bacteria that Dennis studies and that DuPont sells—they’ve been carefully selected to also be super fast and super reliable. The customers can make the same texture and taste of yogurt each time. This means the dairy culture business is big business.

ROMERO: Oh, how big? I don’t have the exact numbers. That’s something that I have no idea. I mean it’s hundreds of millions of dollars worth—even more I guess.

TWILLEY: But sometimes something bad happens at the yogurt factory. The company is using the cultures it bought from DuPont, but their yogurt is just not coming out right.

ROMERO: On occasion it can be kind of chunky and grainy looking. That’s probably a bacteriophage that attacked the fermentation at some point in time.

GRABER: This is the nemesis of yogurt culture bacteria. Bacteriophage are usually just known as phage, and a phage is a tiny, tiny virus that attacks bacteria.

TWILLEY: You think microbes are small and everywhere, but phage are even smaller, and even more ubiquitous. There are more phage on earth than every other organism, including bacteria, put together. And phage cause a trillion, trillion infections in bacteria every second.

ROMERO: That’s the one thing that will disrupt the cheese maker or yogurt manufacturers’ process more than anything else. You know, if you ever catch the flu, you don’t feel too good. You’re kind of slow, you’re kind of sluggish. Well, the bacteria if they catch the flu, they can feel that way. Worse yet, they tend to explode. So, not a good thing.

TWILLEY: Sometimes my head feels like it’s going to explode when I catch the flu. But actually exploding is a whole other level of bad.

GRABER: Dennis took us into his lab and introduced us to Annie Millen, a scientist with his group, and she showed us a clear circle of agar gel on a petri plate. They’d grown yogurt bacteria on the gel, and then infected the bacteria with phage.

ANNIE MILLEN: This phage is pretty deadly. So on this one, there’s still the hazy bacterial lawn in the background. But there are really large circular zones of death where it’s just clear.That’s all where the bacteria has died, and it just looks like nothing. because there’s nothing there anymore.

ROMERO: Can you hear the bacteria? “Ahh, I’m popping, I’m bursting.”

GRABER: Obviously, it’s not a great thing when your yogurt-making bacteria explode, because they’re no longer making your yogurt.

TWILLEY: In the past, when a yogurt company would call Dennis and say “Oh no, our starter cultures aren’t working and the microbes are all exploding”—the first thing Dennis would suggest was that they clean the entire factory from top to bottom.

GRABER: Because Dennis wants the yogurt maker to try to get rid of the phage. Though of course that’s pretty tough given how tiny and plentiful they are.

TWILLEY: And then Dennis would give them a new set of cultures. But they weren’t the same strain—he’d deliberately give them different strains of bacteria that could make the same yogurt, but that might be tougher than the microbes that exploded.

ROMERO: One of the unique things about them is that they have different sensitivities to these bacteriophages. And just like human beings, you know, Nicky could catch the flu. But, Cynthia, you could be sitting right next to her but you’d be perfectly fine because you are immune to whatever she’s got. And the bacteria kind of behave the same way. The key point here is you have to find two strains that will do the same thing except for their sensitivity to a given bacteriophage.

GRABER: Okay. So this is what’s been going on for a really long time in the yogurt business. Phage kill your batch of yogurt, you buy a new strain of yogurt culture, and so on. But then, a few years ago, something really exciting happened.

ROMERO: For me, this is actually kind of an interesting story of how science actually happens. I mean it’s not something that you plan for, you know, and say today I’m going to discover CRISPR. I wish I could have said that but, no, that’s not really the way it happened

TWILLEY: The context here is that it was the early 2000s, and genetic sequencing had got faster and cheaper and so DuPont decided to sequence some of their key yogurt bacteria.

ROMERO: We were looking for a way to identify our different strains in a very quick and rapid way. Because, you know, they don’t sit there and go “Hi, I’m Bob,” ‘Hi, I’m Steve,” whatever. And so there’s a lot of work that has to go on to determine, yes, this is strain one, strain two, strain three.

GRABER: And in doing these genetic sequences to try to identify their dairy culture bacteria, Dennis and his colleagues noticed these kind of weird stretches of DNA, a whole bunch of them. Nobody really knew what they were, but they’d been observed before, and so people called them this complicated name: Clustered Regularly Interspaced Short Palindromic Repeats. CRISPR.

ROMERO: It was a very short repeated sequence, of the same sequence repeated over and over and over again, with something that was seemingly nonsensical stuck in the middle of each of these little repeats.

TWILLEY: Like everyone, Dennis and his colleagues had no idea what these nonsensical CRISPR sequences did. But they realized they might make for a good fingerprint.

ROMERO: So we started to sequence more of them and, oh, look, you know, there’s something interesting. There’s subtle differences between them. That little piece of nonsensical DNA—you can line these up, because some of the strains have the same ones. And then at some point they start having different ones.

GRABER: At the time Dennis and his colleagues had another research project going on. They were taking cultures of yogurt that had gotten sick from phage, and they’d see if any of the bacteria lived through the infection. And some always did.

TWILLEY: So they took a look at these survivors—the phage-resistant bacteria—and they noticed a difference in the CRISPR section of their genome.

ROMERO: On one end, the phage-resistant variant had a couple extra pieces inserted in there. And I think it was that moment where, like, for any scientist there was like the, “Aha!”

GRABER: The aha was the idea that this tiny bit of code, the part that they had no clue what it did—this might be the part that made the bacteria able to survive an attack from that particular phage.

ROMERO: And my first thought was, can it be that simple? Think about this bacteria having 2 million base pairs that tell it what to do how to live and how to work. That two little pieces of DNA, about 30 nucleotides or 30 letters stuck in the correct place, can actually confer the ability of this bacterium to resist a bacteriophage, so it lives.

TWILLEY: This is Dennis and his colleagues’ breakthrough. They are the ones who figured out that maybe these CRISPR sequences in bacteria that no one understands what they do—maybe they’re to do with immunity to phage.

GRABER: So then the first order of business to test this idea is to figure out where the sequences come from.

ROMERO: So when we took a look, the only difference that we could tell, at least from what we were looking at, was: the sequences in the CRISPR array came from the bacteriophage. Oh, that’s interesting.

TWILLEY: Those nonsensical repeats in the bacteria’s genome? They were little chunks of phage DNA.

GRABER: To test whether the phage DNA is what helps with immunity, they did an experiment to try to figure out if the bacteria that survive a phage attack have bits of code that match to that exact phage.

ROMERO: So it’s really, really simple. You take the bacteriophage, you mix it with the bacteria, and then you throw it on this agar nutrient plate and see what lives. And you take what lives. And we look at the CRISPR loci—and oh look, it’s got a couple, one or two extra spacers in it again. And you look at the spacers and they come from the bacteriophage. So now you have this—hey, the two are connected in some way shape or form.

GRABER: So basically, somehow, it seems like that tiny bit of phage DNA gets into the bacteria, and the bacteria then become immune to that phage.

TWILLEY: Which is extremely exciting. Dennis’s next experiment was designed to confirm that that is really what’s going with CRISPR. If he inserted a little piece of phage DNA—one of those little CRISPR sequences—into a yogurt-making bacteria that was not immune to that particular phage, would that bacteria become immune?

ROMERO: And surprise, surprise—well, maybe not a big surprise. Yes, it was. Oh, okay. So now it’s absolutely clear: without ever having seen the bacteriophage, we can provide this immunity, this resistance to it.

GRABER: The way that this happens out in the real world is: some of the yogurt-making bacteria survive a phage attack. And the ones that survive keep a little mug shot of the evil phage that tried to kill them. In this case, the mugshot is a snippet of phage DNA.

TWILLEY: The survivor bacteria hold onto this mugshot in case they ever meet that evil phage again. And they stick in their DNA, for safekeeping, right next to where they keep their phage-killing weaponry.

GRABER: And one of those weapons? It’s a tiny protein called Cas9—CRISPR-associated protein number 9. And what this tiny little protein does is it snips. It’s basically a pair of scissors that just slices straight through phage DNA.

TWILLEY: And when your DNA gets sliced, you don’t really work as well. In fact, you are often toast, especially if you are a phage.

GRABER: The whole system together is super cool: mugshot plus scissors equals immune system.

ROMERO: People have described the CRISPR array as being something like memory for the bacteria. And it really is because it’s a memory of what viruses, in this particular case, what phages that they’ve been exposed to. So that in the future should the daughter cells of that CRISPR-ized—that’s what we call it—bacterium meets that phage again, it knows what to do to protect itself.

TWILLEY: This system is actually found in a lot of bacteria, although not all. It’s not unique to dairy cultures though, but, because we love yogurt and cheese and the microbes that make them so much, that’s where we first noticed it

GRABER: Dennis had been looking for a way to fingerprint his bacteria strains, but this—this was something else altogether.

TWILLEY: This was transformational. Dennis could use this natural bacterial immune system, CRISPR, to cure his customer’s sick dairy cultures.

ROMERO: So, cool. This makes life easy for us. So we go through the process of vaccinating or immunizing the bacteria, and then putting them back out there in situations where we know there’s a bacteriophage present, and they perform perfectly fine. It makes life much more simple for us and we can go off and study other things. It sounds ridiculously simple when I put it that way, but that’s what it does.

TWILLEY: Within a year, Dennis and DuPont were immunizing all their starter cultures and selling these CRISPRized microbes to their customers.

ROMERO: Essentially, it’s pretty much just like the flu vaccine. You try to find the most prevalent ones that are impacting the industry at that time.

GRABER: And any time there’s a new phage that appears, they can add that mug shot to the bacteria’s collection, too.

ROMERO: So, in essence—we joke about this—but from the perspective of sensitivity to a bacteriophage, we can immortalize that particular strain.

TWILLEY: Dennis and his team just keep adding new mugshots.

ROMERO: There’s no limit that we found just yet to how many spacers it can acquire. So it just goes on and on and on.

TWILLEY: For the past fifteen years, almost all commercial, industrial-type yogurt—which is basically all the yogurt in the supermarket—has contained CRISPRized bacteria.

ROMERO: We tell this to people. You’ve been eating CRISPRized cultures forever—you just didn’t realize it.

TWILLEY: This is something you never hear in all the hype about CRISPR. We’re already eating it all the time, thanks to the microbes in our dairy.

GRABER: These CRISPRized cultures are totally standard in the dairy industry these days. The yogurt companies are thrilled, DuPont is thrilled, Dennis and his colleagues are thrilled. The yogurt is a better, more consistent texture, they don’t have to add any extra thickeners in case the microbes are falling down on the job, they don’t have to rotate strains of microbes, it’s great.

ROMERO: Yeah, you know, it’s a living system. And one’s ability to control it to some degree so that you get the same thing out every day is a big deal.

TWILLEY: A couple of key words here are ‘living system’ and ‘to some degree.’ We’re talking about biology, so, of course, it’s not 100 percent under human control and the same every time. For one, not all yogurt bacteria even have this kind of immune system, so they can’t be vaccinated against phage. Also, some phage can evolve to beat CRISPR or work around it. But, still.

GRABER: Yeah, still. It’s changed the yogurt business.

TWILLEY: And honestly, that’s kind of the least of it.

GRABER: Right, as you heard at the beginning of the show, CRISPR is actually changing the world. We asked Dennis if he and his colleagues had any idea when they discovered this system what other researchers might end up doing with it.

ROMERO: We joke amongst ourselves that one of the first exercises was we wrote down all these experiments and possible applications and things. And we really went to town with that. What could you imagine that this could be useful for?

TWILLEY: The way Dennis and his colleagues saw CRISPR was as a way to create immunity. So in their brainstorming session, they came up with lots of cool ideas—outside of the yogurt business—where immunity would be useful.

ROMERO: So one of the things I thought was really, really interesting and gratifying for me personally was we had written down: would this be something that could somehow be adapted to confer immunity to things like influenza or HIV?

TWILLEY: Scientists are currently doing exactly that—there’s brand new research using CRISPR as a tool to cure HIV and the early results seem promising.

GRABER: But the part Dennis and his team didn’t predict is that CRISPR would become a tool for editing nearly everything. And that’s exactly what’s happened.

ROMERO: I’m still kind of awestruck by it all because, at least for me, I just—I find this fun. And to be able to come across something like CRISPR-Cas and see the impact that it’s having on life and people in general? I sit there and I think about it and go, wow, I had something to do with that. I mean, how lucky can one be?

GRABER: That’s kind of every scientist’s dream, to see research they’ve been a part of having such a major impact.

TWILLEY: But all this came out of something super non-world-changing—yogurt. No offense to yogurt, which I love, but you know what I mean. So how did CRISPR make it out of the yogurt factory and into nearly every genetics lab in the world?

GRABER: That’s just what what we’re going to reveal next.


GRABER: To answer the question of how CRISPR became the hottest new thing in genetic engineering, we need to take a step back.

JENNIFER KUZMA: Right. Well, since about the mid-1980s, we’ve been genetically engineering plants.

TWILLEY: Jennifer Kuzma is a trained biochemist who co-directs the Genetic Engineering and Society Center at North Carolina State University. And she told us that back in the 80s, before CRISPR, scientists had a couple of ways to insert new genes into plants—but they had no control over where that new gene ended up in the plant genome.

KUZMA: Like, you take a gene from, for example, a fish—and it would land anywhere into the crop that you wanted to place it in, let’s say tomatoes.

GRABER: This very example that Jennifer is using, this is one of the most famous early examples of genetic engineering. The idea was that this cold-water fish called the winter flounder had an antifreeze gene that helped it survive icy temperatures, and this gene could help tomatoes survive frost.

TWILLEY: So scientists put the antifreeze gene in the tomato. And then a bunch of people freaked out about the resulting fish-tomato.

PROTEST CHANT ON NEWSREEL: Hey hey, ho ho, GMOs have got to go!

NEWSCASTER: These protesters want this grocery chain and others to stop carrying foods with genetically-modified ingredients.

PROTEST CHANT ON NEWSREEL: Careful what you put on your grocery shelf!

NEWSCASTER: This man’s costume is meant to illustrate genetically-altered fruit that’s been given fish genes to make it hardier in cold weather. They call it Frankenfood, and they say it’s bad for people, bad for the environment.

TWILLEY: As it turns out, the fish-tomato didn’t do so well in field trials either, so it never made it to market. But that didn’t stop companies from creating all sorts of other GMOs. You’ll maybe have heard of Golden Rice, the rice with extra vitamin A—that comes from scientists inserting a daffodil gene and a gene from a soil bacterium in ordinary rice. There’s also pink pineapples and faster-growing salmon and non-browning apples, all with genes borrowed from different species. You can’t buy all of these yet, but they’re all approved for sale, at least under U.S. regulations.

GRABER: But, really, until now, most of the research on genetically modified foods has been focused on making plants resistant to certain weed killers. That meant that farmers could use those herbicides in the field, the chemicals would kill all the unwelcome plants, but the crops would still be going strong because they were resistant to that weed killer. So you have GM herbicide resistant corn, wheat, soy—and these are all being sold and used today, and if you eat processed foods in America, you are eating these GM crops.

TWILLEY: That might come as a shock to you. Especially because there’s still a lot of public discussion about whether genetically modified crops are really safe—safe for the environment, safe for human health. In the European Union, they’re mostly banned.

KUZMA: Genetic engineering has a pretty rough history when it comes to foods and there’s been quite a bit of controversy over genetically modified foods and whether or not they should be labeled and people seeking to avoid them through buying organic or non-GM products.

GRABER: Proving something is safe in terms of our health is really hard, but so far none of the studies have shown that these GM crops are bad for us. Whether their main use—making crops resistant to weed killers—is an overall win for growers and for the environment or not, is definitely questionable.

TWILLEY: That’s been the story of genetically modified crops up till now. But today, GMOs are sort of old school. The cool kids are all using CRISPR to create new crops. It evolved in microbes, and Dennis and his colleagues still use it in yogurt cultures. But it turns out that, with a little bit of tweaking, the CRISPR-Cas9 system can be used in all sorts of living things.

GRABER: As Dennis explained, there are two parts to CRISPR. There’s a piece that slices, that’s Cas9, and then there’s a piece that recognizes phage DNA, that’s CRISPR. But imagine this—you could put a different piece of plant or animal genetic code instead of phage DNA next to those scissors. Now you can direct the scissors to cut a very precise piece of DNA in, say, a tomato.

YIPING QI: And then you allow the sort of error-prone DNA repair pathway to repair the broken DNA. The result in most cases is a gene knockout

GRABER: Yiping Qi is a genetics researcher at the University of Maryland.

TWILLEY: And this process Yiping’s describing, works like this: instead of hunting down phage and slicing them to death, this tweaked CRISPR-Cas9 system will hunt down the DNA sequence of your choice, and slice it. The sliced DNA tries to repair itself, but usually there’s a kind of scar, where it was sliced, and the gene at that point, where the scar is, doesn’t work anymore. And there you go. You’ve knocked out a gene from the tomato’s DNA—the exact gene you wanted to get rid of. And, unlike the old-school fish tomato style GMOs, you’re not adding any new genes.

GRABER: Dennis and his colleagues figured out how bacteria use this slicing system to kill phage in the mid-2000s, and they published papers on it in 2007. About five years later, two different groups of scientists both claimed to have been the ones to figure out how to use this CRISPR system to edit something other than yogurt-making bacteria—and they’re fighting about it in court. Because it seems so flexible and so useful in genetics and human health, and all of this promises to bring in so much money—it’s a huge patent battle.

TWILLEY: But what do we care about here at Gastropod? Obviously, our friends, family, world peace, but, you know, mostly food! And CRISPR is set to transform our crops, too.

QI: I mean that CRISPR has been really put in to many, many crops. Almost nearly all the crop plants which you can transform, such as the wheat, maize, and sugar cane, and tomato. Many, many—like even carrots, which I have worked with a collaborator.

GRABER: This is a different technique, and it’s being used in a different way.

KUZMA:  With transgenic technology, it was very costly to bring a crop to market. Very costly to engineer it. With CRISPR technology, we’re seeing a wider variety of products. So not only, you know, your commodity crops like corn and soybeans and cotton but more minor vegetable and fruit crops.

TWILLEY: Including ones that are so minor that you may not have even heard of them. We’re talking about crops that don’t necessarily even make it to the store right now.

JOYCE VAN ECK: So they’re referred to as either underutilized or orphan crops.

TWILLEY: This is where we’re going next. To the crop orphanage, where some of the most minor fruits and vegetables of all are about to be rescued thanks to the magic of CRISPR!

VAN ECK: Yeah, these orphan crops out there, without anyone to care for them. LAUGHS

TWILLEY: And we’re going to visit the orphans with Joyce Van Eck. She’s a bio-engineer at Cornell.

GRABER: Though she’s laughing, Joyce does care about them. These crops are orphans because they’re not the type of plants we grow in a big monoculture. They’re tough to grow on a large scale, so they’re not traded internationally, and they don’t get a lot of research love.

TWILLEY: Joyce has picked out a particular orphan to adopt. It’s called the ground cherry, and it comes from the same family as peppers and tomatoes. It’s like the underachieving, less loved sibling.

VAN ECK: It’s this cute little yellow fruit that is surrounded by a husk. It’s kind of like, if you think of a little fruit in a balloon. And it’s related to tomatillos. If you’re familiar with tomatillo, it looks like a tomatillo. But it’s much smaller and it’s yellow. And it’s got—tomatillo is a tart flavor, but ground cherry has a sweeter flavor.

GRABER: When I had a ground cherry for the first time, about a decade ago, I totally freaked out in surprise and delight. They’re sweet and addictive, and I get so excited when I see them for a few weeks a year at the farmers market. But they’re expensive, and they’re not around for long. Because, like other orphan plants, they’re kind of a pain to grow.

VAN ECK: The plants are very… have this wild growth habit. They grow very large and they’re unmanageable. And also they’re called ground cherry because the fruit drops to the ground. Which you can imagine makes it very difficult for harvesting if you were, say, in a larger agricultural production setting.

TWILLEY: Funnily enough, ground cherry’s rockstar cousin, the tomato, also had many of these annoying characteristics back in the day. But over the course of time, humans bred those out.

GRABER: And then geneticists like Joyce figured out what genes in the tomato had changed over domestication to make the tomato more user-friendly. You know, the fruit grew more orderly on the vine, it didn’t drop on the ground, it was the right size.

VAN ECK: We decided to look for a plant species that was more distantly related from tomato but also was underutilized and had very little domestication or crop improvement effort. And that happened to be the ground cherry.

TWILLEY: Could Joyce and her colleagues use CRISPR to deliberately make a change in the ground cherry that had been just a lucky mutation that humans noticed and then kept breeding into the tomato?

GRABER: Take the out-of-control growth of the ground cherry. Joyce knew just what gene should in theory turn that off. When this gene is working, like in the ground cherry, plants just grow wild. But if that gene gets harmed when the CRISPR system slashes at it, then the plants should be much more compact.

TWILLEY: So Joyce built a little CRISPR set-up to target the ground cherry version of the gene that she knew turned off the wild growth in tomatoes. And she put that CRISPR system in some ground cherries. And, hey presto, her new look, CRISPRerized ground cherry was the opposite of its old, spidery, long-trailing self. The DNA that coded for that kind of unmanageable growth was gone, and so the plant now… self-prunes.

VAN ECK: Oh, it was—it was dramatic. It was a huge difference in what we were seeing. We went from plants that were, I’d say, five feet tall for the non-CRISPR, non-edited lines at maturity, to plants that were maybe two feet tall.

GRABER: Now, if plant breeders wanted to breed this type of self-pruning trait into a ground cherry the traditional way, they’d find a ground cherry plant that happened to be small and compact but maybe it didn’t taste as sweet, and they’d breed it with a sweeter one, and then grow the new plants out, then find out which offspring was both sweet and self-pruning, and they might have to do that a bunch of times.

TWILLEY: And if they were very, very, very lucky, they’d end up with a ground cherry that was everything they wanted. But they might retire first.

VAN ECK: Yeah. So it would take definitely more than 10 years to be able to do that type of work.

GRABER: But CRISPR is dramatically faster, and more targeted. It took Joyce and her colleagues only two years to get self-pruning ground cherries.

VAN ECK: So our work with the CRISPR is taking this angle where we’re using CRISPR to fast-track domestication, fast-track improvement.

GRABER: This was an amazing improvement, but it’s not enough yet. Joyce has spoken to local farmers around Cornell, and they say there’s a bunch of other changes that would help ground cherries go mainstream.

VAN ECK: We have a long wish list.

GRABER: It’s possible that for some of the items on Joyce’s wish list—things like fruit size, or whether the fruit drops on the ground before it ripens—if Joyce wants to change these, it might not be as easy as just targeting one gene. Genes often aren’t direct codes, one gene does one thing. It often takes multiple genes that work together to create something like drought-resistance or flavor.

TWILLEY: In its native bacteria, CRISPR usually goes after one thing at a time. But scientists have taken the CRISPR system and tweaked it so it can go find and slice multiple different things simultaneously. That means that Joyce could potentially design one CRISPR system that would target all the however many genes she needs to target in ground cherry to deal with its fruit drop problem.

GRABER: Or you could use CRISPR to target lots of different genes that change different traits all at the same time. This is a pretty new and super useful development— Yiping Qi has just successfully tried it in rice.

QI: We simultaneously targeted three genes and focusing on the trait which is about seeds. So we were able to enhance the number of seeds produced per plant and also how big the seed is, you know, per grain. So putting them together, sort of targeting them together, we were able to drastically enhance the yield.

TWILLEY: The main thing that makes CRISPR so useful for these kinds of edits is how precise it is. In a lot of crops, a piece of DNA that affects yield might be pretty tightly connected to, say, the DNA for a certain kind of disease resistance. In normal breeding, you can’t break that link—which means you can’t disconnect one trait from the other. But Jennifer says that CRISPR is kind of like a scalpel—it can get in there and separate even tightly connected genes.

KUZMA: With CRISPR, we can go in and we can make very precise, targeted changes at particular locations in the DNA. So it’s kind of like taking paper to pen like you would edit a book. You can go in and you can edit the letters in a word or you can change different phrases or you can edit whole paragraphs with CRISPR technology at very specific locations.

GRABER: We should say, none of these CRISPRed crops are available in stores yet, but some are pretty close. CRISPR is fast, it’s inexpensive, it’s precise, scientists love it, breeders love it. I mean, what’s not to love?

TWILLEY: I’m so glad you asked Cynthia, because I am falling head over heels for this CRISPR magic. But then, my cynical bitter side is saying—hey, there must be a downside. And my cynical bitter side will be right back to talk about that after we tell you about one more sponsor this episode.


GRABER: So—downsides. A couple of years ago, scientists were super excited about a gene-edited cow.

NEWSREEL: This is Brie. He might look like any other cow, but there’s one little thing about him that sets him apart from his breed. Brie has never grown a pair of horns. And that wasn’t a fluke of nature.

GRABER: Brie the cow wasn’t edited using CRISPR, but using a similar set of genetic scissors from bacteria. Scientists used these scissors to create a cow that wouldn’t grow any horns, so the animals couldn’t gore farmers or other animals.

TWILLEY: Normally, a cow’s horns have to be removed by hand, which some people say is painful for the animal. So this genetic edit was pretty cool. Except that it turned out that the edit was not quite as precise as the scientists had hoped.

GRABER: Two things happened. First, a bit of that foreign bacterial DNA was left in the animal—it was supposed to have been removed entirely.

TWILLEY: That’s a problem because now the hornless cow has got a little bit of alien DNA inserted in it. So rather than being one of these new school gene-edited organisms, it’s more like an old school GMO, like the fish tomato.

GRABER: And second, there was an accidental bit of DNA that also got inserted, and this one seems to have to do with antibiotic resistance. So like maybe if the animal got sick, antibiotics wouldn’t work as well. That’s pretty bad.

TWILLEY: So long story short, yes, these new gene editing techniques, including CRISPR, they are super precise, but they’re still not 100% precise. That antibiotic resistance—scientists call that kind of unwanted extra edit an “off-target effect.” Doing your edits with CRISPR should lead to way fewer off-target effects than the old-school, blast-your-gene-into-the-DNA method. But there could still be some.

GRABER: In plants, breeders and researchers like Joyce so far haven’t seen any major bad side effects from CRISPR. They are keeping an eye out, of course. And, of course, regulators are going to be asking questions about things like this before they approve any new crop for the market, right?

TWILLEY: You say “of course,” but, actually, Jennifer told us that that’s one of the things about CRISPR-edited crops. They’re not regulated like conventional GMOs.

GRABER: And this is where things get even weirder and more complicated. The Department of Agriculture, the USDA, has to approve crops grown in the field. And the way the regulations are written now, a crop is only considered genetically modified if it has foreign DNA in it. But it’s easy to use CRISPR to make a change and then get rid of it, so there’s no bacteria left.

KUZMA: And so therefore we have a couple dozen and probably more, approaching 30 to 40 now, crops that have not been regulated from a pre-market standpoint and didn’t have to undergo field trials by the United States Department of Agriculture.

TWILLEY: This is actually one of the things that scientists and start-ups love about CRISPR. Yes, they love how precise it is. But they also love the price tag. Because putting a GMO crop through field trials—that’s really, really expensive.

KUZMA: Some have estimated hundreds of millions of dollars to get a crop, a genetically engineered crop through the regulatory system. Now I don’t think it’s that high. But it is costly. At least a million, probably.

GRABER: Yes, CRISPR scientists love that regulatory loophole. But as it turns out, CRISPR can be used to insert a foreign gene, too, and it can do so a lot more precisely than genetic engineering systems did in the past. That’s something Yiping has been working on, but it’s not easy.

TWILLEY: In other words, Yiping thinks you could one day use CRISPR to put a fish gene in a tomato, and you could do it with great precision.

GRABER: But then it would be regulated the way the original fish tomato was, and, like we said, that cost a lot of money.

TWILLEY: But, for now, like Jennifer says, the USDA is not bothering itself with CRISPRed crops. Because they don’t have new DNA. But there’s a different agency in charge of approving whether that crop makes it to market as a human food. The Food and Drug Administration.

KUZMA: Now FDA does have a policy and it’s a voluntary policy—the Food and Drug Administration—to review these cops for food safety concerns.

GRABER: That voluntary policy just compares the CRISPRed food and makes sure that it’s substantially the same as the non-edited food. But again, voluntary.

TWILLEY: Jennifer says most companies seem to be going along with this voluntary check. And, in fact, to give credit where credit is due, it was the FDA that caught the problems with extra bacterial DNA in those hornless cows. The company wanted to send them out to the slaughter house to turn into hamburgers, and so the FDA took a look. They literally examined the genetic code of these new hornless cows, and they spotted the extra bits of DNA that weren’t supposed to be there, and they said, “Excuse me, we seem to have a problem here.”

GRABER: This is exactly what the FDA is looking for—these off-target effects, unexpected side-effects that might have come along with the intentional gene editing.

KUZMA: And so they do check for things like, is what you’re modifying going to cause more allergens in the food, or is it going to decrease the nutritional value of the food, or increase the toxicants in plants. Plants have a lot of toxic chemicals to ward off pests. And so whenever you make a genetic modification it can increase or decrease those toxins and the nutrients as well.

TWILLEY: So having the FDA check all that sounds like a good idea. But, Jennifer told us that what’s not happening is any ecological field testing for environmental effects—so like effects on pollinators or other plants. That kind of testing would be done by the USDA, and, like we said, they don’t screen these new crops unless they contain foreign DNA.

GRABER: This loophole seems like it could potentially be an issue—but, in a way, Jennifer says the loophole has been good for the field, because there’s been a lot more creativity. More scientists have been able to use CRISPR to see how it could help improve all sorts of crops, and not just the big money-making ones. They’re using it on orphans like ground cherries.

TWILLEY: And regionally important crops like cassava and millet that millions of people depend on in developing countries but that have never had the kind of investment that gets lavished on commodity crops like corn and wheat.

KUZMA: And you can do things that are better for the environment or better for health without having to really recoup your investment in the technology. So some people say it has a democratizing force on the technology, so that a wider variety of actors not only big industry are able to play in this space of CRISPR technology

GRABER: And because CRISPR is so fast, so inexpensive, and can target multiple regions of the genome, scientists are using it to try to make changes in response to the challenges that farmers are facing now, as the climate’s changing. They’re trying to do things like make plants more drought resistant, or capable of tolerating hotter temperatures.

QI: So I think CRISPR can sort of help us catch up climate change.

TWILLEY: This is not a super inspiring reason to love CRISPR—basically, everything is going to hell so fast the plants can’t keep up so we have to use CRISPR to help them evolve faster—but hey, that’s the boat we’re in these days.

GRABER: Another sucky thing that CRISPR might help with—nearly all the bananas that are grown commercially in the world are all the exact same variety, and they’re threatened by a banana fungus. Scientists are using CRISPR to try to help make our bananas resistant to that fungus. Again, crappy reason—can’t we just start eating different types of bananas? But CRISPR does seem to offer one potential solution, if it works.

TWILLEY: Maybe more excitingly, CRISPR can also help us move away from those kind of monocultures and that reliance on just a dozen major crops. That’s part of why Joyce is CRISPRing the ground cherry.

VAN ECK: So there’s a big emphasis right now especially on diversifying our diets. Eating more fruits and vegetables, you know. And is ground cherry going to be a huge production like tomato or corn? No, but again it does give us another option for not only fresh fruit but it can be used as dried and put in granola and cereals and jams and juices as well.

GRABER: But. But, but, but. It won’t surprise regular Gastropod listeners to know that CRISPR is not the solution to all our problems.

TWILLEY: We are not going to wake up tomorrow to a supermarket full of new and improved CRISPRized crops. For one, CRISPR works slightly differently in every different plant, and not all plants are super amenable to being CRISPRed. We’ll still need traditional breeding—CRISPR is not going to replace that.

GRABER: Plus, biology is super complicated. We haven’t sequenced the genomes of all the plants. And doing it at the level of detail you’d need for CRISPR takes a long time and is really expensive. And even if we have that, we don’t know what all the genes do. And even when we do think we know that, well, we’re often wrong. Biological systems are not like a computer code, where basically you write something and the computer responds the way you tell it to.

TWILLEY: Meanwhile, while we figure out the biology, we also need to figure out the policy side. There are a lot of things we could get right with CRISPR-edited crops that we got wrong with GMOs. Like clear and transparent labeling.

KUZMA: I think by putting these genetically engineered products on the market back in the mid-90s without people really being aware and without labeling them, I think people felt duped or tricked in a way in that, oh really? I’ve been eating these for 20 years and I don’t know?

GRABER: And so in order to change the conversation around these next-gen gene-edited foods, Jennifer thinks they should be labeled, too.

KUZMA: I mean, the way I view it is if you think this technology—which I used to be a plant bio-engineer—if you think it’s wonderful and it can do great things and you’re sure about its safety, then label it and be proud of it and show people what it can do for them. Show them how you can make tastier products or more nutritious products or healthier products or ones that are better for the environment, that use less pesticides or less fertilizer. Show them that and be proud of it and label it.

TWILLEY: Some of the scientists who work with CRISPR in crops share Jennifer’s opinion. And some are like, well, we don’t need to be labeled or regulated because this is so precise and nothing is a problem, and just leave us alone to work our magic. And to a large extent, they have a point—most CRISPRed crops seem just fine.

GRABER: But Jennifer thinks a little bit of caution and little bit more public discussion is a good thing. The plants seem fine, but they’re new—plus, Jennifer says that caution and discussion and transparency will help us all be more comfortable with using these technologies.

KUZMA: I know I tend to feel better knowing that somebody is looking out for me with consumer products, whether they be food or otherwise.

GRABER: Personally, I’m with Jennifer.

TWILLEY: It’s hard to predict how CRISPR might transform our food. Our yogurt has been CRISPERized for more than a decade and, in some ways, it seems like nothing has changed. But Dennis told us that in fact, CRISPRed bacteria are so reliable and high performing that yogurt companies don’t have to use additives to make sure they get the texture and creaminess they want. The microbes don’t need that back-up anymore, so those kinds of stabilizers and thickeners are being used less often.

GRABER: And so maybe if CRISPR can help Asian farmers produce more rice in their rice paddies, they’ll earn more money, which is great, and also maybe something else could happen—maybe they won’t have to convert more land to farmland, which could potentially be better for the environment. Dennis had no idea what was going to happen when they discovered how CRISPR worked in bacteria, and we don’t know where CRISPR is going to take us next.

TWILLEY: Cynthia, you asked at the beginning of the show whether we should be worried or excited about CRISPR in our food. And the answer is yes. Worried and excited.

GRABER: How about cautious and excited? That’s how I’m feeling.

TWILLEY: OK cautious, excited, and kind of amazed that I finally understand what all the hype is about.


GRABER: Thanks this episode to Dennis Romero and Annie Millen at DuPont.

TWILLEY: And to their former colleague Rodolphe Barrangou for originally telling me the CRISPR yogurt story back in 2014.

GRABER: Thanks also to Joyce Van Eck at the Boyce Thompson Institute, to Jennifer Kuzma at NC State, and to Yiping Qi at the University of Maryland—we have links to them and their work at gastropod.com. And I highly recommend you try a ground cherry if you’ve never had the pleasure.

TWILLEY: Finally, thanks to our fabulous former intern, Emily Pontecorvo, for finding some of the news footage we played during this episode. We miss you, Emily!

GRABER: We’ll be back in two weeks with something we’ve definitely earned this episode—a drink! But not just any drink. All I’ll say is three dots and a dash. Can you break the code?


TRANSCRIPT Omega 1-2-3

This is a transcript of the Gastropod episode, Omega 1-2-3, first released on August 13. It is provided as a courtesy and may contain errors.

PAUL GREENBERG: It was a little bit of a grueling thing. It’s funny. I was—I never went out on a Jet Ski as a younger person, and I was, I think, 47 when I started on this on this book. So you know it turns out riding a Jet Ski is not a lot of fun, if you’re 47.

NICOLA TWILLEY: The Jet Ski mounted hero of today’s episode is… 47-year-old Paul Greenberg.

CYNTHIA GRABER: Well, he’s not 47 anymore. That was when he started the book, so he’s a few years past that now.

TWILLEY: Like us all, he’s getting older. And that, actually, is what led him to the topic of his book.

GREENBERG: I did start this book in, you know, in the throes of kind of a panic about middle age. And when you Google all the things that are going wrong with you in middle age—your joints hurt, your blood pressure is going up, losing your memory—and you Google solutions for this, you know, what comes up again and again are Omega-3 supplements. So it struck me as a way, a lens for looking at the Omega-3 was to look at it through the lens of the sort of panic that you that you get in middle age around all these things.

TWILLEY: This episode is not about the panic.

GRABER: It’s about the Omega-3s. In fact Paul’s book is called The Omega Principle. Omega-3s have come up in our reporting this year, you might remember we talked about how important these fats are in our Alzheimer’s episode. But what are Omega-3s?

TWILLEY: And why is everyone from Dr. Oz to the American Heart Association telling us to eat more of them? Is there any science behind the idea that Omega-3s are miracle molecules?

GRABER: You’ve probably heard that there are Omega-3s in oily fish like salmon, but what about the pills you can buy at the drug store? Where does the Omega-3s in those come from?

TWILLEY: And what is this Omega-3 boom doing to our oceans, not just our bodies?

GRABER: All that, plus some adorable and mischievous sea lions. But first, we have some really exciting news: we are turning five! Next month!

TWILLEY: I know, we don’t look it. Or even act it sometimes. But it’s true. And five in podcast years is like… I don’t even know. It’s impressive. And we want to celebrate!

GRABER: But we need your help to do it! We’re planning a special birthday episode for September—yes, there will be birthday cake, at least the story of birthday cake—but the episode will be built on your votes.

TWILLEY: That’s right, we need your help to plan the perfect birthday party episode. We want you to vote for your favorite episodes from our first five years, so we can revisit the top ten in our birthday show! We have a link to our voting form on our website.

GRABER: We can’t make this special episode without you, so go vote! You have until August 23 to vote!

TWILLEY: Okay, we’re about to get back to this episode—which was made possible thanks to generous support from the Alfred P. Sloan Foundation for the Public Understanding of Science, Technology, and Economics, as well as the Burroughs Wellcome Fund for our coverage of biomedical research.


TWILLEY: So 47-year-old Paul is on a Jet Ski with his guide, Jet Ski Brian.

GREENBERG: And so I told him I didn’t really want to go fishing. I wanted to actually watch this company called Omega Protein fish for menhaden.

TWILLEY: Paul was on his Jet Ski, in the Chesapeake Bay, watching this big blue ship scoop up these tiny silvery fish called menhaden. The company that owns the ship— Omega Protein—it’s actually the largest processor of menhaden in the U.S..

GRABER: Paul watched the mother ship lower little aluminum baby ships into the water. The boats circled the school of thousands of menhaden, and they scooped them together with a net.

TWILLEY: The ocean went frothy as the little fish thrashed around in the net, and Paul said suddenly the air smelled like watermelon—apparently that’s what menhaden smell like, although I wouldn’t know because I’ve never eaten one.

GRABER: Me neither, and probably none of you listeners have either. Because none of these oily menhaden get eaten—they’re being converted into things like fish meal and fish oil—fish meal to feed animals. And fish oil for Omega-3 supplements.

TWILLEY: So what are these magical Omega-3 things?

GREENBERG: Omega-3 fatty acids are polyunsaturated fat fatty acids. You know you can go wheels within wheels to get more and more deeply exactly what that means, but basically what it means is that they have a double bond at the tail end of their structure between two carbon atoms. And that makes them much more sort of dynamic and flexible.

GRABER: And that flexibility of these Omega-3 fatty acids is awesome for fish that swim fast in cold waters. But these types of fats first evolved not to help with swimming but to turn sunlight into energy. They played a key role in photosynthesis in the very earliest and simplest microscopic creatures that swam in the oceans.

TWILLEY: These little phytoplankton guys, they’re like tiny, super-basic algae. They only did one thing, which was photosynthesize. And they were making Omega-3s to grease the wheels of their sunlight harvesting machinery. And they got really good at it. They harvested so much sunlight and breathed in so much carbon dioxide that they completely changed Earth’s climate.

GREENBERG: But not the climate change we are all obsessed with. But climate change going in the other direction. So back in the days of the early Earth, we had a atmosphere that was very soaked in carbon dioxide.

GRABER: As you might have heard, carbon dioxide in the atmosphere keeps things pretty hot. So then when those phytoplankton used a lot of carbon dioxide, the atmosphere got colder. Pretty dramatically colder.

TWILLEY: Which fortunately the little phytoplankton could adapt thanks to … our heroes, the Omega-3s.

GREENBERG: It turns out that having Omega-3 fatty acids in your membranes makes your membranes more pliable and more dynamic at colder temperatures.

GRABER: One important thing about Omega-3s is that they come in different flavors. There’s the one used in photosynthesis called ALA, and it’s still around in leafy green plants today. And then there’s one called DHA. The early sea creatures turned their ALA into DHA to make them cold-water powerhouses.

GREENBERG: And that’s basically it was used for. But you know as evolution goes of course whatever things were originally designed for gets repurposed and reconfigured for other purposes further down the line.

TWILLEY: The first phytoplankton were photosynthetic, but if you have a system for gathering light, it’s just a few short evolutionary steps to having a system for sensing light. Aka the eye. And these plankton with eyes became hunters—they started eating the eyeless photosynthetic plankton to get their energy.

GRABER: And then at some point in evolutionary history, those hunter plankton didn’t bother making Omega-3 fatty acids themselves anymore. They just ate them.

TWILLEY: Those Omega-3s—specifically the DHA variety—they still play an essential role in the parts of the eye that pick up light. For all animals with eyes, including us. We couldn’t see without Omega-3s.

GREENBERG: What I found throughout looking at Omega-3s was it’s kind of the Forrest Gump molecule.

GRABER: First of all, Omega-3s are everywhere in the plant world, because they’re critical for photosynthesis. Omega-3s are literally the most abundant fat on earth. And then, as we just said, they’re critical in all animal’s eyes for the same light sensing reason.

TWILLEY: Basically, they’re so bendy and flexible that they’re super useful anywhere you want to be dynamic and mobile—anything that has to move fast or transmit signals fast.

GRABER: Moving fast—so remember those tiny watermelon-scented menhaden? They have to swim super fast in cold water. And so they are super oily and packed with Omega-3s. And another tiny creature that has to swim really fast? Sperm. Also full of oily Omega-3s.

TWILLEY: Other places you might find this Forest Gump molecule are the heart—depending on your blood pressure, that’s moving pretty fast. Also, hummingbirds. Their wings have to beat 52 times per second and so those muscles are crammed with Omega-3s.

GRABER: Another weird place you can find Omega-3s: in the hooves of the caribou that roam the frozen tundra. The fact that Omega-3s stay flexible in the cold helps keep the caribou’s blood circulating even when their hooves are marching through the super cold permafrost of the Arctic.

TWILLEY: But the tissue with the largest amount of Omega-3s is your brain! Your brain isn’t moving, but all the cells in it are sending signals really fast, so they need to be bendy and flexible too.

GRABER: In fact, a few decades ago, a scientist named Michael Crawford got interested in the relationship between Omega-3s and our brains.

GREENBERG: Yes, so Michael Crawford, he was based in Africa and he did some initial look—sort of looking at comparative analysis of different brains. And I think he looked at 40 different mammalian brains and what he found was that the size of your brain was directly dependent on the amount of DHA Omega-3 fatty acid that was available. So that, you know, sort of leading to this conclusion later on that Omega-3s, DHA Omega-3 fatty acids were an essential part of the human brain.

GRABER: As I said before, those earliest hunters with the earliest eyes, they didn’t bother making Omega-3s, even though they needed them, because they could just eat them. And we’re the same way. We eat all the Omega-3s we need, either from green plants or really mostly from oily fish that eat those plankton to power their cold-water-tolerant bendy muscles.

TWILLEY: There are so many freaking phytoplankton making Omega-3s—I mean, literally, there’s one species of phytoplankton alone that is the most abundant species on earth. So although almost all animals need Omega-3s, pretty much none of them actually bother making them.

GRABER: Omega-3s are the fats everyone is obsessed with, and you can see why—we need them to think. And to see. But they aren’t the only Omega fats out there. Any plants that can photosynthesize can make Omegas—and not just Omega-3s.

GREENBERG: So there are Omega-6s, there are Omega-9s. Omega-12s. There’s all sorts of Omegas.

TWILLEY: You’ve probably heard of Omega-6s, they’re not as famous as Omega-3s, they’re like the less well-known, less desirable sibling.

GREENBERG: Organisms that use Omega-6s as their primary fatty acid tend to be more rigid. Because the Omega-6 itself is a much more rigid structure. So when we look at things like corn and soy, particularly corn oil and soy oil, they tend to have a nutritional profile that leans towards Omega-6. And in fact many things on land are going to tend towards Omega-6 because, well, they need to stand upright.

GRABER: Omega-6s are also actually a critical part of our diets. We’d die without them. They’re in seeds and seed oils—corn oil, sunflower and safflower and soy oil, sunflower seeds, pumpkin seeds.

TWILLEY: And even though they’re essential, they get a bad rap these days. Which we’ll come back to.

GRABER: Yes, we are going to come back to the relationship between these fatty acids and our health—but overall, it’s clear that these fatty acids are found in so many parts of our bodies and that they’re essential to our existence. But how did we figure that out?

TWILLEY: The answer involves rats with dandruff, Spam, and a Baptist scientist.

GRABER: This story starts back in the 1800s. That’s when scientists first really started to figure out what it was in food that was good for us.

GREENBERG: So you had the 19th century, which was all about the discovery of vitamins and minerals, right? And we kind of went through that whole thing.

TWILLEY: We talked about that whole thing in our vitamin episode—this complete shift in our understanding of what food was doing for us and our health.

GREENBERG: And into the 20th century, you know, medical research was always looking for new angles and people started to wonder did fat have any kind of nutritional quality to it.

TWILLEY: Back then, everyone knew fat was a great source of energy, in the form of calories. But no one realized fat was essential—like, you’d die without fat.

GRABER: Until George and Mildred Burr came along in the 1920s.

GREENBERG: These two scientists, the Burrs, a husband and wife team that did these deprivation experiments with rats where they deprived them of fat and then saw that when they didn’t have fat they actually wasted away and had all these other physiological problems.

GRABER: The rats looked pretty bad without any fat in their diet. They had dandruff and scaly skin. Their tails swelled and got ridges. They had no fur around their faces. And then they died.

TWILLEY: But if the Burrs gave them just three drops of lard before it was too late, they recovered! Pigs eat everything, some of those things have Omegas in them, and so lard has some Omega-3s and 6s in it. Not that anyone knew an Omega from Adam at the time. Omegas hadn’t yet been discovered. No one knew which of the chemicals in fats was saving the rats’ lives.

GREENBERG: So it was established that fats were important. But then what kinds of fats? And then a lot of sort of deepening research happened in the 50s, 60s, and 70s.

GRABER: Ralph Holman is the guy who discovered the Omegas. George Burr was his thesis advisor.

TWILLEY: George and Mildred Burr did their rat fat deprivation study and then they quit and moved to Hawaii to study pineapples. And Ralph Holman picked up the fat torch.

GREENBERG: He used to work for the Hormel company that was, you know, worked on Spam and so forth.

GRABER: All the different fatty foods and oils you might find in your kitchen have a combination of different fatty acids in them. Like lard, which is mostly an animal fat you’ve heard of called saturated fat, but it also has these Omega unsaturated fats. And some of those different types of fatty acids go rancid more quickly than others. Hormel wanted Ralph Holman to figure out which fats went bad, so the company’s Spam wouldn’t go bad.

TWILLEY: So Ralph did experiments to figure out what all these different fatty acids are. Which meant he was the one who discovered Omegas. And got to name them.

GREENBERG: But he was a Baptist growing up and he knew his Bible really well and he came up with the nomenclature and decided to call it Omega-3. Because there’s a line, I think, in Revelations. I am the Alpha and the Omega, the first and the last, et cetera, et cetera.

TWILLEY: In the Greek alphabet, Alpha is the first letter, and Omega is the last. It’s at the end. And that’s also where the distinguishing feature of these special fats is—the chemical structure that makes them so bendy and pliable.

GREENBERG: So if you count three carbon atoms in from the end, that’s where you’ll find your first double bond. So that’s why it’s called the Omega-3.

TWILLEY: And if the first double bond is six carbon atoms in—well, you’re looking at an Omega-6. And so on. Omega-3s just have more double bonds all along their length.

GRABER: These double bonds are what make them so flexible. But these bonds also react really easily with oxygen, and that makes them turn rancid super quickly. Ralph’s discovery was useful to Hormel—eventually scientists figured out how to get rid of those Omega-3s in processed foods to make them more shelf-stable.

TWILLEY: So at this point in history, thanks to George, Mildred, and Ralph—

GRABER: And Spam

TWILLEY: —all thanks to spam—so at this point, we’ve identified Omega-3s, we know that rats will develop dandruff and die without fat, but we don’t know what those fats are doing that is so essential. Meanwhile, scientists have started connecting animal fat and cholesterol to heart disease.

GREENBERG: And so there were these two doctors named Bang and Dyerberg who went to Greenland in the early 1970s

GRABER: Olaf Bang and Jorn Dyerberg went to Greenland because the Inuit there seemed like a paradox. They ate a lot of meat, mostly from seals, and a lot of fat. At the time, meat and saturated animal fat were thought to be the main cause of heart disease—but the Inuit had really low levels of heart disease. So Bang and Dyerberg tested their blood.

GREENBERG: And they were the ones who discovered that Inuit populations there had very, very high levels of Omega-3 fatty acids in their blood. They also had a diet that consisted primarily of marine mammals and fish.

TWILLEY: While Bang and Dyerberg were doing their Greenland thing, Michael Crawford was doing his brain measuring thing. And suddenly Omega-3s were the hot new molecule on the block.

GREENBERG: It all kind of sort of smushed together. I think the very first dietary supplements that we started to see—Omega-3 dietary supplements—were really kind of like early 80s.

GRABER: These might have been the first supplements with the words ‘Omega-3’ on the label, but they certainly weren’t the first time we used fish oil as medicine. Which we are going to tell you all about.


GREENBERG: Yeah. So garum might just be the world’s first Omega-3 dietary supplement. It was an ancient fish sauce that seems to have come possibly from the Phoenicians, although we don’t know, I wasn’t there.

TWILLEY: The theory is that this fish sauce made its way from the Phoenicians through the Greeks and eventually to the Romans.

GREENBERG: What we do know for sure is that the Romans absolutely loved it. And, in fact, if you go to Pompei, if you were to try and reconstruct what Roman civilization was built around based upon what you found in Pompei, you would conclude that it was primarily a fish-sauce manufacturing country or empire. Because that there were so many vessels of this fish sauce called garum found everywhere.

GRABER: To make garum, ancient Romans took whole anchovies or mackerel, guts, heads and all. They mixed the fish with a lot of salt. And then they let the whole mess rot in the sun for months. They’d stir it occasionally, some people would add some wine. And, at the end, they’d funnel off the resulting liquid.

GREENBERG: Romans used it as a condiment. It was found in ancient recipes. It’s more common than salt in the recipes. So it was very salty so it provided that aspect to it. But it had a certain kind of stinky, umami-ish thing that it gave to food.

TWILLEY: Sounds delicious! But garum was more than just fish sauce. It was a supplement. Romans poured it down the noses of sick animals, they took it as a laxative, but also to cure chronic diarrhea, they believed it could restore a lost appetite, and treat everything from tuberculosis to migraine headaches.

GREENBERG: People used it as a curative as well for sciatica. Some people thought it could cure an upset stomach. People associated with with amorous qualities as well.

GRABER: It was a big deal. Romans brought their garum with them everywhere. Turns out, they might have been on to something.

GREENBERG: Recently some Spanish food scientists recreated, reconstructed how you would have made garum. They did that and then they sort of tested it for its nutritional qualities and it had a number of very useful nutrients including being very high in Omega-3 fatty acids.

GRABER: You might never have heard of garum, that’s kind of ancient history. But you might have heard of something that was used for a lot of the same health benefits, and that’s cod liver oil.

TWILLEY: Or maybe not, because, if you remember taking cod liver oil, you are pretty much an archaeological specimen yourself.

GREENBERG: Cod liver oil is sort of an interesting case because—so those who are a little bit older might remember a day when they didn’t know exactly what Omega-3 was but they did take cod liver oil. Cod liver oil is actually very high in Omega-3s. And the reason—so cod themselves, if you eat a fillet of cod, it’s actually not particularly Omega-3 rich or particularly oily. Cod tend to store their oil in their liver. And one of the reasons they do that is because it allows them to shuttle the Omega-3s over to their gonads when it’s time for reproduction.

TWILLEY: And just like human testicles, cod balls require plenty of Omega-3s to do their sexy thing.

GRABER: So we humans have been taking Omega-3 supplements in fish oil for thousands of years actually, if you consider the history of people swallowing some garum or cod liver oil to help with various ailments. They didn’t know those were Omega-3s. The people buying supplements today, though, they certainly do.

GREENBERG: Ralph Holman went to the store—this guy who had named them the Omega-3 fatty acids—went to a store and saw a jar of supplement—of fish oil—and it said “Omega-3s are here!” And he bought it. And he was so excited!

TWILLEY: Today, Paul says that Omega-3s supplements are a $15 billion industry—an industry that is still growing at seven percent each year. Omega-3s are also one of the world’s most profitable supplements. After all, they’re supposed to help with diseases of aging—heart disease, dementia, cancer, even—and the West is clogged up with all these boomers right now, who don’t want to go quietly into the night.

GRABER: But as a big a market as those aging boomers are for the supplement industry—and it’s a huge, huge market—it’s actually not the biggest market for these tiny fish. Today, oily fish, full of Omega-3s, are a super important ingredient in animal feed.

GREENBERG: And this is really the key, the killer app, so to speak, for little fish. First they started feeding all these little fish to chickens. Then they fed them to pigs.

TWILLEY: What happens is, in industrial hog production, piglets are not allowed to nurse for very long, so they don’t get enough Omega-3 fatty acids from their mothers milk. So the farmers have to add Omega-3s to pig infant formula.

GRABER: And this means that fish oil and fish powder have gone industrial. Chicken feed, pig feed. And actually it’s a major ingredient in cat food, too. And so a lot of the fish caught in the world are not eaten as fish.

GREENBERG: Yeah, a lot. It’s something like 20 to 25 million metric tons a year, which is, you know, around close to a quarter of all the fish that we catch is reduced. This completely invisible thing. And you know if you were to weigh that—you know, 25 million metric tons, what is that? That’s actually the equivalent of the human weight of the United States taken out of the sea every year.

GRABER: It is impossible to picture that, but, obviously, it’s a lot.

TWILLEY: Today, the biggest market for all those ground up tiny fish? Is: Other fish. Farmed fish.

GREENBERG: Because there are a lot of fish out there that just simply need Omega-3s. They just will die if they don’t get Omega-3s—salmon being one of them. So probably the global salmon industry is probably the biggest market right now for all these little fish.

GRABER: It’s not just that some animals can’t live without Omega-3s—salmon, for instance, and baby pigs. It’s also that other farmed fish, they grow faster when their diets are supplemented with fish meal.

TWILLEY: The little fish that are feeding all these bigger fish—for the most part, we’ve never heard of them. Like the menhaden that Paul Jet Skied out to see in the Chesapeake. Or like the Peruvian anchoveta.

GREENBERG: Which is the largest fishery in the world. Sometimes it’s been as much as more than 10 percent of the world catch.

GRABER: Paul traveled to Peru to see what a fish catch at this scale looks like. He sailed with a fisherman out into the turbulent Pacific at 2 AM.

GREENBERG: And I thought we were immediately going to go to the fishing grounds, but instead we stopped about an hour or two in and just waited. And I said why, why are we waiting? He’s like, well, we have to wait for the other boats. I’m like, you know that just goes totally contrary to everything a fisherman always thinks. You know, I want to be the first one out to the grounds.I was like, why? He’s like, well, you’ll see.

GRABER: So they wait. And then suddenly there are dozens and dozens of boats all around, all sailing together towards the same point.

GREENBERG: And I realized why we were doing this and the reason we were doing this is because there were so many sea lions that immediately got on the fishing nets that if you didn’t have a number of boats they would all congregate around one boat and eat basically eat your net to shreds. And what was really interesting about it was that you know you always see these sort of Greenpeace moments of like, oh, the poor sea lion who got caught accidentally. He was just minding his own business and he got scooped up by the net. But what was kind of crazy about this Peruvian situation—the sea lions totally knew the game.

TWILLEY: These sea lions were just lounging around, waiting for the humans to gather all the anchoveta together into a nice oily anchoveta ball. And then they would jump in the net.

GREENBERG: And they would just you know sit there and they would just eat and eat and eat and eat. And people would be shouting at them and they’d be like, they’d stick up their noses. Oh no, it’s too delicious here. I don’t want to leave! And eventually they would kind of harass them enough so they would leap over the net and get out.

GRABER: So it looks to Paul like a pretty healthy ecosystem. There are clearly a lot of fish out there, and the fishermen are all pulling in quite a hefty haul.

TWILLEY: In both Peru and in the Chesapeake—there seem to be shedloads of tiny fish, even though these companies scoop out so much.

GREENBERG: Everybody will say that their industry is totally sustainable, that they’ve—you know, they used to be overfished but now they’ve really worked it out and da da da. And granted a lot of these countries and regions and companies have made adjustments. But I always go back to the fact of what if 25 million metric tons of fish were still in the sea? What would the ocean look like if we had 25 million extra tons of prey, of food for whales, for birds, for the fish that we like to eat. And nobody could ever give me a clear answer on that.

TWILLEY: Paul’s point is, these little oily fish, they would normally be eaten by other sea creatures, or by seabirds, or they’d die and their nutrients would cycle around in the marine ecosystem. But now that food source is gone.

GRABER: And, frankly, any time we humans think there’s an endless supply of something, well, there isn’t. Hundreds of years ago, sailors said there was so much cod in the Atlantic they could practically walk across it. Then we fished nearly all of it.

TWILLEY: We talked about this in our counting fish episode—there are plenty of fishermen today who will still say there’s loads of cod in the ocean, even though there’s nowhere near as much as there used to be. It’s called a shifting baseline.

GREENBERG: And shifting baseline basically says that each successive generation has a diminished view of what it perceives as abundant in nature. Like the example of codfish: if I go out nowadays out of Long Island and I catch five codfish, I’ll think that I would have had a fantastic day. My father, if he goes out, if he catches five codfish, will think it’s a miserable day. And my grandfather, if he’d gone out, would think like what the heck has gone wrong in the universe that you could only catch five codfish.

TWILLEY: In other words, we don’t really know the environmental impact of our hunger for Omega-3s. But it’s a safe bet that there is one, and it isn’t great.

GRABER: But doctors and scientist are telling us to eat seafood, salmon in particular, and a lot of them are also suggesting Omega-3 fish oil pills. And both of those things are exactly what the Peruvian anchovetas are getting turned into. So maybe it’s worth it?

TWILLEY: Only if Omega-3s are doing all the miraculous things people claim they’re doing. Which, it turns out, scientists do have something to say about.


JOANN MANSON: The interest in Omega-3s has waxed and waned over the decades.

TWILLEY: This is JoAnn Manson—she’s an epidemiologist at Harvard Medical School.

MANSON: Interestingly, about 30-40 years ago, there was tremendous interest in Omega-3s in having a role reducing cardiovascular disease.

GRABER: This is the time that people were concerned about animal fats and heart health, and Bang and Dyerberg saw that the Inuit were doing well with their Omega-3 rich diet of seals and fish, so maybe Omega-3 pills would help the rest of us.

MANSON: And some of the randomized trials of Omega-3s that were done in the 1980s, 1990s looked promising. But then more recent trials were actually disappointing.

GRABER: There was a big study last year that looked at other studies—it’s called a meta analysis. And it showed that there was actually no heart benefit from taking Omega-3 fatty acid supplements.

MANSON: And that led to a lot of discouragement about Omega-3s.

TWILLEY: But JoAnn says the problem was that there were problems with a lot of these earlier studies.

MANSON: So the randomized trials of Omega-3s have included some trials with lower doses that may not be adequate dosing. Some trials that were short duration, even less than a year, or only one to two years. It’s been a mixed bag.

GRABER: Those earlier studies were also done on patients who already had heart disease, or had suffered from a stroke, or they had diabetes—they basically already had health issues. Which meant they weren’t necessarily a great test of whether Omega-3 supplements would help the general public.

TWILLEY: So JoAnn set up a trial of her own.

MANSON: Well, very surprisingly, the Vitamin D and Omega-3 trial, VITAL, was the first large scale randomized clinical trial of Omega-3s in a true usual risk population.

GRABER: JoAnn’s trial was called VITAL, and it was a fully randomized, double blinded trial. That meant some of the participants took a supplement, and some took a placebo, and none of the doctors knew which was which.

TWILLEY: There were more than 25,000 participants, all over fifty years old.

MANSON: But they were just all comers. Some of them did have hypertension or diabetes as you would have in the usual population but they were generally healthy.

TWILLEY: The folks in the trial who were getting the fish oil supplement got a gram of Omega-3s a day, the others took their placebo, and then JoAnn sat back and waited—for more than five years—to see what happened to everyone.

GRABER: JoAnn told us that if you look at how many people in the trial ended up having a heart attack or a stroke, well, the Omega-3s didn’t make a difference. But that changed if you took strokes out of the equation.

MANSON: We saw a reduction in fatal heart attack, about a 50% reduction there. So we did see significant reductions in coronary heart disease related events. We saw no reduction in stroke.

GRABER: Okay, no reduction in strokes, but the reduction in fatal heart attacks is intriguing.

TWILLEY: Where it gets really intriguing is in the differences between different participants. People who ate less than one and half servings of fish a week—so they weren’t getting a lot of Omega-3s in their normal diet—those people, if they got the Omega-3 supplement, a statistically significant percentage of them had a reduction in heart disease overall, even including stroke.

GRABER: In comparison, people who did eat fish did not see a reduction in heart disease from taking the supplement. But here’s an important thing to know: the percentage difference might look dramatic, but the numbers are really, really small. For instance, of the more than 13,000 people who didn’t eat a lot of fish, the difference in who ended up with heart disease and who didn’t was only about 40 people.

TWILLEY: Obviously if you’re one of those 40 people who didn’t get heart disease, that’s great, but 40 people out of 13,000 is not nearly the huge impact it might sound like if you just hear the percentage reduction. But it is statistically significant evidence for the benefit of Omega-3s.

GRABER: And there was another subgroup that seemed to benefit more than others from the supplement.

MANSON: We had very dramatic reductions in the risk of heart attack among the African-Americans with the Omega-3s. They actually had a 77 percent reduction in the risk of having a first heart attack. Now this could be a chance finding. This needs to be replicated. Because if African-Americans are benefiting this much from Omega-3 supplementation, it’s really important to know that. And it could play a role in reducing health disparities.

GRABER: Once again, the actual numbers are super super small, so the results are promising, but, as JoAnn says, it could be chance. Plus, we also want to point out that even if there is a benefit from the supplements for African-Americans, it might have nothing at all to do with skin color.

TWILLEY: In general, African-Americans have lower incomes than white Americans, they have poorer access to health care, they tend to live in more polluted areas, and of course, not unrelated to all of those other factors, they’re subject to discrimination and racism.

MANSON: So our findings in African-Americans could be due to a number of factors. One possible explanation is increased stress and even increased exposure to air pollution and some environmental risk factors where the Omega-3s have been implicated in having benefits.

TWILLEY: Right now, the only results JoAnn has from her VITAL trial are to do with heart health. But taking Omega-3s is supposed to have lots of other wonderful benefits, and the trial is looking at them too

MANSON: We’re looking at cognitive function, mood depression, risk of Type 2 diabetes, autoimmune conditions, and a number of other health outcomes. We’re still in the process of doing the data analysis. But stay tuned. We will have results from many of these other studies within the next three to six months.

GRABER: There’s plenty more research ahead, both for JoAnn and for other scientists who are looking at Omega-3s and health. These findings have to be confirmed by other scientists. And there are a lot of questions: how much Omega-3 do we need? Is more better?

TWILLEY: But JoAnn’s study, which is just one study but is a really solid study, makes it seem as though Omega-3 supplements are beneficial for some folks. But assuming other scientists replicate these findings—does that mean people who would benefit from more Omega-3 should get those Omega-3s in pill form?

GRABER: In JoAnn’s study, she had to deliver those Omega-3s in capsules. Otherwise it’d be pretty obvious who was getting the Omega-3 and who had a placebo—some people would be eating a lot of mackerel and salmon and sardines, and some, well, they wouldn’t.

TWILLEY: But outside the constraints of a scientific study, is consuming your Omega-3s as a pill really the way to go?

MANSON: So, I’m glad you asked this question because I think the primary recommendation is to try to increase consumption of fish and not to jump to popping a pill.

GRABER: JoAnn says it’s not clear whether there’s really a difference between the two, but she says that one of the benefits of eating your Omega-3s in fish and not in a pill is that eating fish might be taking the place of eating something that’s not quite as good for you.

MANSON: So if you’re having fish more frequently you may end up having red meat, saturated fat, processed foods less frequently and you’re replacing them with a food that’s more healthful.

GREENBERG: The other issue is that the human body has evolved to incorporate nutrients based on food. And a lipid taken out of context of other lipids, and just sort of just a shot of lipid right there in the morning when people are most likely to probably take their supplement, seems to me maybe out of sync with what the body is able to deal with.

TWILLEY: What’s more, as regular Gastropod listeners know, all supplements are not created equal. Because there’s no real federal oversight of the supplement business, some are pure Omega-3 goodness. And some are not.

GREENBERG: The companies that are making supplements are making them from fish that weren’t necessarily refrigerated upon capture. Omega-3s are very dynamic compounds and they will oxidize very quickly and if they oxidize then they’re not really going to provide the health benefit that we’re looking for.

GRABER: The oils turn rancid, and when they’re rancid, they’re just not good for you any more.

MANSON: So it’s important to look on the label for some of the signs of quality control. The seals of U.S. Pharmacopeia, USP, and NSF. Various ways that you can tell that there’s some external audit going on for quality control.

TWILLEY: OK, but if you do find a good quality supplement— should you be taking it? Should we all be popping Omega-3s, just as back up?

MANSON: So our advice at this point would be not for the entire population to start taking a Omega-3 fish oil supplement because we really are not seeing overall widespread benefits.

TWILLEY: So fish is best. But do I have to eat those watermelon-smelling menhaden or what?

GRABER: Well, not necessarily menhaden—but yeah, different fish have different amounts of Omega-3s. As we said earlier, fish that swim really quickly in cold water have a lot of Omega-3s. You’ve heard of these fatty fish: herring and anchovies and sardines and mackerel and salmon and sablefish, otherwise known as Pacific black cod. Not the cod most people eat from the Atlantic.

TWILLEY: The problem with normal cod and other white fish—haddock, tilapia, flounder, grouper—is that they just don’t get enough exercise. Cod don’t swim for miles and miles and miles, like mackerel do.

GREENBERG: It’ll have a quick lunge but then most of the time it’s kind of a lazy kind of fish. So it’s not so essential to have these hard swimming oils in their bodies.

GRABER: If you’re only eating cod and haddock, you are probably not getting enough Omega-3s in your diet.

TWILLEY: But this question of enough—this is where it gets complicated.

GREENBERG: You know if you’re just talking to your family physician, a lot of physicians will say something like you know 500 milligrams a day. And you can kind of hit that amount if you have, I think it was like something like four anchovies a day. So like you know 8 little fillets of anchovies, which is really not a lot.

GRABER: But if your family physician does say this, well, it’s not actually based on settled science. We don’t know how much we need of these Omega-3s. And there’s another thing that makes this question even more complicated—

TWILLEY: So here’s the thing. We told you we outsource production of Omegas—we just eat them. And we also told you that the Omega-3s used in photosynthesis, the ALAs—that they are the most abundant fat in the world. And then we told you that our brains and our hearts need the other kind of Omega-3s, the marine kind.

GRABER: There’s some good news here—we can actually make that marine kind, in our bodies, from ALA from plants! We can convert the plant Omega-3 from flax seeds and chia seeds and leafy greens—we can convert it into the marine Omega-3 that our brains and our hearts need.

TWILLEY: But can we make enough? No one is sure. And part of the reason no one is sure is because it’s possible that the specific amount matters less than the ratio.

GRABER: Yes, the ratio. Specifically the ratio of Omega-6 to Omega-3. Remember, Omega-6s are in corn and soy, basically in seed oils. Omega-6s are critical, but some scientists think we shouldn’t have too much of them.

GREENBERG: Omega-6s interfere with the body’s ability to elongate short chain Omega-3 fatty acids that we’re getting from leafy greens and so forth. And they also seem to lead to the production of inflammatory compounds.

TWILLEY: And here’s why. Your body uses whichever Omega happens to be handy in order to build all the things it needs to be bendy and flexible, like cell membranes. Omega-3s are the bendiest and most supple of all, but, if Omega-6s are what’s most available, that’s what your body will use.

GRABER: Scientists think that if your cell membranes are made of Omega-6s rather than 3s, they’re not as flexible, and the communication between cells doesn’t work as well.

TWILLEY: And the movement of other chemicals around your body— it’s less fluid and more explosive because the cell membranes are a little stiffer. And some scientists think that more explosive movement is more stressful for your body and can cause inflammation. Which is bad.

GRABER: Right. And, one final point here, food technologists have gotten rid of as much Omega-3 as possible in processed food because it turns rancid quickly, as we told you. Omega-6 doesn’t go bad quite as fast. And corn and soy are so cheap. So our processed food world is full of Omega-6s, far, far more than we would have eaten in the past.

TWILLEY: So are our industrially produced animal products, because cows and pigs and chickens are fed corn and soy rather than grass and bugs and stuff.

GREENBERG: Terrestrial meats that are fed a feedlot diet will have an Omega-6 ratio far in excess of what we think probably Neolithic humans might have had in their own blood.

GRABER: This is all a hypothesis. Nobody has proven this ratio question—in fact, when we asked JoAnn about it, she didn’t even want to touch it.

TWILLEY: The basic mechanisms makes sense, biologically. The idea that the ratio of Omega-6 to Omega-3 in our diet has changed over time, and so has the incidence of all kinds of heart disease and other industrial world health problems—that’s based on observational evidence. But overall, it’s still an argument, not a fact. JoAnn agrees—there’s still huge gaps in our understanding when it comes to Omegas and health.

GRABER: But at the end of the day, whether or not the ratio matters, it’s not a bad idea to add more oily fish to your diet. Fish like mackerel, sardines, herring, salmon.

TWILLEY: Farmed salmon is actually often a little higher in Omega-3s than its wild counterpart. But it’s being fed anchoveta. And Paul says that’s not a good use of anchoveta.

GREENBERG: And you know the people who argue for the Peruvian anchoveta industry doing what it’s doing say, well, I mean, there’s nothing wrong with it. We’re still making human food. We’re just making these pellets that we’re sending to Norway so they can feed salmon. We’re just transforming it. I don’t know if I buy that argument. I think that, you know, a lot is lost in the process and we could probably do a lot better.

TWILLEY: What’s lost is that pound for pound, you are getting less food at the end by feeding the small fish to the big fish, than if you just ate the small fish. So it’s a waste. Not to mention the energy you use to reduce the small fish into pellets and ship them around the world.

GRABER: So it’s not really a great idea to feed the anchoveta to salmon instead of just eating those anchoveta directly—which Paul says taste exactly like anchovies.

TWILLEY: Or just leaving more in the oceans for all the other sea creatures.

GRABER: But Paul says maybe there is a better way to feed salmon and to make supplement oil—

TWILLEY: A way that is in fact how Omega-3s are created in the first place. By tiny microscopic phytoplankton, basically algae. I mean, why not cut out the middlemen?

GREENBERG: Why kill hundreds of millions of billions of fish every year to reduce into the supplement, when you could grow them using algae which would actually sequester carbon and do all these other kinds of things in the process.

GRABER: This is actually something that people are working on—they’re growing algae and harvesting Omega-3s. You can find algae-based Omega-3 fatty acids in supplements at the stores. But they’re really expensive right now. So they’re not being used as salmon feed.

TWILLEY: But hopefully that’ll change in the future. If farmed fish were being fed algae-based Omega-3—well, Paul says, that would be a game changer for the planet.

GREENBERG: So you know I think there are a lot of people out there who like never want to eat a farmed fish. And they think that they’ve heard all these bad things about about aquaculture. But what I realized was that we could conceivably produce fish and shellfish at a fraction of what—using the fraction amount of carbon and a fraction of the energy and just generally have this source of protein that was much greener.

GRABER: This is a change for a fish guy like Paul. He’s spent most of his life and career as a writer focusing on wild fish, but as he wrote this book, he came around to a new idea. Maybe it’s a better idea is to grow algae on land and use those algal Omega-3s to feed farmed fish. And leave more wild fish in the ocean.

TWILLEY: Maybe by growing marine Omega-3s on land, we can have our fish—farmed fish—and healthier oceans too.

GREENBERG: Interestingly, I started this book with this idea of trying to understand what the miracle supplement was. But I came away from it being like, huh, the sea and the products that we could get from the sea could completely reshape the way that we eat and make our footprint on the planet much much gentler.


TWILLEY: But in the meantime, truly, my hot tip is to dissolve anchovies into all your sauces. It’s just salty umami deliciousness, no excess fishiness. Paul actually has even more recipes to help you love oily fish in his book, The Omega Principle, which we have a link to on our website.

GRABER: Thanks to Paul Greenberg this episode, and also to JoAnn Manson of Harvard University. And to the Sloan Foundation and the Burrows Wellcome Fund for supporting our science and health reporting.

TWILLEY: Do not forget to vote for your favorite episode for our birthday special. I cannot wait! I live for birthday cake.

Guts and Glory

What does it mean when your stomach rumbles? How do our bodies extract nutrients and vitamins from food? Does what you eat affect your mood? Digestion is an invisible, effortless, unconscious process—and one that, until recently, we knew almost nothing about. On this episode of Gastropod, we follow our food on its journey to becoming fuel, from the filtered blood that helps slide food into the stomach, to the velvet walls and rippling choreography of the small intestine, to the microbial magic of the colon and out the other end. And we do it by visiting the world's most sophisticated artificial gut at dinner time—a plumbing marvel named TIM that chews, swallows, squeezes, farts, and poops just like the real thing.


TRANSCRIPT: How the Carrot Became Orange, and Other Stories

This is a transcript of the Gastropod episode How the Carrot Became Orange, and Other Stories, first released on November 6, 2018. It is provided as a courtesy and may contain errors.

COMMERCIAL: Carrots! Extreme, impossible stunt! Carrots!

CYNTHIA GRABER: I’ve eaten a lot of carrots in my day and they’ve never sounded quite as exciting or as explosive as they do in this commercial.

NICOLA TWILLEY: I’ve never really seen them as more than a vehicle for hummus, to be honest. But maybe I need to rethink. Turns out, the carrot is pretty wild.

GRABER: Literally. This is Gastropod, the podcast that looks at food through the lens of science and history. I’m Cynthia Graber.

TWILLEY: And I’m Nicola Twilley. And this episode is all about our humble, orange friend, the carrot.

GRABER: First of all, it turns out that the carrot wasn’t always orange. How did it get to be this way?

TWILLEY: And what about all the fancy purple and yellow and white carrots you can buy at the market today—where did they come from, and are they any better than the ordinary orange ones?

GRABER: What about baby carrots, what are those? Are they just stunted tiny little carrots that never reached their full potential?

TWILLEY: Yes, the carrot has its mysteries. And this episode, we travel to Wisconsin—which is a state that grows a lot of carrots—to get to the bottom of them all.

GRABER: And speaking of Wisconsin, thanks again to Laura Heisler for inviting us to headline the Wisconsin Science Festival in Madison last month. It was great fun and a full house—we loved meeting all of you who came out to see us. And don’t forget you can catch us in Philly on November 16—all the info is at gastropod.com.


IRWIN GOLDMAN: This one looks a little more succulent—you want to try to like—should we cut that off?

GRABER: Yeah, let’s try to cut it off.

GOLDMAN: Let’s see if we can get some carrot flavor.

TWILLEY: You can smell it, though.

GRABER: Smells like earth to me. Oh yeah, no, I smell it. It has that kind of parsnip-y, carroty.

TWILLEY: Oh my god. Yeah.

TWILLEY: Picture Cynthia and me standing in a darkened shed on the campus of the University of Wisconsin in Madison. We’re with Irwin Goldman, who is a professor of carrots.

GRABER: And a carrot breeder. He’s officially a horticulturalist. And he’s one of the world’s experts on carrots. Irwin has been working on carrots for almost three decades.

TWILLEY: Like all of our food plants, the carrots we know and love today are quite different from their wild ancestors. And Irwin brought us to his carrot shed to give us a taste of what carrots used to be like, before humans started messing with them.

GOLDMAN: You know, I think a lot of people will be familiar with Queen Anne’s lace as a weed growing along the roadsides here in the Midwest, but actually it’s a ubiquitous weed. It grows everywhere in the world. It has a quite a beautiful cluster of flowers.

GRABER: Until I met Irwin, I didn’t know that Queen Anne’s lace is actually a wild carrot. It’s what carrots were like before they were carrots.

GRABER: Blech, yuck!

TWILLEY: It’s pretty bitter.

GOLDMAN: Yeah it is.

TWILLEY: Pretty bitter.

GRABER: It’s just kind of gross tasting and it’s really fibrous and you can’t really get your teeth around it.

TWILLEY: I feel like I’m gnawing on a piece of wood…

GOLDMAN: Right, exactly.

TWILLEY: …that doesn’t taste very good.

TWILLEY: So yeah, no thumbs up for Queen Anne’s Lace. Irwin had to hack away at the fibrous white roots to get a chunk we could each try. And, really, the flavor was not worth the effort.

GRABER: I couldn’t imagine eating anything like this, but maybe if those roots were boiled forever, which is probably how they would have originally been eaten? I have no idea.

TWILLEY: These wild carrots can be found everywhere now, but the carrot’s original home?

GOLDMAN: Well, we think they come from the mountains of Afghanistan and Central Asia.

GRABER: Irwin says that’s where the wild carrot originates, and it spread long before the domesticated carrot did.

TWILLEY: Philipp Simon is a USDA geneticist and a horticulturalist. His office is down the hall from Irwin at the University of Wisconsin. And he told us that even before people ate carrot roots, they thought the seeds and leaves were useful.

PHILIPP SIMON: Carrots were apparently consumed as a—probably—source of flavoring or more likely medicinal properties three to five thousand years ago, based on the evidence that there is carrot seed near camp sites of humans that long ago in Switzerland and Germany.

TWILLEY: Cultivating carrots for their root—which is the part we use almost exclusively today—that came much later.

GOLDMAN: I think the earliest domesticates, we believe, were purple-rooted and those made their way from Central Asia and made their way into countries like Turkey, where they were really a popular vegetable.

GRABER: It’s not totally clear exactly when this happened, but at some point people in what’s now Afghanistan found carrots that had a purple root instead of a white root.

TWILLEY: But how does a root go from white to purple?

GRABER: Irwin says we need to look at the Queen Anne’s lace flower for the clue.

GOLDMAN: Often it will have a little purple spot in the middle. And of course the legend is that Queen Anne pricked her finger making lace.

TWILLEY: That’s the fairytale, but in scientific terms, what that means is that the carrot plant already had the mechanism to make purple, for its flowers. And then somehow, through a genetic mutation, it started making purple pigments in its roots, too. And people liked these new purple roots.

GRABER: Phil said that women were typically the ones in charge of growing these kinds of crops and choosing ones that were a little sweeter, a little less fibrous, and so they were probably the ones who liked those first early purple carrots and chose them to plant, again and again.

TWILLEY: The purple coloring would have been handy—it meant our ancestors could easily tell the difference between these slightly less fibrous, slightly less bitter purple carrots and the white, wild, woody carrots that grew nearby.

GRABER: And over time, carrots kept on mutating and becoming even more colorful—probably around the same time as purple carrots, carrots also turned yellow.

TWILLEY: I should say, this is all pretty much speculative. Because we don’t really know a lot about the domesticated carrot’s earliest incarnations. Phil says that the earliest good documentation of a purple carrot comes about eleven hundred years ago, in Central Asia.

SIMON: But then as you move west especially through the Middle East and Turkey and then into North Africa, there are written records about purple and yellow carrots. And purple and yellow show up in that written record throughout the period up until about the early 1500s.

GRABER: Purple and yellow sound beautiful, yes, but those aren’t the carrots I grew up with. How did they become orange?

GOLDMAN: That’s the big question in the carrot world. LAUGHS. You know there’s two hypotheses

TWILLEY: If you have ever heard the story of how the carrot became orange, you will likely have heard hypothesis number one: it’s the Dutch. The story goes like this.

GOLDMAN: The prominent hypothesis comes from a scientist named Banga, who is a Dutch scientist who spent some wonderful time touring the great museums of Europe looking at market scenes. And he noticed that there were purple carrots and purple-yellow carrots in the marketplace or in still life paintings. and that those gradually became orange at a certain point in time around the 16th century, mid-16th century, depending on which painting you look at.

GRABER: So Banga came up with this theory in the 1950s: he believed that orange is a relatively recent carrot mutation. Orange carrots appeared in northern Europe, maybe even in Holland, and it was the Dutch that chose to breed and popularize those orange carrots in the fifteen and sixteen hundreds.

GOLDMAN: The Dutch are somewhat famous for their love of orange and the House of Orange and all, and so, you know, I think there’s something really nice about his hypothesis that seems to work.

TWILLEY: For those of you not steeped in Dutch history, the Dutch love of orange can be traced back to William of Orange. Orange is a town in the south of France. William, who came from Orange, led the Dutch in a revolt against the Spanish in the 1500s, which led to The Netherlands finally becoming an independent country.

GRABER: I admit I am mostly familiar with the Dutch love of orange from their World Cup jerseys. But it’s clear, they love it. And the Dutch traditionally grew a lot of carrots. So this story seems nice and pat, the Dutch found an orange mutation of the carrot, and they just bred that mutation like mad. But maybe this story is a little too pat?

TWILLEY: Phil Simon brings us theory number 2 on when and where the carrot turned orange.

SIMON: the earliest orange carrots that show up in artwork are out of Spain and Italy and then very soon after in Germany. And so carrots move from the Middle East to North Africa and then over into southern Europe. And so as they got into southern Europe around late 1400s, early 1500s—that’s when orange carrots first show up in artwork.

GRABER: Irwin agrees with Phil—he thinks that probably that first orange mutation occurred before it showed up in Dutch artwork. He does think that even if the Dutch didn’t discover the mutation, they probably did fall in love with that orange carrot and focused their growing efforts on it. So maybe they are the ones who led to the eventual orange takeover?

TWILLEY: As we speak, Irwin is working on using genetics to get to the bottom of this mystery, although he says that conclusively establishing the date and place when this orange mutation occurred is going to be hard.

GRABER: In any case, the orange carrot won. At least by the 1980s, when Phil started working on carrots, it was—

SIMON: Orange and orange and orange.

TWILLEY: But today when I go to the store, or to the farmer’s market, I can and I do buy purple carrots and yellow carrots and orange carrots and white carrots. All the colors.

GRABER: But these other colors didn’t just re-appear out of thin air, or come out from hiding. They’re basically the original carrots, but they had pretty much disappeared from the marketplace in the U.S. and Europe for centuries. There has to be some story here. Why’d they come back?

TWILLEY: Kind of by accident, it turns out.

SIMON: We were looking at the genetics of color, and, as we were doing this work on genetics of color, we crossed some purple carrots from eastern Turkey with some orange carrots in my breeding program.

GRABER: Phil and his colleagues were interested in whether these colored carrots might have useful qualities that he could breed into orange carrots. Maybe the purple carrot could help Phil breed sturdier, more disease-resistant orange carrots, for instance.

SIMON: I wasn’t initially trying to make it delicious. No. We were only looking at it from the standpoint of understanding the genetics of it. But, as we got going on this, there was some rumbling in the small-scale agriculture that there could be some interest in going back to these heirloom type of crops.

TWILLEY: This was in the early 90s. And there were a couple of things going on that made America ready for purple carrots. First, of all there was some hype about antioxidants.

SIMON: As we were moving along with that research, there was research in the nutritional sciences indicating that, hey, these purple pigments have a health benefit.

GRABER: The other thing that was changing in the early 90s? Farmers markets started to become far more popular. And small-scale growers wanted something new, something colorful to attract people to their stands. So one of Phil’s colleagues brought some purple carrots to Pike’s Place market in Seattle—

SIMON: And people were interested in them.

TWILLEY: Cautiously interested.

SIMON: He had slices these purple carrots and orange and yellow ones and he said that kids would pretty much readily taste them all. But he said some adults—not all—but some adults would pick up that purple carrot and then put it back down. They’d say I can’t eat that, that’s not the right color for carrots.

GRABER: But they did eventually try them, and the purple carrot started, slowly, to become more popular.

TWILLEY: Slowly. I mean, I wasn’t eating purple carrots in the 90s, I know that. Admittedly I was in England, which maybe wasn’t at the cutting edge in terms of carrot color..

GRABER: I wasn’t eating purple carrots in the 90s either, I really only started maybe some time the last decade?

TWILLEY: But the purple carrot renaissance isn’t just thanks to Phil—across the country, breeders were starting to develop new versions of these old colored carrots. Irwin remembers one of his colleagues, a guy called Leonard at Texas A&M, getting into purple too.

GOLDMAN: And he made a carrot actually that was purple on the outside and kind of yellowish on the inside. And he started to go to farmers’ markets to try to see if he could get people interested in it. And nobody recognized it as a carrot. So it’s really within this period of time that I’ve been working, the last 25 years, I don’t know, that there’s been an explosion of colors.

GRABER: And then there’s one carrot color that I haven’t yet seen around my farmers markets—a bright red carrot.

GOLDMAN: Which is more of an exotic color for carrots in United States, I would say, but is quite popular in Japan and China where the red carrot is used for new year’s ceremonies particularly or other special ceremonies. Red being a lucky color.

TWILLEY: Red carrots today are like purple carrots in the 90s. All the cool carrot breeders are working on them.

GOLDMAN: We’ve been breeding red. I’ve got some red carrots from Japan and China and we started breeding red carrots.

GRABER: But so far it hasn’t been going so well for Irwin with his red carrots.

GOLDMAN: Those are very, very poor tasting. They are really like—it’s been very depressing to me to not be able to break the linkage between the bitterness in the red carrot and the color itself.

GRABER: Phil’s had more luck. It still took him a while to crack the red carrot, because his new breeds started flowering too soon, and that meant the roots weren’t as sweet.

TWILLEY: But now he thinks he’s nailed it. So keep your eyes peeled for red carrots coming to a farmers market near you!

SIMON: Yeah, we are going to be releasing a couple of red carrots. I’m working closely with the Organic Seed Alliance.

GRABER: In fact some of you may have even seen red carrots released by other breeders already! These colors are beautiful and I can totally get why breeders love them and farmers who lay out their carrots at the markets love them. But is there any practical benefit, any reason I should choose a purple carrot over an orange one—like, is it better for me? Does one taste better than the other? Or is it all just for show?

TWILLEY: I am so glad you asked, Cynthia, because that’s exactly what we’re going to talk about next. Plus we’ll get into whether there’s any truth to the old wives’ tale about carrots being good for your eyesight.


TWILLEY: So, to answer your question, Cynthia, we need to get scientific about carrot taste evaluation.

SIMON: So we’ve done quite a bit of work on flavor and we categorize carrot flavor into only two categories. One is sweetness and that’s pretty obvious. And the other is what we call harshness, which most people would tend to call bitterness.

GRABER: These harsh flavors that Phil’s talking about, they come from chemicals called turpenoids.

SIMON: Some of the same compounds that account for things like the odor of pine needles. In fact hops flavor has turpenoids is in it. And, if you have too much of those chemicals in carrots, they’re very what we call harsh. If you have a lower amount then it’s a normal well-rounded carrot flavor, if it’s balanced with sweetness. And if you have too little, it doesn’t even taste like a carrot.

TWILLEY: Okay, so does one color carrot have more of these turpenoids than another? Or is one color always more sweet than the others?

GRABER: Phil says all colors of carrots basically taste the same—

SIMON: I mean they don’t all taste the same because not all orange carrots taste the same. But we’ve had a lot of debate within our group—should we say they all taste the same? They all taste like orange carrots, they have that same range of flavor.

TWILLEY: So the long and the short of it is that the color of a carrot has nothing to do with how it tastes. But does it have to do with how good it is for you?

GRABER: You all might have already heard about what carrots are most famous for—they have huge amounts of something called beta carotene.

GOLDMAN: In fact, a very, very small amount of a carrot is enough for your RDI for vitamin A. So it’s just really quite impressive.

TWILLEY: Beta carotene is literally named after carrots, because that’s where scientists first isolated it. And beta carotene is the raw material for Vitamin A. Your body converts beta carotene into the Vitamin A that you need for a whole bunch of things—your skin, your eyes, your immune system, reproduction—basically, to stay alive.

GRABER: Carrots are particularly known for their vision-boosting properties—you might have heard that eating a lot of carrots will help you see in the dark.

TWILLEY: Yeah. So this particular lie comes courtesy of my people, the British. Carrots are definitely important for eyesight—your eyes need Vitamin A. But seeing in the dark? No. What happened was that during World War 2, the Royal Air Force got the upper hand over the Germans thanks to two innovations—radar, which you know, helped them track the German planes, and also red lighting in the cockpit, which helped not blind the pilots.

GRABER: But the Brits didn’t want the Germans to know about their new, super high-tech advantages in the war. And they wanted to divert the Germans from all the new radar towers that were popping up along the coast. So instead, they spread the story that all these night flying pilots that were shooting down the Germans planes so well? They were finding their targets because—they ate a lot of carrots.

TWILLEY: To be fair, thanks to rationing, the British were eating a lot of carrots at the time—carrots were taking the place of sugar in a lot of desserts. But, yes, we lied. I’m sorry.

GRABER: And helped the Allies win the war. So, you know, thanks for lying.

TWILLEY: What makes this whole thing even more bizarre is the fact carrots have beta carotene at all is kind of a mistake.

GOLDMAN: First of all, all plants need beta carotene and they all have beta carotene in their foliage. So every green plant—grass, trees, everything—is full of beta carotene in its foliage. And you can see that beta carotene in the fall when the chlorophyll starts to degrade.

GRABER: The green chlorophyll masks the other colors in leaves. But when fall comes and the days shorten and the temperature drops, the green fades away, and you get to see all the beautiful beta carotene. Otherwise known as yellow and red and orange leaves.

TWILLEY: The leaves have all this orange in them because it’s their sunscreen. Beta carotene basically protects the leaf from sun damage.

GRABER: But it’s really weird that a colored chemical that protects leaves from the sun would show up in the roots! It was clearly a genetic mutation, a mistake. I mean, the roots are underground and never see the sunlight.

GOLDMAN: And yet, because they’re attractive and because people like the way they looked, they built up in root tissue through selection. And we therefore had colored, pigmented carrots. And so the fact that we get an incredible nutritional benefit from it as well as the visual appeal is just a beautiful thing.

GRABER: That nutritional benefit has recently become even more incredible. Breeders like Irwin and Phil have been mixing up the genetic material of carrots by breeding them—and they’ve managed something amazing. They’ve been able to pack even more beta carotene into these little beta carotene vessels in carrot cells.

TWILLEY: Fifty percent more.

GOLDMAN: It’s really amazing if you look at a modern carrot—the amount of beta carotene that’s present in the root is so abundant that it is in crystalline form. It’s almost as though it’s overstuffed.

TWILLEY: These orange pigments—the beta carotene—they’re also in all the cool multi-color purple and yellow carrots, too. But do those purple and yellow guys have other pigments with equally awesome health benefits? Which would maybe make them better for you than plain old orange?

GRABER: Well, so all the carrots have carotenoids, and of course carotenoids are great. All except the white carrots, that is. But the other colors, the red, the yellow, the purple, those do have some other chemicals. Red, for instance, it has lycopene, that’s the same chemical in a tomato.

GOLDMAN: The purple color is anthocyanin and anthocyanins are ubiquitous, you know. They’re in lots of fruits. They’re the color of the blueberries, for example, and they’re thought to be really strong antioxidants.

GRABER: Irwin says that the jury’s still out about how important antioxidants are for us, the science is going back and forth.

TWILLEY: But while we wait for the jury here, maybe purple carrots are the best? All that carotene and some groovy anthocyanins too? Or maybe the red ones with lycopene? Are they better than orange?

GOLDMAN: You know, I don’t think so. I don’t think that any one’s healthier than the other. I think the modern carrot today, the modern Western carotene carrot which is going to have lutein, beta carotene, alpha carotene in it, is extremely healthy.

GRABER: In short, they’re all carrots. They’re all great.

GOLDMAN: And I would focus more on how you cook it. And let me explain. The carotenoids are fat soluble, so they they will be much more bio-available if you have lipids in your diet. Maybe this is the argument for carrot cake. I don’t know. Probably it should be, right? That it has frosting, it’s got fat in it.

TWILLEY: Heck yeah carrot cake! Which is my favorite, and also a surprisingly recent invention—we wanted to tell that story this episode but we ran out of room, so we had to save it for our special supporters email. You can get that email if you support gastropod with $5 an episode on patreon or $9 a month on our website, gastropod.com.

GRABER: But to get back to cooking with carrots—cooking actually frees up more beta carotene, too. Cooking, and eating them with fats gets the most beta carotene. But then what about raw carrots?

GOLDMAN: I’m not saying people should stay away from fresh carrot because fresh carrot is great. I eat them all the time, like I have one with my lunch almost every day and I love it. It’s a great, crunchy vegetable. And there’s nothing wrong with it because you’re going to get a lot of beta carotene from that too.

TWILLEY: Obviously, Irwin is biased. He is a mega carrot fan. But are there any dangers to carrot consumption?

GOLDMAN: You know, the only one that that I’ve ever known about is one that you can get from particularly from carrot juice. I think it would be difficult to get it from raw or cooked carrot. But the phenomenon is called hypercarotenemia and hypercarotenemia is when your skin turns orange. You literally turn orange from eating too much carotenoid.

TWILLEY: This I had actually heard of because as a pasty, sun-deprived schoolgirl in England, the rumor was that eating lots of carrots would give you an attractive tan. I didn’t have the carrot commitment to actually test this out myself.

GRABER: I can assure you that the color is not actually that attractive. And you can indeed get it from eating raw carrots, not just drinking juice—I had a friend in college who ate so many bags of raw baby carrots that the skin of her palms turned this weird orange color.

GOLDMAN: But the good news about this is that there is no danger at all. There’s no health risk of hypercarotenemia aside from the social stigma of walking around as an orange person.

TWILLEY: Enough said.

GRABER: Great, good to know my friend didn’t do any lasting harm. But her story brings up another question: What are baby carrots?

TWILLEY: Are these carrots that we rip from Mother Earth’s arms too young? Are they yet another thing we ought to feel guilty about?

GRABER: We do have the answer, after a word from one more sponsor this episode.


TWILLEY: So far, we’ve talked a lot about carrot color. But carrots have other facets to their personality, too.

GOLDMAN: I would say the thing that sticks out most for you right away if you pull them up is the market classes— the shapes of carrot. And this is an interesting thing about carrot is that, depending on where you go in the world, there are accepted shapes of roots. So there are the Kurota carrots, for example, which is really, really popular in most of Asia. It’s a very sort of more triangular shaped carrot. If you go to parts of France and—well, many parts of Europe—you’ll see a carrot that looks more like a tube, It has a blunt tip and it’s called a Nantes type of carrot.

GRABER: Irwin says there are about 10 different shapes out there in the market. But what about baby carrots?

GOLDMAN: Baby carrots are both a blessing and a curse, I think, in the carrot universe. When I started this work, there weren’t baby carrots. They weren’t on the market.

TWILLEY: The time is the 1980s. The place is California. And the hero is a carrot farmer called Mike Yurosek. He sold his carrots under the brand Bunny Luv—LUV. Which you can still see in the stores today.

SIMON: He brought some broken carrots home, and I don’t know if it was him or his wife. But anyway somebody said well we should see if we can figure out what to do with these broken carrots, because we have to throw them away otherwise, if they’re bent or just didn’t grow long enough or ran into rock or hard place.

GRABER: Just like they are now, supermarkets then were super particular about carrots. Any ones that weren’t just the right length, shape, and color were basically just tossed out.

TWILLEY: Which was frustrating to Mike. So he wondered, what would happen if he took these misshapen carrots, and trimmed them down into smaller, prettier carrot bites. So he experimented. He trimmed some down into one-inch carrot chunks that he called Bunny Balls. Which you do not find in the stores today.

GRABER: But Mike also came up with another option—these were two inches long.

GOLDMAN: And I think they started by sanding off and rounding off the edges and making a little thing that looked —you know, that looked like a little baby carrot, but was in fact a big carrot that had been cut up into slugs. And that’s actually the industry term for them is slugs.

TWILLEY: Mmm. Slugs. But these slugs—called by the more consumer friendly name of baby carrots—they caught on.

SIMON: Initially these throwaway carrots were the ones used for baby carrots and very soon the growers got to saying, let’s forget about about using throwaways, let’s just grow these, because we can make three times as much from them. But almost half the carrots sold are baby carrots because apparently the effort of cutting and peeling a carrot is really huge.

GRABER: Phil and Irwin have been in the factories where they turn long skinny carrots into baby ones.

TWILLEY: It’s kind of an amazing thing to see—you can find videos online and we’ve got a link on our website.

SIMON: They basically roll them uphill over stainless steel rollers with grit on them and that peels them. It’s a very fascinating process to see those baby carrots come out of the other end of the line and it’s just a river of orange. It’s really fun.

GOLDMAN: And so then you’ve got this product that looks like a baby carrot and is quite beautifully orange and uniform and you put it into a plastic bag and you can use it as a snack.

GRABER: So baby carrots aren’t one of Irwin’s market shapes, of course. But it turns out that they have actually changed the shape of the carrots that are grown in the field.

TWILLEY: One of the ten commercial shapes grown today is a long skinny carrot called the Imperator.

GOLDMAN: And when the baby carrot came along the goal then became to grow a very long Imperator. And I’m talking here about something that’s almost maybe 14-16 inches long. And it—it really is grown at extremely high density. If you were growing carrots in Wisconsin you might grow them at say, 300,000 plants per acre. If you were growing baby carrots in California for a baby carrot pack, you might grow them at two million plants per acre. So it’s like growing—you know, they’re almost growing like pencils right next to each other to make a very very long thin thing that can then be tumbled and cut into it into chunks.

GRABER: Baby carrots have changed the economics of carrots, too.

SIMON: You and I are willing to pay three times as much per pound for them as whole carrots and so it’s been good for the carrot industry because it doesn’t cost them that much to make the baby carrots.

TWILLEY: It doesn’t cost them that much, they sell them for more, and… thanks to the baby carrot, we are all eating more carrots. In just the first year after the baby carrot was introduced in 1986, carrot consumption in the U.S. went up by around 30 percent.

GRABER: But then baby carrots got another boost.

TWILLEY: A company called Bolthouse Farms had bought Mike Yurosek’s company.

TIFFANY ROLFE: And so they came to us, talked to us about really kind of encouraging, getting, you know, younger people to eat more carrots.

TWILLEY: This is Tiffany Rolfe. She is in the advertising biz. She is currently chief creative officer at Co Collective. But she used to be in charge of creative at Crispin Porter Bogusky. It’s a big agency—they’ve done work for Mini Cooper, for Ikea, for Burger King. At first, Tiffany’s colleagues thought that carrot must be a code-name for a big client—like there was no way Crispin was really working on a campaign for carrots!

GRABER: But they were. So Bolthouse Farms had originally approached twenty other ad agencies before they met up with the team at Crispin, but they weren’t psyched about the campaigns those other companies came up with.

TWILLEY: I mean, there were fun ideas. One company had a baby carrot army storming a beach defended by junk food. Another had a carrot attacking a jelly doughnut, with the red jelly oozing out like a wound.

GRABER: At the end of the day, though, these ideas were all positioning carrots against junk food, basically telling people that you should eat carrots to be healthy.

TWILLEY: But health wasn’t selling. Especially not to kids. It’s not sexy.

GRABER: Tiffany’s company had done some previous work targeted at kids and they’d learned from that.

ROLFE: I had been a creative director on the Truth Campaign, which was you know to help bring down smoking in teenagers. And you know typical approaches in the past have been scare tactics.

GRABER: Tactics like—cigarettes can kill you. That didn’t work. And it didn’t work partly because teenagers saw smoking as a way of rebelling.

ROLFE: Our approach in that case was, like, let’s give them something else to rebel against.

TWILLEY: Tiffany’s idea was, let’s show the teens how they’re being manipulated by Big Tobacco, and let them rebel against that instead.

ROLFE: And that campaign worked to—actually, you know, more than any campaign in history—to decrease teen smoking.

GRABER: And so that gave Tiffany an idea. This time, she’d look at how teens are being manipulated by big junk food. Like Doritos.

ROLFE: At the end of the day it’s a, you know, over-processed corn triangle that has been marketed enough to make it seem much more exciting than it really is. And we can play that game too.

TWILLEY: So Tiffany and her team dissected exactly how all this over-processed corn was being sold to kids.

ROLFE: And our intent was to go more after the snackable baby carrot variety. Like, that wasn’t part of the brief, it was just carrots broadly, but we believed that the easier, snackable baby carrot was the carrot to lean into. And so we held up I think at one point a cheese puff and a bright orange baby carrot. And they kind of had a similar shape and even the orange from the carrot was brighter. And we sort of bit into a carrot and it was really crunchy and even crunchier then than the cheese puff.

GRABER: Tiffany and her team came up with a plan to market carrots basically just like a cheese puff.

TWILLEY: But with an edge. It’s like meta-cheese puff.

ROLFE: We wanted the self-awareness to be there, a bit of a jujitsu move. And so we had to be a bit more overt with it. We didn’t want to look like, oh, look, baby carrots is trying to be cool or wannabe and they’re copying. We wanted it to be very, very clear that it’s about exposing and sort of you know like being aware of what we were doing and we were on to the tricks.

GRABER: And then Tiffany took this plan to Bolthouse Farms.

ROLFE: And the more we revealed—and some of it was sort of crazy—it’s like you could see sort of the energy in the room, them kind of feeling like Wow, whoa, this is this is sort of exactly what we wanted, but like nothing we expected.

TWILLEY: Bolthouse Farms gave Tiffany the green light. And then the fun began.


ROLFE: And it’s funny because we were doing crazy things like—you know we were in a shopping cart and pushing the shopping cart off the edge of the cliff and shooting baby carrots like into the air and yelling “extreme baby carrots!” and then a pterodactyl flies through the air and eats a baby carrot. And it almost was like we couldn’t make it crazy enough. And we did one that was this futuristic version of baby carrots. And then we had this sort of luxurious sexy version of baby carrots.

GRABER: This is just like the Lindt chocolate ad we played in our chocolate episode! It sounded like you were about to get it on with the truffle. I love that they’re totally making fun of those kind of sex sells ads while still using sex to sell baby carrots.

TWILLEY: But the rebrand went beyond ads. The baby carrot needed new everything.

ROLFE: And so when we looked at—just like opened up our plastic bag of baby carrots that you had to kind of pull apart and it was kind of wet inside—didn’t feel that fun.

GRABER: So they researched other bag options.

ROLFE: And so we found a material that gave us kind of a chip bag quality.

TWILLEY: They switched up where the baby carrots showed up in the store— no more boring virtuous produce section. They even got these snack bags full of baby carrots into vending machines in schools—alongside the Doritos! They did everything Doritos does.

ROLFE: You know, so we did things like create the first mobile game that you could play by the crunch of a carrot. And we tested it against other chips that weren’t loud enough.

GRABER: They only rolled it out in a few cities, but, unsurprisingly, national reporters loved this campaign. It made the front page of The New York Times. Even Michelle Obama loved the idea of marketing carrots like junk food. That was the slogan Crispin came up with—”Eat ‘Em Like Junk Food.”

ROLFE: So it became a much bigger initiative than actually what you know we ended up investing in it initially to help get it to be thought of as this idea and spread.

TWILLEY: Those ads aren’t still around, the cool packaging isn’t either, but the baby carrot sales—they went up, across the country, and they’re still way up. Carrot consumption in America has more than doubled since the baby carrot first came along. And, today, 70 percent of those carrots? They’re baby carrots.

GRABER: And even though they’re back in the boring thin plastic bags, you can find baby carrots today in vending machines. Right next to Doritos.

TWILLEY: So all of this is amazing, right? But I am a cynical and hardened soul, and there has to be a downside to the baby carrot success story. What about all the waste from cutting out those baby slugs from the big carrot?

IRWIN: It was amazingly efficient. I have to say that there is a little bit of waste but I wouldn’t say that that waste is any different than the waste you’d have here cutting up carrots for dicing and slicing. So it is efficient. You could argue also that from a nutritional point of view maybe people ate less other things and they ate more vegetables. That’s great.

GRABER: But, if Irwin has a choice, he’s not going to go for baby carrots.

GOLDMAN: The downside to me is that these are not the most flavorful carrots.

TWILLEY: Irwin says the Imperator is just not the tastiest of carrot varieties in the first place. But also, the processing—the way the slugs are shaped—that actually also destroys some of the carrot’s nutrients and flavor.

GOLDMAN: And the sugar is right under the skin. So sometimes when you peel it, you peel off the very best part of the carrot. So.

GRABER: Plus, frankly, baby carrots are a little damp and maybe a little slimy when you first open the bag, and then they quickly dry out in the fridge.

GOLDMAN: And, also, they’re expensive. I mean if you think about you know buying bulk carrots and taking them home and washing them and peeling them—I always felt like how much work is that really? That said, I don’t want to be too critical of it because ultimately I’m really interested in people eating more vegetables and so I kind of feel like, well, this was a really creative way to get people to eat more vegetables.


TWILLEY: Thanks this episode to Irwin Goldman, Phil Simon, and Tiffany Rolfe. We have links to them and their work on our website at gastropod.com.

GRABER: Thanks again to Laura Heisler for bringing us out to Madison, Wisconsin, for the Wisconsin Science Festival—that’s also why we could taste Irwin’s delicious carrots, and his not-so-delicious wild carrots, in person! We have photos on our website, gastropod.com

TWILLEY: We’re back with a special bonus episode in just one week! So stay tuned.

GOLDMAN: Let’s look at these [RUSTLING SOUNDS] these are just harvested from that organic field. This is Bolero. This is the most popular variety in the United States for organic carrot production. And it’s beautiful. And they taste really nice. Is it good? It’s sweet, isn’t it? Yeah, that’s really nice.

TRANSCRIPT: The Incredible Egg

This is a transcript of the Gastropod episode The Incredible Egg, first released on October 23, 2018. It is provided as a courtesy and may contain errors.

MARY CASWELL STODDARD: Well, I guess, to many, an egg is a favorite breakfast food. But when I think about vertebrate animals, what stands out to me is that an egg really represents an amazing evolutionary invention.

CYNTHIA GRABER: Such an amazing evolutionary invention— and such a delicious breakfast food—that many of you have asked us to do an episode about them. And so that’s just what we’re doing!

NICOLA TWILLEY: We, of course, are Gastropod, the podcast that looks at food through the lens of science and history. I’m Nicola Twilley.

GRABER: And I’m Cynthia Graber. And recently Gastropod listeners Jessie Svet, Jeff Stoyanoff, and Benjamin Holloway all wrote in with egg questions. When did we first start eating eggs, and how did archaeologists figure it out? Which animals do humans eat eggs from, today and throughout history?

TWILLEY: What scientific mysteries does the egg still hold—or do we know everything there is to know about this incredible edible evolutionary invention?

GRABER: Is there still such a thing as wild chickens? And, if so, how are wild chicken eggs different from farm eggs?

TWILLEY: In fact, you all had so many questions that we can’t answer them all this episode—like the story of how we came to grow all our vaccines in eggs? We had to save that one for our special supporters email.

GRABER: Which you can get straight to your inbox if you support Gastropod at at least $5 per episode on Patreon or $9 per month on our website, gastropod.com/support.

TWILLEY: But in the meantime, we have more eggs than a Vegas breakfast buffet—plus answers to a bunch of your questions.


TIM BIRKHEAD: Well, one of the common questions that I’m asked is: Which came first, the chicken or the egg? And everybody that asks that thinks they’re asking it for the first time.

TWILLEY: This is Tim Birkhead. He’s a professor of zoology at the University of Sheffield, in the UK. And he wrote a book called The Most Perfect Thing: Inside (and Outside) a Bird’s Egg. So I think we know what his answer is going to be.

BIRKHEAD: Of course it’s eggs that came first because pretty well all organisms produce eggs. Birds evolved from reptiles and birds are in fact dinosaurs, they are a continuation of the dinosaur line.

GRABER: And of course dinosaurs laid eggs. Most reptiles still lay eggs.

TWILLEY: There are crocodile eggs. There are turtle eggs. There are snake eggs. They look a lot like bird eggs, and people eat them, although online reviews are mixed.

RAURI BOWIE: But one of the interesting things about birds is that the egg is very hard.

GRABER: Rauri Bowie is the curator of birds at the UC Berkeley Museum of Vertebrate Zoology.

BOWIE: So if you ever get the chance to feel a reptile egg like a crocodile egg or a lizard egg you’ll see that it’s much softer. It’s sort of leathery rather than having a much harder surface.

TWILLEY: A bird egg shell has an extra layer of calcium that makes it rigid. And that extra strength makes all the difference.

STODDARD: It was a very specialized egg with a shell that allowed vertebrates to colonize habitats away from water. And it’s this type of egg that that birds lay today.

TWILLEY: This is Mary Caswell Stoddard—she goes by Cassie. You heard her voice at the start of the show—she’s an evolutionary biologist at Princeton and her research is focused on eggs.

GRABER: Cassie explained that reptiles have always had to lay their eggs somewhere moist. That way the moisture in the environment around the egg can seep through the leathery flexible shell to provide water for the growing dino. But those first bird eggs that were hard, they formed a protective layer around the water already inside the egg. So this new type of egg could be laid anywhere, not just somewhere wet.

STODDARD: And when I think about that and try to reconcile out with the scrambled eggs on the plate—it does blow my mind still.

TWILLEY: So the egg really did come first—there would be no chicken, or any other birds for that matter, without the invention of the hard-shell egg. But I have a more basic question. Which is, what is an egg?

STODDARD: Eggs have a really specific role, and that’s simply to nourish and protect the growing chick up until it hatches.

GRABER: Cassie’s answer is a simple one, but it turns out that how the egg does that, how it nourishes and protects the growing chick, it’s actually really cool.

TWILLEY: OK, so I started us down this rabbit hole by asking what an egg is, but I just want to take a moment to warn you all that the natural history of eggs turns out to be quite amazing, and we are going to spend a minute explaining why.

GRABER: The shell itself is pretty amazing. It has thousands and thousands of pores, and those pores let oxygen in, which the developing chick needs. And they let carbon dioxide out. So basically the chick breathes through that shell.

TWILLEY: Different species of birds have completely different amounts of pores, and pores of different sizes, and no one knows quite why.

GRABER: Let’s continue traveling inward. Next is the albumen, and it’s watery, and that’s one of its main jobs—the egg white provides water to the chick as it grows.

BIRKHEAD: But it’s also a barrier so that if any microbes come down those pores, the microbes have got to cross this kind of albumin barrier. And the really striking thing about that albumen is that it contains almost nothing that a microbe could utilize. So I liken it to somebody trying to walk across the Atacama desert. It would be a very tough call for a microbe.

TWILLEY: It’s not just that the egg white doesn’t contain food for the microbe. It also contains active anti-microbials. The first one is called lysozyme. It was discovered by Alexander Fleming, better known for coming across penicillin. And you can also find lysozyme in tears!

BIRKHEAD: So initially it was thought that there might be just a handful of anti-microbials in the albumen. but we now know that there might be hundreds. There might even be thousands. And again that’s the product of natural selection working over thousands and thousands of generations. Because if the embryo becomes infected and dies then the genes for just don’t make it into subsequent generations.

GRABER: There are four different kinds of albumen. Some are more watery, some are more viscous. The closest denser kind of albumen is the type that forms those stringy bits you might see when you crack an egg.

BIRKHEAD: And their job is to suspend the yolk or the ovum in the central part of the egg. So each of those are attached, both to yolk at one end and to the shell membrane at the other end.

TWILLEY: I do not like these stringy bits when I find them in my scrambled eggs because they have a weird texture. But they are quite nifty because they make sure that whenever the parent birds turn the egg, the yolk also flips so that the baby bird is facing upwards. If it faces down, it dies.

GRABER: And finally, of course, perhaps the most business part of the egg of all: the yolk. It has all the nutrients that baby chick needs to develop into a full-grown bird.

TWILLEY: The eggs at the supermarket, they don’t have a baby chick in them, or even the beginnings of a baby chick—they’re unfertilized. But what you do see sometimes is a double yolk, which always feels a bit like winning the breakfast lottery.

GRABER: The double yolk is basically a biological mistake. The chicken releases two ova, those are the yolks, instead of one, and those two yolks get trapped inside one egg.

BIRKHEAD: In the wild, those eggs hardly ever hatch, because although they might have two ova, the amount of albumen doesn’t increase proportionately. And so basically those twins or triplets simply run out of water during the course of development and the embryos die.

TWILLEY: It’s also possible to get a no-yolk egg, although I never have.

GRABER: That sounds really sad.

TWILLEY: I have to imagine I would be devastated. I think egg-white only omelettes are the devil’s work. But fortunately, Tim says these yolk-free eggs are really, really rare. It’s another biological mistake—the albumen and shell form around a stray bit of tissue rather than a yolk.

GRABER: We’ve been exploring the anatomy of an egg. And there are also some pretty amazing things going on as the egg forms inside the bird, too. As we’ve started to describe, there’s an ovum, a yolk, and it travels down a tube and it gets surrounded by the egg white, the albumen, and then that gets surrounded by the membrane. And then that gets surrounded by a shell.

TWILLEY: The whole process of building an egg inside a bird takes about 24 hours from start to finish. The shell alone takes 12 to 14 hours to lay down using calcium nozzles, a.k.a. shell glands.

GRABER: And then come the spray paint. The spray guns inside the bird come in two colors, one’s greenish and one’s reddish.

BIRKHEAD: And by mixing those in different proportions and different concentrations the whole suite of all egg colors that we know can be created.

TWILLEY: Okay, I already was thinking eggs were pretty magical at this point—the antimicrobial in our tears, the little strings holding the yolk, all those clever pores—but this is the moment where they become drop-dead gorgeous, too.

BOWIE: One of the beautiful things about eggs is that no egg is exactly identical to another egg. And the reason for that is, the last phase of when a bird lays an egg is it goes in the shell gland, and that’s where the pigments are squirted on, and that egg’s rotated and it’s never quite rotated in the same way. So every egg is unique.

GRABER: You wouldn’t know this if you only looked at white supermarket chicken eggs, but eggs come in all sorts of different colors, and those colors are sprayed with all sorts of glorious ink-blot squiggly patterns. And then there’s one final step before the egg sees the light of day.

BOWIE: And then the final thing is to cover the egg with a kind of layer that’s equivalent to putting a layer of wax onto a car as it leaves the showroom.

TWILLEY: That final layer, that’s another defense mechanism to stop all those pesky microbes from getting in and feasting on the delicious, delicious yolk. Tim says it’s kind of like breathable Gore-Tex. And in America, in our infinite wisdom, we wash that layer off.

GRABER: Yay, we’re cleaning them! But this isn’t as great as it might sound.

BIRKHEAD: The unfortunate consequence of that is that when the eggs are washed, they are then dried, and the drying process actually literally draws in the water from the eggshell surface with the muck down the pores.

TWILLEY: And that can result in eggs getting infected with bacteria like salmonella.

GRABER: And this is why we in America store our eggs in the fridge. They’re not protected by that extra layer of Gore-Tex-like wax. And so they’re more vulnerable to infection.

TWILLEY: And in my home country, the UK, when you go into the supermarket looking for eggs, you’ll find them out on the shelf. Because they’ve still got their Gore-Tex on.

GRABER: Those supermarket eggs are pretty boring to look at, frankly. They come in white and brown, maybe a little blue if you’re lucky. But we wanted to see all those incredible patterns and even shapes and sizes that eggs can come in—in person.

BOWIE: We have about 14,000 eggs.

TWILLEY: Rauri, as we mentioned, is keeper of all the eggs! His official title is Curator of Birds at the Museum of Vertebrate Zoology at UC Berkeley.

BOWIE: And so what I’m going to take you through now is showing you some of the variety of eggs that we have in our collection and sort of some of the things that I think of as being very special, unusual.

TWILLEY: We started by looking at a drawer full of seabird eggs—auks, guillemots, puffins,

BOWIE: These are the same species but some of them have a more blue background. Some of them are very brown. Some of them are very white. Some of them have these really joined kinds of ink dot where the ink looks like it’s sort of run around. Some of them are much more finely speckled.

GRABER: Cassie’s looked at everything in the Berkeley collection and she has her own favorites.

STODDARD: In terms of pattern, I’d say that the jacana lays one of the coolest eggs out there. Jacana eggs are covered with these elaborate squiggles. And then I can’t not mention the tinamou. The tinamou are pretty drab colored birds themselves from Central and South America but they lay the most extraordinary glossy eggs that come in blue and green and even pink sometimes.

GRABER: Eggs come in an infinite variety of patterns and colors. And on top of that, they come in all sorts of sizes.

BOWIE: The largest bird that ever existed, at least that we’re aware of, is the elephant bird from Madagascar and it went extinct somewhere between 700 and 3,000 years ago. And we are very fortunate to have two elephant bird eggs.

TWILLEY: Remember, an ovum, the yolk, that’s a single cell. So the elephant bird yolk is also the largest single cell ever known.

BOWIE: You could fit over 100 chicken eggs in it. It’s probably about two to three times the size of the average human head. And then you know these are some of our smallest eggs. So these are—some of these are Anna’s hummingbird eggs.

TWILLEY: It’s like a cannellini bean.

GRABER: So eggs come in beautiful colors and patterns, and they come in all kinds of sizes. And eggs come in all kinds of shapes, too.

STODDARD: So owls, for example, tend to lay eggs that are almost spherical. They look a lot like golf balls. While other birds like hummingbirds tend to lay eggs that are more elliptical. and the hummingbird egg looks like a little Tic Tac. And some other birds like sandpipers tend to lay eggs that are highly asymmetric and pointy. So we see that variation and shape across the bird world.

TWILLEY: For generations, humans have marveled at all this variety. But Cassie wanted to understand it as well as appreciate it.

GRABER: She started with this question of shape.

STODDARD: Well, there are a lot of classic hypotheses about the evolution of egg shape. One of the popular ones was the idea that cliff-nesting birds might lay pointy eggs so that if the egg is bumped it will spin in a circle and not topple over the cliff edge. So that was one idea. Another idea is that egg shape might be related to clutch size or the number of eggs that a bird lays at a time. So some shapes might be optimal for incubation efficiency. Because eggs of certain shape might be optimally packed into a nest when there is a particular clutch size. And there were still other ideas that have hypothesized links between egg shape and a bird’s diet, or egg shape and egg strength.

GRABER: These are all hypotheses that needed to be tested. And Cassie decided to do that. She actually used the very collection that Rauri is in charge of in Berkeley.

TWILLEY: The Berkeley collection had recently photographed all their eggs and put the images online.

GRABER: Cassie created a computer program called an ‘Eggstractor.’

TWILLEY: Pun fully intended.

GRABER: And it extracts the shape of all those eggs. Cassie’s Eggstractor created a way to evaluate the eggs for two different shapes: how symmetrical or asymmetrical the egg is, and how elongated or round it is.

STODDARD: And so in this way we could actually create a map almost like an astronomer mapping the stars in egg shape space.

TWILLEY: And what that map enabled her to do was to try out all the various theories and see which fit the data best. So for example, Cassie looked to see whether birds that lay similar size clutches all cluster together in the pointy egg part of the map? But they didn’t.

GRABER: She checked whether birds with similar diets could all be found in the same region of the egg shape map. Nope. Or whether birds that lay their eggs on precarious cliffs and ledges had all evolved toward the same sweet spot on that egg shape map. Also no.

STODDARD: And we were surprised to find that egg shape is correlated with flight ability. We found that strong flying birds that migrate long distances like terns or spend their lives largely in the air like swifts, these birds on the whole tend to lay eggs that are also more asymmetric or more elliptical.

GRABER: Cassie has a theory for why the egg shape is related to the bird’s flight ability.

TWILLEY: As birds become more powerful fliers, over evolutionary time, they also become more streamlined.

STODDARD: So we think that as birds’ bodies over time became sleeker, this presented a challenge for birds because birds couldn’t lay eggs that were too wide across. And so one way to pack a large volume into an egg without increasing its egg width would be by increasing that egg’s ellipticity or asymmetry.

GRABER: So in Cassie’s new hypothesis, narrow, sleek strong fliers needed to lay skinnier, longer, or asymmetric eggs through their narrower, sleeker pelvis.

TWILLEY: Whereas owls, which are kind of chunky—they have round eggs like ping pong balls.

GRABER: This strong flyer-shape match seems to map onto the data in the broadest sense. But Cassie says it probably won’t explain all the variety in egg shapes.

STODDARD: When you zoom in on particular bird families or bird species, we expect that there will be different factors responsible for egg shape variation.

TWILLEY: Like, for example, Tim Birkhead’s favorite bird, the guillemot. Guillemot nests are covered in greeny-white poo—these birds are notoriously drippy shitters. Based on Tim’s research, the most likely explanation for the guillemot’s pear-shaped egg is that it helps keeps the blunt end of the egg out of the poo. This is still a theory, but it makes sense: the blunt end of the egg is where the baby chick’s head is—and where it comes out when it hatches—so keeping it clean matters

GRABER: Cassie’s theory is also still a theory, it’s just a correlation so far.

STODDARD: We need to do a lot more work to pin down whether there is a mechanism here that could explain why birds’ bodies and adaptations potentially for flight are correlated with egg shapes.

TWILLEY: But even though the egg shape puzzle continues, Cassie’s also looking at egg color. This is another area where there were lots of theories.

GRABER: Scientists have hypothesized that maybe the color has to do with how well the egg absorbs or reflects sunlight and heat. Or maybe how easy it is to find that egg in dark environments for cave-dwelling birds. Or maybe the colors are meant as camouflage. That’s one of the most popular theories.

TWILLEY: Cuckoos are famous for tricking other birds into raising their chicks. They fool the other birds by disguising their eggs to look like the eggs of the bird they’re trying to trick—they can make their eggs look like a robin’s egg, or a warbler, or whatever.

STODDARD: And so we have been trying to take a bird’s eye view in approaching this. And that’s important because birds see the world very differently than humans do. Birds have a fourth color cone in their retinas that’s sensitive to ultraviolet light.

STODDARD: So birds are tetrachromatic and we humans are mere trichromats, we have just three color cones.

TWILLEY: This means that birds can see up to a hundred times more colors than us. Unless you are one of the very, very, very rare humans who is a tetrachromat, in which case, I am so jealous!

STODDARD: And so we use a combination of spectrophotometery and UV photography, both tools that allow us to quantify colors in a way that is relevant to birds, to look at egg color and egg pattern in new ways.

TWILLEY: When Cassie looks at eggs the way birds would see them, she can pick out patterns that seem to be anti-cuckoo security devices—signatures that parent birds put onto their eggs to try to make sure they’re only putting their energy into raising their own chicks.

GRABER: But then on to another type of camouflage—are birds trying to hide their eggs from hungry animals that might want to eat them? Cassie has also created models for the ways that those predators might be looking at the eggs, too.

STODDARD: And it looks like some of our assumptions might not always hold up. It doesn’t look like egg camouflage is as straightforward as we thought.

TWILLEY: The defense of eggs is a complex thing. And it’s to do with structure as well as color. Because egg shells also have to be strong enough to be sat on by parent birds.

BOWIE: And I’ve done this—if you take an ostrich egg and it’s full, a 200 pound man can stand or woman can stand on the egg and it won’t break. If you jump on it, it’ll break but you can stand on the egg and it won’t break.

GRABER: But those egg shells also have to be fragile enough for a tiny baby chick to break out of. Cassie’s trying to figure out this mystery by studying the structure of the eggshell at the nanoscale. It’s just another one of the many questions that scientists are still trying to tease out when it comes to eggs.

STODDARD: So the egg presents a very good puzzle for researchers.

TWILLEY: But the egg is also delicious and makes a very nice breakfast. Or dinner.

GRABER: And we promise that we are now going to get back to the topic of food! Like—how long have we been eating eggs? But first we have a couple of sponsors to tell you about.


GRABER: Humans have been eating eggs for probably hundreds of thousands of years.

JULIA BEST: So we think other species such as Neanderthals, they were using birds definitely because we find the cuts of flint tools upon the bird bones. So we think they were probably using wild bird eggs. And even other species such as Homo heidelbergensis—there’s been egg shells found at sites that are 300,000 years old and associated with that species.

TWILLEY: This is Julia Best. She’s a zooarchaeologist at Bournemouth University in the UK.

GRABER: And we’re not just talking chicken eggs here.

ADELE WESSELL: So we have a really long history with eggs of all different kinds.

GRABER: Adele Wessell is a food historian at Southern Cross University in Australia.

WESSELL: In Australia, for example, Aboriginal people would have eaten emu eggs. In South Africa and Zimbabwe and places, people would have eaten ostrich eggs, duck eggs, quail eggs—basically, any kind of egg can be eaten.

TWILLEY: But actually tracing egg consumption in the past is tricky.

BEST: So our evidence generally comes from finding the very fragmentary crumbs of egg shell preserved in archaeological sites. And to do that we need to have a fun game called sieving lots of soil.

GRABER: And then they find tiny bits of eggshells. But you can’t look at those eggshell bits and just figure out what birds they came from, or what people were doing with them. So Julia has a few other tools up her sleeve.

BEST: So you can study egg shell under a microscope and, particularly if you put it under a scanning electron microscope, which is very powerful, you can look at lots of the tiny features of the eggshell.

TWILLEY: Remember we told you different eggs have different number of pores? Yeah you do! Well, Julia uses that information to identify her little egg shell crumbs.

BEST: We can for example measure the thickness of the eggshell. We can count how many pores are in it. And the internal surface of an egg shell has very distinctive little—they look like volcanoes, they’re the bit that the internal membrane clings onto. And these look different for different species. And so using a high powered microscope you can compare that to modern eggs and start to identify them to species. Which is great.

GRABER: But was that egg served for dinner, or did a little birdie hatch out of it? Julia can figure that out, too.

BEST: So as a chick grows within an egg it doesn’t just use up the yolk but it also extracts some of the calcium back out of the egg shell to help form its bones. And this leaves little pockmarks over the inside of the egg shell that I can then identify with the microscope.

TWILLEY: Julia uses all these tricks, and a couple more, to figure out when and where the domesticated egg-laying chicken entered the scene. Her question is: When did people start eating chicken eggs regularly, rather than the whole variety of wild bird eggs they might have enjoyed before?

BEST: So it really depends where you are. So, for example, in places like Iceland even when the chicken finally does become established there, you’ll still surrounded by a glut of wild birds so people still made use of the wild bird eggs.

GRABER: In England, when the chicken arrived, its eggs took over pretty quickly. And chicken eggs came to England with the Romans. Julia studied a 2000-year-old Roman amphitheater in the west of England for clues.

BEST: And at Chester amphitheater we found lots and lots of egg shell underneath the seating banks where people would have sat to watch the events going on within it.

TWILLEY: Julia analyzed them and she found they were chicken eggs, freshly laid.

BEST: So this shows that these were eggs being used as eggs and that people in that amphitheater 2,000 years ago were sat there probably having a snack equivalent having a pie at a football match today and then dropping their waste down under the seats. I like to think that potentially there was somebody sat outside the amphitheater flogging you an egg as you went in.

TWILLEY: It’s evidence like this that Julia can use to pinpoint when chicken eggs took over as the egg of choice.

GRABER: But we have not yet answered one major question that many of you have asked: Why the chicken? Why do we nearly exclusively eat chicken eggs today?

TWILLEY: The chicken’s wild ancestors came from the jungles of Asia. And that’s also where the chicken was first domesticated—we’ve talked about this before on Gastropod. Those wild junglefowl lay between a half dozen and dozen eggs once a year in spring. If you take those eggs away, they might lay another batch, but that’s about it. Domestic chickens, on the other hand—they lay three hundred eggs or more, all year round.

GRABER: It took a few different steps to get to those mega egg-layers. First, it looks like people in what’s now China domesticated chickens from those junglefowl as long as 4,000 years ago. And in doing so, they serendipitously disabled a gene that matched breeding to the length of the day. So originally birds timed their breeding to a specific time of the year. But with that gene disabled, the chickens were more likely to breed all year round.

TWILLEY: Even so, that genetic change wasn’t quite enough to meet our egg needs. Humans weren’t done messing with chickens yet.

WESSELL: Yeah. Well, one of the first things was the introduction of incubators so that you could breed chickens in separate sort of hatcheries. And the hatcheries then themselves would choose the strongest, healthiest kind of birds and different sorts of strains of birds for more efficient production—ones that laid more eggs, ones that laid eggs for a longer period of time, and so on.

GRABER: The Chinese and Egyptians figured out quite early on how to keep eggs warm and toasty and incubate those eggs more effectively. That’s great in terms of getting more chickens and then choosing the best chickens, but it doesn’t make those chickens pump out eggs all the time.

BEST: Where we see a big change potentially is later on when we get artificial lighting. Once we’ve got artificial lighting we can make hens lay more frequently because we can trick them into thinking that it is the time for laying.

TWILLEY: The first successful use of artificial lighting to increase egg production was in 1895, by one Dr. Waldorf. He built a chicken shed lit by kerosene and then later by gas, behind his house in Buffalo, New York.

WESSELL: There’s also, you know, adding vitamin D to their feed so that they don’t necessarily have to go outside as long.

TWILLEY: We’re not saying this is entirely a good thing—there are all sorts of problems with industrial egg production. We covered some of them in our episode last year called The Birds and the Bugs. But this is how we got to where we are.

GRABER: So now we have chickens that have been bred to be power layers. And we have artificial lighting that keeps them laying. And we have food supplements that keep them healthy indoors.

TWILLEY: And the end result is a lot of chicken eggs. That’s how chicken eggs became synonymous with eggs. Julia actually has seen this shift play out in the archaeology—she studied some sites in the Scottish islands where traditionally people ate a lot of seabird eggs.

BEST: And we see such a dramatic shift up there between collecting the wild bird eggs and then when the chickens come in, because you can get meat from all of the wild birds at many points of the year. But the chickens—they’re the ones that mean you can have eggs all year round.

GRABER: And now, now that the chicken won, and with all these advances in chicken laying technology, we eat a lot of eggs. In the U.S., today, on average we eat eggs three days out of every four.

TWILLEY: Collectively, we eat an incredible number of eggs every year, and we eat them in an incredible variety of ways. The egg is nothing if not versatile.

BEST: Even from the Roman period we have recipe books that show that eggs were being used in a really wide range of recipes.

GRABER: The Romans made all sorts of tasty-sounding dishes out of eggs, like one that had soft-boiled eggs in a pine nut sauce. They used eggs to make cheesecake. They used eggs to clarify wine. But not all the Roman egg recipes sound so great.

BEST: There’s a horrible recipe—well, it might have been delicious but it doesn’t sound it—for brain sausages, which describes mushing up some chicken brains with four eggs and various spices and forming them into a sausage. So there is a huge range of different applications for eggs even from some of our earliest written records.

TWILLEY: Binding, clarifying, poaching—eggs could do it all. But this is before artificial lighting, and before refrigeration—so eggs had one major Achilles’ heel. They went bad. So humans all over the world devoted a lot of ingenuity to preserving them.

WESSELL: So initially, you know, salting and pickling, those kinds of things would have been treating eggs and that would have made them available throughout the year, because sometimes you get a glut of eggs. The Chinese preserved eggs and I think a lot of people will probably be familiar with those tea eggs. So they were packed in kind of ash and lime and the egg shell just sort of slightly cracked.

GRABER: The famous Chinese century egg isn’t actually preserved for 100 years. And it won’t last for a hundred years either. Although the technique has been around for a few hundred years. The eggs are packed in a type of plaster that contains lime, the same ingredient in mortar and cement. And they cure for anywhere from about two to five months.

TWILLEY: At the end of that time the egg white is a dark, brownish black, translucent jelly, and the yolk is a super creamy greeny-blue color and it tastes really funky and really quite delicious—like a super stinky cheese. I actually much prefer Chinese century eggs to the pickled eggs you get in big jars in British pubs.

WESSELL: Yeah, they are really amazing aren’t they. I mean when you think about an egg, it contains everything that’s required to produce a bird. So there’s a lot of kind of nutrients in it but they also have particular sorts of properties.

TWILLEY: These particular properties—they are what has allowed the egg to embed itself in almost everything we eat.

WESSELL: I think you know cooking eggs really is is a lot about chemistry. So whether you apply heat, or whether you beat them or whether you mix them with fats and those sorts of things, they will kind of take up the different sorts of properties.

GRABER: One of the great things you can use egg yolks for is to bind together water and fat, which usually don’t stick together. This is why eggs are the critical ingredient to make oil and vinegar stick together in mayonnaise. The yolk contains special molecules called lecithins that bury themselves in the fat and also stick to water. So when you slowly beat in an egg yolk with oil and vinegar and some other ingredients, you get the white delicious creaminess that is mayonnaise.

TWILLEY: But eggs can also go from a liquid to a solid that you can cut with a knife, like a custard tart or a quiche. This is a cool trick where you use heat to unfold the proteins in the egg and then knit them back together in a different shape.

GRABER: And now onto another fun way to play with egg proteins. When you whip egg whites, you also unfold those proteins and get them to knit back together. And they capture tiny bits of air. You can use this trapped air to help lighten cakes. And obviously you can use it in a meringue—that is 70 percent air!

TWILLEY: We are not being sponsored by the egg board, I promise, but really—all that textural variety from one ingredient, it’s kind of amazing.

GRABER: Eggs are amazing from a chemistry standpoint. They’re nutritional powerhouses, too—after all, they have to support an entire developing chick. And they basically all taste good!

TWILLEY: Which is kind of curious if you think about it. Because in nature, if you taste good, other things want to eat you. And birds obviously would rather people and other predators didn’t eat their precious genetic material. So why don’t birds just put some kind of nasty chemical in their eggs to put the rest of us off?

BIRKHEAD: Well, the accepted answer to that is that if a female bird was to put distasteful substances into the yolk to deter predators, that might compromise the rate at which the embryo develops. And so there’s a kind of trade-off. I don’t think anybody’s actually tested that, partly because there are no distasteful eggs that we know of. So it seems not to have evolved.

GRABER: So now we know why eggs all basically taste amazing. But—do they all taste the same?

BEST: I mean a duck egg, you can definitely tell that it’s not a chicken egg. And I think quail’s eggs—they taste more creamy in a way. Now that might just be my modern mind saying I paid more for these therefore I’m going to enjoy them more.

TWILLEY: Duck, quail, goose—those are the only non-chicken eggs ones I’ve tried. You can find them in fancy shops. But Tim has tried something a bit more exotic.

BIRKHEAD: I ate usually scrambled gull eggs for lunch every day during the summer for three or four years and I used to swear blind to my friends that I couldn’t tell the difference with chicken eggs. And then a few years ago somebody gave me a clutch of infertile gull eggs and I ate them and there was quite a strong flavor to them so I was a bit taken aback. So gull eggs are a bit more chalky. They’ve got a slightly stronger taste.

GRABER: And then Tim has also tried another kind of seabird eggs—he’s tasted guillemot eggs.

BIRKHEAD: And guillemot eggs, if you boil a fresh egg, the white never sets in quite the same way as it does in a chicken egg. and it stays a kind of icy blue, slightly gelatinous and therefore not terribly appealing consistency but perfectly nutritious. They taste pretty good. but they do they do have a kind of slight, distinctive flavor.

TWILLEY: Ooh. now I’m intrigued. Icy blue and gelatinous? Distinctive-tasting how?

GRABER: Obviously you can’t just harvest wild eggs—it’s actually illegal, as Tim was quick to point out. He did eat them legally. But so what do scientists know about the different flavors of birds’ eggs?

STODDARD: This is an area of research in my mind that is still that is still wide open but of course difficult to test for for many reasons.

TWILLEY: As it turns out, not a lot of solid scholarship has been done on this issue. The Ancient Greek scholar Athenaeus ranked eggs by taste in his treatise on food. Peacock eggs came first, goose second, and chicken eggs were apparently a distant third.

GRABER: Cassie and Tim both told us the only recent research they could think of about the taste of eggs is from the 1950s—they were taste studies conducted by a British zoologist named Hugh Bamford Cott.

TWILLEY: Cott started down this path using egg taste test panels made up of animals—specifically hedgehogs, ferrets, and rats. You might wonder how a hedgehog can offer tasting notes on different eggs. But Cott set up an ingenious system where he put two dishes, each with a stirred-up egg from a different species, the exact same distance in front of each animal, and then recorded which it chose to eat. So, for example Pickles, one of the hedgehog tasters, he consistently chose wood pigeon eggs over blackbird, coot over owl eggs, and buzzard eggs over linnet.

GRABER: For Cott’s human tasting panel, he served three scientists omelettes from 81 different species. The penguin egg was considered gluey and without any flavor except some slight fishiness. The goose omelette apparently left all the tasters gagging, but Dr. Cott said the eggs themselves may not have been particularly fresh.

TWILLEY: Both Tim and Cassie said that Dr. Cott’s studies were not the most scholarly. Which means there is plenty of room for some new egg tasting science…

GRABER: Okay, are you ready.

TIM BUNTEL: Yes I’m ready.

GRABER: So we have three different types of eggs. We have brown eggs from chickens, we have blue eggs from chickens, and we have quail eggs. And what we need you to do is we need you to make three different little bowls of scrambled eggs and Nicky and I are going to see if we can taste any difference among these three different types of eggs.

TWILLEY: Yes, we ate eggs for science. Two kinds of chicken eggs and then quail eggs because that’s all we could find at the gourmet market.

GRABER: Oh, you’re weighing.

TWILLEY: It’s science, Cynthia.

BUNTEL: We have to be as accurate as possible here. Right.

GRABER: That’s my partner Tim, and he’s a great baker, so he loves to weigh ingredients. In this case, he wanted to make sure he had the same weight of eggs for the chickens as the quail eggs. After all, none of us had any idea how many quail eggs you’d have to crack to equal two chicken eggs.

BUNTEL: Okay. So what’s the plan? So you want me to cook all three and present them at the same time?

GRABER: Yes. And we won’t know which is which. And we’re just going to taste and see if they taste the same or different.

TWILLEY: And can I have a piece of toast with it?

GRABER: Nicky wants it to be lunch.

BUNTEL: And hash browns… All right, so this is the heirloom Andean blue egg. Not blue inside.

TWILLEY: Next up, two dark chocolate brown eggs from a French heirloom chicken variety called Marans. Apparently these were James Bond’s favorite eggs. As featured in From Russia with Love.

GRABER: And then we opened the package of teeny tiny very pretty quail eggs, which had brown squiggles on a cream background.

BUNTEL: All right. This is interesting. How am I to crack these?

TWILLEY: Have you ever cracked a quail egg before?

BUNTEL: I have never even seen a quail egg before, let alone cooked with them.

BUNTEL: Alright, let’s give it a little crack here. So tiny.

GRABER: Oh my goodness.

BUNTEL: It really looks just like a wee little egg inside.

GRABER: In case you’re wondering, Tim had to crack a full dozen quail eggs to equal just two chicken eggs.

BUNTEL: Okay, we’re going to go with one tablespoon of whole milk per batch here. I don’t want to cross contaminate the fork from scrambling. Now, you guys go away.

TWILLEY: I’m so hungry! I just wanted some eggs. But, science.

GRABER: I was starving Nicky until the science experiment was ready. Sorry.

TWILLEY: I must say, I was fully expecting there to be no real difference between all the eggs. I’ve eaten quail eggs before and to be honest I thought they tasted like eggs. But when Tim brought out all three bowls of scrambled egg, I spotted the odd one out right away.

TWILLEY: So just on color alone, I’m saying there’s already a difference.

GRABER: Whatever this green bowl is, it has a darker richer yellow color.

TWILLEY: Yeah and this blue bowl is a little lighter.

TWILLEY: Then FINALLY we got to eat.

TWILLEY: Blue bowl is quail for sure.

GRABER: I think blue bowl tastes different than the other two.

TWILLEY: The other two are more eggy and the blue that the eggs in the blue bowl are more creamy and less eggy. Alright, Tim?

BUNTEL: All right. The green bowl contains the brown egg. The blue bowl contains the quail egg. The white bowl contains the blue egg.

GRABER: So, two things: We guessed correctly which bowl had the quail eggs! It was a little lighter in color, and slightly different than the other two. To me it was more of a textural thing than a taste thing, but frankly I had a cold.

TWILLEY: It was pretty subtle. And the brown and blue eggs—they were both from chickens, just different color shells—and to me, they tasted exactly the same.

GRABER: Okay, so did we determine that that quail eggs are fundamentally different tasting from chicken eggs? Turns out that we hadn’t set the experiment up quite well enough to prove that.

STODDARD: Well, there certainly are differences in the amount of yolk that is in different eggs laid by different species.

TWILLEY: Cassie told us that as eggs get bigger, the ratio of white to yolk changes. The bigger the egg, the more white there is, proportionate to the yolk. So, in fact, the quail eggs could have had a creamier texture just because they had more yolk than the chicken eggs.

GRABER: This is something we should have included in the experiment design! Tim?

BUNTEL: Just don’t ask me in the future to actually separate the yolks in these tiny little eggs.

TWILLEY: This is what we need to do! If you portioned it out so we had the same ratios? Tim?

TWILLEY: Science in action, folks. We make the mistakes so you don’t have to. If you have the patience to separate out quail eggs and do this test right, be our guest—and let us know the results.

GRABER: Even if the ratio was the same, there are things that could change the flavor of the eggs. Tim Birkhead—not my partner Tim—he told us that what the birds eat might have an impact on the flavor. And that’s not all.

BIRKHEAD: It could also be that the female is secreting different combinations of chemicals into those eggs to serve different purposes.

TWILLEY: For example, one thing Rauri told us is that what order the egg was laid in makes a difference to what the mother bird puts in the egg.

BOWIE: What’s been shown in some species is that the egg that is laid last, she may put more testosterone into that embryo, which makes that baby more aggressive and assertive and so it catches up by being more more assertive in being fed. So there’s fascinating interactions between the lifestyle of the individual birds, what the female places in the egg, etc.

GRABER: Maybe that testosterone influences the flavor. Or maybe there are other chemicals that the mother bird puts in that we don’t know about yet.

TWILLEY: But also, maybe a chicken that eats the same diet as a guillemot would have an egg that tastes like a guillemot’s egg,

GRABER: But maybe not. The research has not been done.

TWILLEY: Scientists, get on it!


TWILLEY: Uh, Cynthia, I feel like we’re managed to make an episode on eggs and end up with the same number of questions as when we started, if not more!

GRABER: For all you listeners who still have burning questions—I guess we’ll just have to make another egg episode in the future!

TWILLEY: Thanks this episode to Rauri Bowie who showed us around the amazing egg collection at the Museum of Vertebrate Zoology at UC Berkeley. We have links to the gorgeous images of the collection, all digitized thanks to a grant from the National Science Foundation, on our website, so you can ooh and ahh at all the pretty eggs just like we did.

GRABER: Thanks also to Cassie Stoddard, Julia Best, Adele Wessell, and Tim Birkhead, whose book is called The Most Perfect Thing. And yes, that’s how we both feel about the egg, too. You can find links to their research and books on our website, gastropod.com.

TWILLEY: As well as a link to find out if you are indeed a tetrachromat, like birds. And finally of course thanks to Tim Buntel, egg cracker and scrambler extraordinaire. We’ll be back in two weeks with a brand new episode. Although frankly, we could keep going with eggs for ever.

TRANSCRIPT Marching on Our Stomachs: The Science and History of Feeding the Troops

This is a transcript of the Gastropod episode Marching on Our Stomachs: The Science and History of Feeding the Troop, first released on March 27, 2018. It is provided as a courtesy and may contain errors.

CYNTHIA GRABER: Okay, yeah, we want to try the egg.

NICOLA TWILLEY: I’m a little afraid. These are like golden yellow nuggets.

GRABER: They’re totally—these are egg corn puffs.

TWILLEY: Well, not corn…

GRABER: Or more like those little Styrofoam things.

TWILLEY: Styrofoam packing peanuts. But they smell like egg!

GRABER: Yes! Mmm.

TWILLEY: Taste like egg!

GRABER: Taste great. I mean, I love eggs.

GRABER: Mmmm, styrofoam packing peanuts that taste like eggs! But really, people, they tasted good. And we were surprised.

TWILLEY: Because they are the military food of the future. And frankly, rations don’t have a great reputation for deliciousness.

GRABER: You are listening to Gastropod, the podcast that looks at food through the lens of science and history, I’m Cynthia Graber.

TWILLEY: And I’m Nicola Twilley, and this episode we are enlisting our taste buds and heading into the lab to explore how the military gets fed.

GRABER: We get to the bottom of some important questions: Why have eggs made for soldiers’ rations always tasted so bad? Why is it so hard to make those perfect packets of protein portable?

TWILLEY: And does what the military eats actually matter? Can food win wars? Plus, from hot pockets to trendy cold-pressed juices, how does their food affect what ends up on our dinner tables too?



TWILLEY: Scrambled eggs was the first thing I ever learned to cook for myself. Eggs are still my go-to for the simplest possible last resort dinner when I’m tired and there’s nothing else in the house. Ready in minutes, delicious, good for you, and pretty much impossible to screw up, am I right?

GRABER: Exactly. But when it comes to eggs on the battlefield? Not so simple. Military food scientists have been trying to perfect eggs for decades, and they’ve been failing.

DAVID ACCETTA: This is a dehydrated eggs mix, butter flavored, and this was something that would have been made in a field kitchen. So instead of having to try to bring dozens and dozens of eggs up to the battlefields of the field kitchen, they would use these dehydrated egg mixes.

TWILLEY: That’s David Accetta.

ACCETTA: I was in Desert Storm, I was in the second Iraq war, I was in Afghanistan, a bunch of other different places. I ate a lot of MREs.

GRABER: Today David is head of public affairs at the U.S. Army Natick Soldier Research Development and Engineering Center. That’s a mouthful in itself. But one of the things they do at the Natick Center, as we’re going to call it for short, is develop the army’s food.

TWILLEY: So those dehydrated flaked eggs are grim. But they would be what you would get in field kitchens. They’re not the kind of food a soldier would carry with them to eat on the front lines.

GRABER: And, actually, David likes the dehydrated eggs.

ACCETTA: When I first came in the army and we were still eating the ones in the cans, the omelette in the can was also my favorite. And it was pretty easy because since nobody liked it, I could always trade whatever I had for it.

TWILLEY: Eggs in a can were an innovation in their time, as we’ll discover. But the army does not rest on its quest to make the perfect portable egg.

GRABER: The omelettes in cans were not a hit. So the scientists at the Natick center introduced a pouch version of an omelette—eggs in a bag. Because everyone wants eggs.

TWILLEY: The folks at Natick were very excited about their new veggie omelette in a bag. They took it up to Alaska to field test it on the troops there, and it performed well.

GRABER: But then they added it to the meal rotation. And everyone—well, let’s just say that the nickname for this veggie omelette was vomlette.

TWILLEY: If you look online, on soldier and veteran forums, there are a lot of feelings about the vomelette. One of the few description I can read aloud without wanting to vomlette myself is this one: “Opening the entrée packet is like walking into a stale egg fart in a thrift store dressing room.”

GRABER: So, not a huge success. Although David didn’t seem to mind.

ACCETTA: You know, it didn’t taste like a fresh omelet but it wasn’t, you know—it wasn’t bad in my opinion.

TWILLEY: It’s possible David may just be too fond of eggs to be a good judge. But so why has the humble egg defeated the mighty force of the U.S. military research and development team for so long?

GRABER: We asked Michelle Richardson, she’s a senior food technologist at Natick.

MICHELLE RICHARDSON: Well, number one, eggs have a very high pH. pH measures the acidity of the product.

GRABER: The lower the pH, the more acidic the food. And the more acidic the food, the more shelf stable it is.

RICHARDSON: Because bacteria can’t grow in it. I think eggs have a pH of 7. Think of tomato paste, which is very stable—it may have a pH below 4. So that’s the big difference.

TWILLEY: So pH is a problem. But why? We have to back up here, because part of the egg challenge is just that there are a lot of hoops any food has to go through to make it in the military.

JEREMY WHITSITT: Yeah, I think it’s all a big puzzle.

GRABER: Jeremy Whitsitt is deputy director for the combat feeding program. He laid the whole puzzle out for us.

WHITSITT: Because certainly nutrition and providing the right amount of calories is key. But doing it in a product that’s lightweight and low volume, that can sit on the shelf for at least three years, that can withstand being dragged through the mud and dropped out of aircraft and high temperatures, low temperatures. And then, at the end of the day, it’s got to taste good, because if it doesn’t taste good they’re not going to eat it so all that science doesn’t do any good anyways. And you’ve got all of those different factors kind of converging into this big puzzle and that’s really encapsulates our mission here is to make that puzzle come together.

TWILLEY: So like Jeremy said, these army-grade, pre-scrambled eggs have to be able to last three years without refrigeration. Whereas a normal omelette—if you left that out on your countertop, you wouldn’t want to eat it the next morning, unless you were really trying to give yourself food poisoning. As Michelle told us, eggs aren’t acidic enough to scare off dangerous microbes.

GRABER: And then there’s another problem when you try to process eggs for long-term storage. One way to kill off any potential critters is to heat foods to really high temperatures. And what happens to eggs?

RICHARDSON: A lot of times when you process eggs they turn green. Especially if you’re doing, like, high heat. They did have a retort egg in the MRE years ago, but it was one of the least liked items, so they had to remove it.

TWILLEY: Retort egg is not something you find on the menu at your typical diner. So we asked Michelle to explain what happens to an egg when it’s retorted.

RICHARDSON: So it’s put into this big unit and you have high temperature and high pressure to kill any bacteria in there. So that’s the sterilization process.

GRABER: Retorting eggs will turn them green. And retorting eggs, basically cooking them at high heat, it takes a long time to make them sterile. Many of you will know what happens when you cook eggs for too long…

TWILLEY: I have made this mistake. They turn into rubber.

RICHARDSON: You have textural issues that you need to deal with. And so when we process the retorted eggs, you have to add a lot of things to stabilize the texture, which may contribute to off flavors. So it was just very difficult to get something shelf stable that still tastes good.

GRABER: The egg challenge has bedevilled Ph.D. scientists literally for decades.

TWILLEY: Soldiers want eggs but for the most part they do not want rubbery green eggs that smell like a fart in a thrift store changing room.

GRABER: No, they most certainly do not. Which is why our tasting of those delicious dehydrated egg puffs was so incredibly revolutionary! They’re made using a new technology that you might have encountered at your local Starbucks.

OLEKSYK: Vacuum microwave drying is used currently to produce that moon cheese, for an example. But we’re taking it one step further and compressing it so that we get the dried product in a small compact space for rations.

TWILLEY: Lauren Oleksyk leads the food engineering and analysis team at Natick. And that moon cheese she’s talking about—that is that weird cheese puff snack thing they sell at Starbucks that’s kind of like a disappointing Cheeto.

OLEKSYK: It’s a vacuum microwave cheese. It’s a real cheese product just with moisture removed.

GRABER: This vacuum microwave drying works through a combination of vacuum pressure as well as microwave radiation. Together, the two approaches dry out food at a much lower temperature than oven drying, much faster. So more nutrients and flavors and colors are left in the final product.

TWILLEY: Basically, it’s a gentler process and so the food still ends up sterile, but also way more appealing and better for you.

GRABER: The samples we tried had just shown up in the lab that very morning, from a Canadian partner lab that specializes in this vacuum microwave drying technology.

TWILLEY: We were excited to try them. Michelle was too.

RICHARDSON: It does, it tastes nice. Has very nice egg flavor. I like the color retention, it’s hard to retain a yellow egg color after you process it. So that’s really nice.

GRABER: So maybe eggs have actually been solved?!

TWILLEY: And it’s only taken fifty years.

GRABER: Eggs are just one example of the ways scientists have been trying to figure out how to best feed the military for many, many decades now. But the question of how to feed soldiers goes back a lot farther in time.

TWILLEY: Back as far as Ancient Egypt. The first organized armies—this is four thousand years ago in Ancient Sumer—they fought their wars super nearby, so they could go home for dinner.

GRABER: But that didn’t work for the ancient Egyptians. They ended up with a territory covering 400,000 square miles.

ANASTACIA MARX DE SALCEDO: And they did in fact carry rations with them.

TWILLEY: Anastacia Marx de Salcedo wrote a book called Combat Ready Kitchen. She told us that Egyptian troops carried little cakes made out barley, some greens, and dried fish.

MARX DE SALCEDO: And this was so important, because it provided a portable protein, that it was actually part of their wages.

TWILLEY: This grain-onion combo continued to be the mainstay of military rations. In ancient Greece, the notoriously austere Spartans added some goat cheese and sour wine to the mix, but each soldier was expected to carry his own two-week grain supply at all times, which weighed at least 30 lbs

GRABER: The ancient Roman empire stretched across continents, and the armies had to be well fed to have conquered all that territory. They ate all sorts of cured pork products—prosciutto and bacon and sausage.

TWILLEY: Like the Egyptians, Roman soldiers were actually paid in food—salt pork specifically. Which took care of their salary, sodium needs, and dinner all in one go.

GRABER: The Roman army also ate Parmesan and other hard cheeses. They had a twice-baked cracker called hardtack.

TWILLEY: For thousands of years, military food stayed pretty much the same. Grain, some salty preserved protein, and maybe a little onion to spice things up.

GRABER: In case this isn’t totally obvious, solving the question of how to keep soldiers well fed is really crucial to any conquering army. The soldiers are working hard and sweating and they are probably not near a kitchen or campfire and they have to eat enough, and eat well enough, to not get sick and keep up their strength on the battlefield. Otherwise? You lose the battle.

TWILLEY: Or those hungry soldiers desert en masse because their priority becomes finding food, not fighting. And that way, you also lose the battle.

GRABER: Figuring out how to feed the military has always been pretty hard. Mainly because over the course of nearly all of human history, we haven’t had many good solutions for preserving food in ways that are also light and portable.

MARX DE SALCEDO: The reason that rations had not changed in millennia was because there were no new food preservation techniques. And so rations relied on drying, salting, curing, and smoking. And so even in as late as the French and American Revolutionary Wars, what soldiers were carrying in their rucksacks was pretty much the same thing as the Roman legionnaires almost 2,000 years earlier.

TWILLEY: And then everything changes. Thanks to Napoleon, some hot water, and a candy maker. Dinner—within the army and without—has never been the same.


MARX DE SALCEDO: During the French Revolutionary War there was a lot of hunger and starvation experienced both by citizens and soldiers, and this may have been the impetus. We do not know for sure.

GRABER: At the time, Napoleon was a young man rising through the military ranks. It might be because of the hunger he saw during the revolution, but, in any case, one of Napoleon’s top priorities when he became emperor was to figure out a better way to feed those hungry French troops. After all, he needed that army to help him take over all of Europe. So Napoleon offered a 12,000 franc award for anyone who could come up with a new, improved preservation method.

TWILLEY: Enter Nicolas Appert.

MARX DE SALCEDO: I like to describe Nicolas Appert as a bad boy celebrity chef turned candy maker. He decided to meet this challenge, and it turned out that candy making store was actually the perfect place to do so. And the reason was is that it has a lot of very specialized equipment.

TWILLEY: Because Nicolas was a candy maker, he already knew how to preserve fruit, by preparing it in syrups, jams, and jellies, inside sealed glass containers. So he decided to see if he could do the same sort of thing with other foods. He took vegetables, meat stews, peas, and beans and put them in sealed glass jars too.

MARX DE SALCEDO: And then he would put that glass vessel into a larger metal vessel with boiling water. This is actually a technique called the water bath.

GRABER: Another name for this water bath is a bain marie, literally Mary’s bath. The invention is attributed to a woman, to a Jewish alchemist. She is the first known woman alchemist, she lived in Egypt in the first century CE.

TWILLEY: So when you use a double boiler to melt chocolate or make a hollandaise sauce, you’re using a device invented in an attempt to transform base metal into gold! Which it does not do, but it is an amazing tool to hold the temperature steady at 212 degrees Fahrenheit—the boiling point of water—for as long as you want. Your food doesn’t overheat and burn and more importantly, it stays at that temperature long enough to kill all the microbes.

GRABER: Nicolas didn’t know about microbes, but he experimented. He put his jars of soups and stews into the bain marie…

MARX DE SALCEDO: And then he would cook the food for a period of time and then stopper up the bottle.

TWILLEY: And it worked!

MARX DE SALCEDO: Then he actually began to sell his products to the middle class in glass bottles and he called it “spring, summer, and fall in a bottle,” which is lovely poetic name.

TWILLEY: Once Nicolas had this process perfected, he brought his most delicious examples to the Navy, to see whether they would win him Napoleon’s big cash prize. And although it took the government a while, eventually he went home with 12,000 francs, in return for giving up the rights to his invention.

GRABER: But his invention relied on glass jars. It took an another guy to come up with an alternative—the tin can. Though even these weren’t ideal, because workers could only make six to ten tin cans a day.

MARX DE SALCEDO: So I don’t think it was something that was used except in the addition to the normal rations, and possibly for the officers’ mess, which is actually what happened in during the Civil War. Cans were only supplied to officers, and I believe it was canned condensed milk. And the regular enlisted men did not have access to this kind of food.

TWILLEY: So what about our candyman inventor? Nicolas Appert got the cash prize, like we said, and he used it to set up a bottling factory. For a while, life was good. He’s even credited with inventing peppermint schnapps, as an ice cream topping. But he had given away the rights to his best idea—the canning, not the peppermint schnapps—and his factory was trashed when Napoleon’s enemies invaded France.

MARX DE SALCEDO: Appert ended up dying anonymous and a pauper.

GRABER: What’s just as bad, or maybe even worse, is that you’ve probably never heard of Nicolas Appert, because he isn’t given credit for basically inventing pasteurization. That’s because he had no idea why his invention worked. Louis Pasteur discovered how microbes cause food to spoil and why the bain marie kills pathogens. That’s why this canning process keeps food safe longer. But Nicolas Appert discovered the process itself first.

TWILLEY: But today it’s pasteurizing, not Appertizing.

GRABER: It takes more than a century to get to the next big incentive to improve military food. And that’s World War II.

TWILLEY: Between 1939 and 1945, the military went from feeding just under four hundred thousand soldiers to having to provide three meals a day for more than 12 million recruits, stationed all over the world.

GRABER: By then the military had some new foods for the troops. They had this new ready-to-eat meal called the C ration, which was unappetizing grey stew in a can, in a single serving portion.

MARX DE SALCEDO: And it also had some dried rations, it had a chocolate bar which was called the D ration. And this was something that had been made to be deliberately unpalatable so that soldiers would use it in an emergency. These rations didn’t fare so well when they were shipped around the world. First of all, their packaging didn’t stand up to different climates and conditions. So the cans rusted, the cellophane on the D rations allowed water in and they became soggy.

TWILLEY: On top of that, soldiers complained that the fat in the C ration stew separated and went rancid, the meat tasted as if it had been cooked for months, the eggs and dairy smelled revolting, and the cans themselves were weighty and unwieldy

MARX DE SALCEDO: This was one of the reasons that the U.S. turned around and decided to invest a lot more in food science research during the war. So over the course of the four years of World War II, a small laboratory that really started as an ad hoc thing, with three employees, two of whom were former cooking instructors, one of whom was a secretary, a very small supply of battered equipment.

GRABER: That tiny ad-hoc lab was transformed. It became a huge research center, with around 300 employees specializing in chemistry and vitamins and packaging. They partnered with 500 university and industrial food science labs.

MARX DE SALCEDO: That whole system stayed in place after the war. And it became part of the policy of preparedness, so that we would always be ready at an instant’s notice to be able to enter a large multinational scrum such as World War II. So the Natick Center is a direct descendant of that system.

TWILLEY: And the Natick Center is where Cynthia and I were lucky enough to sample the military’s next-gen eggs. Eggs, like, 5.0?

GRABER: The research center was constructed in the 1960s, and it houses departments that are in charge of studying all kinds of things, like soldier’s clothing and shelter. But, of course, they also are in charge of what soldiers eat.

WHITSITT: So we do the research, development, test, and evaluation for food that our war fighters are eating either on the battlefield and in some cases in a garrison environment. So a dining facility and things like that.

TWILLEY: We’ve met Jeremy already this episode. He’s deputy director of the combat feeding program. And our first stop at Natick was actually him taking us on a trip backwards in time, through a little museum they have set up to showcase the unappetizing history of U.S. military food.

WHITSITT: Yeah, so this is kind of a walk through history, and it’s certainly not a comprehensive history of military rations, but I think you’ll get a good taste for it.

GRABER: Jeremy started us with the Revolutionary War — the soldiers ate hardtack, that super dry cracker, and preserved pork.

TWILLEY: Then there’s an entire section dedicated to that giant leap forward, the tin can.

WHITSITT: The can was was good against preventing moisture and bugs and things from getting into the food and making it go bad. But if you can imagine having all these cans kind of on your person and either in your rucksack or in your cargo pockets, and not only the weight but trying to assume like a quick position on the ground, those cans are like digging into your legs.

GRABER: Not the most comfortable.

TWILLEY: But that was the deal throughout World War II and even Vietnam: soldiers were expected to stuff up to 9 tins of food into their field jacket along with their grenades and ammunition. According to reports from the time, 2 out of every 3 cans were thrown away.

GRABER: Until 1980, when the can finally met its replacement. The folks at the Natick Center had been working on a can alternative forever, since 1959. It was their main priority. The researchers finally, after decades, managed to create a flexible foil-lined pouch that could be sterilized and hermetically sealed and ripped open at mealtime. This is it, people!

TWILLEY: This is the MRE. The meal-ready-to-eat, as it’s called in the army’s special C3PO way of talking. Woohoo! Mission accomplished. The team at Natick gave themselves a giant round of applause, job well done.

GRABER: And this flexible MRE was indeed great. But then, David says, the U.S. entered into the next major battlefield, this time in the Middle East: Desert Storm.

ACCETTA: So if you look at the initial invasion of Iraq in 1991, in Operation Desert Storm, and then again in 2003, there wasn’t time to stop and set up field kitchens and serve soldiers and Marines hot food. So they ate MREs and that was the only thing that they had, and if they had to eat them three times a day then they ate them three times a day.

TWILLEY: But the problem was, they weren’t eating them. These new MREs might have been lighter and easier to carry thanks to the revolutionary flexible pouch, but there were only twelve different menus. Which led to problems that the Natick team diplomatically referred to as “menu fatigue.”

ACCETTA: Even if you liked all twelve, you were going to eat the same thing over again within a period of three or four days.

GRABER: But the troops weren’t eating them all. Once again, they were throwing a lot away. That meant they just weren’t eating enough food. Or if they did manage to scrounge through the package or trade to get snacks that they liked, they weren’t getting the nutrition that they needed. The army says the troops were suffering physically and cognitively.

TWILLEY: Boredom wasn’t the only reason soldiers weren’t eating their MREs. It was also because they frequently had to consume these meal pouches cold.

GRABER: It’s because they had to use fuel tabs to heat up water. Lauren Oleksyk told us that the fuel tabs couldn’t be packaged with the food, and so they didn’t always show up in the same place at the same time as the MREs.

OLEKSYK: Really, there was no way of heating that food in the field. They can eat it cold. But from a morale standpoint, from an acceptability standpoint, they like it much better when it’s heated.

TWILLEY: So yeah, cold meatballs in marinara sauce from a pouch three meals a day—I think I’d end up deciding it was better to be a little hungry sometimes, too.

GRABER: So now the team at Natick has a new huge challenge ahead. They have a lightweight foil pouch. But how can the team create a new way to heat the food that can be packaged with the food, so that the people in the field won’t be stuck in a situation where they have fuel bars but don’t have their MREs, or they have their MREs but the fuel bars didn’t make it?

TWILLEY: And beyond this thermal challenge—how did the fact that all these soldiers were throwing their pouches away, uneaten, lead to a whole new era of shelf-stable hot pockets and even military pizza!


TWILLEY: So here’s our situation: The food is cold. This does not help with quote “palatability.” The army needs another breakthrough. They get to work after the first Gulf war, and in 1993, which is kind of record-breaking speed for the military, they came up with a winner.

ACCETTA: So the flameless ration heater allows them to have hot food anywhere that they are, because all you need to do is add water and it’s an exothermic reaction. And we just happen to have with us here Laurie Oleksyk, who was instrumental in the development of the flameless ration heater.

OLEKSYK: So this is a very small lightweight chemical heater that is magnesium and iron-based. And when the soldier is ready to heat up his main entree, he slides the flexible pouch down inside of this bag and adds water up until the fill lines. And within about maybe four or five minutes, the heater starts to activate and it just produces heat and steam and will heat the entree up till about 140 degrees Fahrenheit—a good serving temperature—in about eight minutes

GRABER: A company called ZestoTherm in Ohio had developed this technology as a heating pad. Lauren adapted it for the military. Basically, as Lauren said, it works by combining magnesium and iron, and then you add water in the field.

OLEKSYK: The natural reaction of those elements is to produce heat. But it doesn’t produce heat very quickly, so we added salt as a catalyst for that reaction and it takes off fast.

TWILLEY: All this talk of magnesium and iron was making me hungry. Plus we wanted to experience some of that steam heat for ourselves.

GRABER: So we decided to have lunch—army style.

TWILLEY: David used his pocket knife to open a big cardboard box full of MREs

ACCETTA: Okay, here is your vegetarian meal. Menu number three: vegetable crumbles with pasta in taco-style sauce.

GRABER: Sounds fun, yeah.

ACCETTA: Does that sound like a winner?

GRABER: Okay, yeah maybe.

TWILLEY: What am I going to get?

ACCETTA: You get lucky, you get spaghetti and meatballs in marinara.

GRABER: Oh, you get the one they all want. Nicky, you apparently scored big time.

TWILLEY: Yep, David told us that meatballs is the most popular entree out of all 24 MREs.

ACCETTA: Okay, so…

TWILLEY: Inside the foil pouch was not just our veggie crumbles and marinara meatballs, but a whole bunch of other little foil packets filled with random things to eat. It was kind of like a stocking on Christmas morning. Italian breadsticks…

GRABER: Jalapeno cashews.

TWILLEY: Teriyaki beef stick.

GRABER: This is my—I don’t know, this doesn’t say anything.

GRABER: That mystery was actually a pouch of cooked pears. There was an oatmeal cookie, a powdered drink, jalapeno cheese spread, something called a first strike energy bar… Ooh and I got chunky peanut butter! Yum.

TWILLEY: I’m jealous of that

ACCETTA: It’s for your crackers.

GRABER: Awesome.

ACCETTA: Now one thing that you have to keep in mind is that these are designed for troops in a very active environment. So you’re looking at 12 to 1500 calories if you eat this whole thing which is more than a sedentary adult might need in one day.

GRABER: You’re saying that we’re not as active as the military? I don’t know here.

ACCETTA: I’m saying that I shouldn’t eat this whole thing at one meal.

TWILLEY: At this point, our stomachs were rumbling. It was time to bust out Lauren’s secret weapon, the flameless ration heater.

ACCETTA: Alright, and then you want to make sure that the water is circulating around and gets to the pad that has the iron and magnesium powder in it.

GRABER: Does it feel warm to you yet.

ACCETTA: Not yet, it’s going to get there. And once it activates you’ll start to see.

GRABER: Oh, the steam. Oh my gosh. It’s steaming, Nicky, take a picture.

ACCETTA: I don’t know if you can—if the microphone will pick up on it—you can hear it.

TWILLEY: Yes, you certainly can hear it! That’s the sound of flameless ration heater steam!

GRABER: I know the whole point of this flameless heater is that it heats up the food, but it was kind of shocking how quickly it got too hot to touch.

TWILLEY: While we waited the eight minutes Lauren had recommended, we snacked. So I’m opening my—wait, what did you call it? Dehydrated bread concept.

ACCETTA: It’s shelf stable.

TWILLEY: Shelf stable bread. Like the well brought up individual I am, I shared my Italian breadsticks with the table.

TWILLEY: So this is not bread but it’s also not not bread.

GRABER: It’s kind of like a soft thick cracker.

TWILLEY: Yeah. Soft and thick and still quite… moist.

GRABER: So the creation of this shelf-stable soft-ish bread was a major innovation over the hardtack of centuries past. But I have to admit, we didn’t love it. Okay, so I’m going to try my um…

TWILLEY: Oh yeah.


GRABER: It smells totally like the kind of taco pasta veggie fake meat thing.

TWILLEY: And now you have some on your microphone.

GRABER: Oh I do. It tastes like, you know, those cans of like veggie pasta and kind of fake meat stuff that I would have eaten early on in my vegetarian days. It’s totally tasty.

GRABER: Now that I’m not sitting next to the people who work on this, I can admit that it wouldn’t be my first choice or even my second choice for lunch. That said, it did really taste like something I would have eaten decades ago from a can.

TWILLEY: My problem was that my expectations had been raised. Meatballs are the troop favorite. I was expecting something a little… frankly, tastier.

TWILLEY: Little meatballs, orange sauce. Mmm. Probably should have heated it up a little bit more but totally edible. There’s an interesting after-taste—let me put my finger on it…

GRABER: I didn’t try your meal, but, Nicky, it was clear that you didn’t love it.

ACCETTA: if you are sitting in a building at a table and you’ve got heat and you’ve got electricity and you’re eating your MRE, you may not appreciate it in the same way that you would appreciate it if you were cold, wet, tired, and hungry and sitting in the dark in the rain on a mountainside in Afghanistan.

TWILLEY: David is trying to say in the nicest possible way that Cynthia and I are spoiled brats. Point taken.

GRABER: But the other point is that these are huge improvements over the MREs that people ate during Desert Storm. And innovating in new food products, and making MREs tastier and more healthful—that’s all still going on today.

TWILLEY: Including years of R&D to develop the holy grail of rations: shelf stable pizza

OLEKSYK: For Michelle, the pizza was the most desired and asked for product in the MRE. And she tackled that, every challenge that came along with developing that pizza and stuck with it until we overcame every single hurdle.

GRABER: Michelle Richardson spearheaded the pizza development research.

TWILLEY: As a civilian, pizza for dinner seems like the lazy option, but pizza was full-on egg-level military food science nightmare.

RICHARDSON: And when you come up with this idea to give them the pizza, but then you put all these different things—we have the cheese, we have the pepperoni, we have the sauce, and we have the bread. And they all have different characteristics when it comes to water activity and pH.

GRABER: Let’s start with water activity. Imagine leaving pizza out on the countertop. It gets soggy.

TWILLEY: Michelle says the first thing the team had to do is to control the water activity in the pizza. The problem is that water wants to migrate from the wetter ingredients like sauce and cheese, to the ones that you would like to keep dry, like the crust.

RICHARDSON: So if you have a bread with a water activity that’s very similar to the water activity of the pepperoni or the cheese, you can kind of control that migration because the migration is based on the water activity difference. And so we try not to have a big gradient, so you don’t get that migration.

GRABER: How does Michelle make sauce that has the same water activity as a much drier bread? With something called humectants. These are incorporated into the sauce, and they bind to water to keep the water in the sauce and away from the bread.

RICHARDSON: And we use different things, like, rice syrup is one of the components. Salt is an excellent, probably one of the best humectants. However it would also contribute to the flavor. So it’s like a balancing act. And so we use things like glycerol, which is the backbone of a fatty acid and a major component of a lot of foods and candies nowadays. And so by looking at different concentrations of those ingredients, we’re able to lower the water activity in the sauce

TWILLEY: Success! But it’s not enough that the pizza doesn’t go soggy. It also has to stay good for 3 years without refrigeration. All that lovely moist cheese and pepperoni—it has to not grow mold or bacteria.

GRABER: To stop the pizza from becoming a food poisoning nightmare, the team uses something called hurdle technologies.

RICHARDSON: And you can think of hurdle technologies as a series of barriers that you can put into food to prevent the growth of bacteria. And so what we looked at is different technologies, all different hurdles that we can incorporate into the food.

TWILLEY: Michelle told us that she played around with a lot of different ways to reduce microbe growth without messing up the taste and texture.

RICHARDSON: We’ll use preservatives. And you know, we try to use natural preservatives. In the shelf stable sandwiches, we use things like mold inhibitors, yeast inhibitors, and things like that. We also use pasteurization, we consider the baking step a pasteurization step. Then we also use packaging as another hurdle. So. The idea is that one of these alone will not make the food stable, but in combination it will.

GRABER: The MREs are supposed to last three years in the field. But luckily Michelle doesn’t have to leave her packaged pizza out for three years to make sure it’s still tasty and safe to eat. They’ve developed ways to mimic that three-year time frame. They make sure that no undesirable microbes are growing, and that the pizza hasn’t collapsed into a soggy mess.

TWILLEY: This shelf life testing is one of the last steps for Michelle, but, at that point, pizza was still not ready for prime time. Next it had to be taste tested in the field.

GRABER: Pizza is one dish that people have been practically begging for. And after Michelle worked on the pizza conundrum for five years with lots and lots of iterations, this version has aced both the lab safety and the field taste tests.

RICHARDSON: And I think besides pizza, beer is one of the other things they want, and so we were actually happy when we actually able to solve this problem and give it to them. This will probably go into the next MRE.

TWILLEY: Pizza may finally be solved, but the work is never done. In the same lab as Michelle—the food engineering and analysis lab—there are all sorts of scientists working on all sorts of weird future ration concepts.

OLEKSYK: They call this the Willy Wonka lab.

GRABER: Hopefully nobody will blow up into a big purple.

GRABER: We walked around the lab with Tom, Michelle, and Lauren—no, nobody was blowing up into a giant purple bubble—and they showed us 3D-printed food on demand. They’re checking out a new microwave sterilizing technology that’s faster than boiling pouches in water, so the food keeps more of its flavor and nutrition. We tried those egg puff bites. The eggs won’t be in the MRE in the near future, but hopefully soon. Senior food technologist Tom Yang worked on those. And he has a few more projects in the pipeline.

TOM YANG: This is a French technology. I happened to encounter this technology also was about fifteen years ago.

TWILLEY: The particular problem that was bothering Tom fifteen years ago is the jerky problem. The way to make jerky is by soaking meat in brine. Which is a problem already because the Natick team wants to keep sodium levels down.

YANG: So it’s very salty. And after we store the regular jerky for two three years, become very brittle.

GRABER: The fibers in the meat get more and more tightly bound together over time and the jerky gets too crunchy.

TWILLEY: So this French technology Tom came across—again, fifteen years ago—it’s called Osmo Food. And the way it works is that it uses a sugar solution—maltodextrin specifically—to lure some of the moisture out of the food.

YANG: You grind up the meat, any meat. Beef, pork, chicken, ostrich, goat meat, whatever or even fish. Grind it up and extrude it to a sheet like a fruit roll up, very thin, 2 mm thick sheet and go through these osmotic tank which contained a sugar solution but very concentrated.

TWILLEY: The sheet of meat comes out of the tank in a condition that Tom calls semi-moist.

YANG: And it’s versatile. We try it, after two or three years is still soft and juicy, not like a conventional jerky is very hard like a rock.

GRABER: We didn’t actually get to taste this product, so we were just going by Tom’s description. But I think our favorite project of Tom’s was his salad bar.

TWILLEY: I’m so intrigued by the salad bar.

YANG: You can munch it. This is balsamic vinegar.

GRABER: Wow, that’s good!

YANG: Flavorful.

TWILLEY: A salad MRE? Whatever next?!!

GRABER: If only. These salad bars weren’t not exactly that. They were freeze dried.

TWILLEY: The military actually invented freeze-drying back in World War 2, but they don’t use it a lot at Natick—it’s too expensive. And actually if you freeze dry just a solo vegetable, it becomes woody and tasteless.

GRABER: So Tom first marinates his vegetables in different flavors of salad dressing before he freeze dries them into a bar. It definitely improves the flavor.

TWILLEY: And then he wraps his marinated freeze-dried salad mix inside these groovy vegetable-based wrappings that Michelle found for him, and ta da, a salad bar.

GRABER: So now Tom knows his salad dressing-wrapper trick works and tastes good. But because freeze drying is expensive, Tom’s looking for a new process to make his salad bar. He thinks maybe vacuum microwave drying is going to be the way to go. That’s what they used on the eggs puffs we tasted. I’m guessing it’s going to be a few years before this salad bar is in the field.

TWILLEY: All this weird vacuum microwaved egg puffs and freeze-dried salad bars and fish roll-ups—they’re not just about making military food taste better and be more nutritious.

WHITSITT: The demand signal that we keep getting from the force is: we want it lighter, we want it lower in volume. We want to be able to stick our guys out in some forward operating area for seven days without resupplying them.

GRABER: Jeremy Whitsitt is deputy director for the combat feeding program, and he wants to make sure that the people in the field get just what they need. Because today’s wars are different from the wars of the past.

TWILLEY: When the generals lay out their vision for the future of war, it doesn’t usually include details such as what the troops will be eating. But dinner is a detail that actually matters. Jeremy told us a story about a bar his team had developed for the 82nd Airborne. That’s a parachute division, and they’d been seeing a bunch of injuries on their jumps.

WHITSITT: But the idea is sometimes these guys haven’t eaten for six to eight hours before they’re getting ready to jump and it’s kind of a mentally rigorous task that they’re asked to do. So they were theorizing that hey, maybe it’s a lack of food or lack of nutrition. They’re kind of making these little mental mistakes that are increasing the static line injuries.

GRABER: So researchers at Natick took their super energy dense first strike bar, which has a lot of calories in it. And they added 200 milligrams of caffeine to it. Because caffeine obviously helps with concentration.

WHITSITT: We made those in-house, about 5000 of them, and delivered them to 82nd Airborne. They jumped into Poland and Germany with them and about an hour before they were due to jump, each soldier would take it out of their cargo pocket or their sleeve pocket, eat it.
And it’s anecdotal evidence at this point, but the amount of injuries they had dramatically decreased and they’re attributing it to the fact that these guys were able to eat an hour before.

TWILLEY: There’s a saying: an army marches on its stomach. But sometimes we forget how much it matters that the troops are properly fed.

GRABER: Nicky and I might have seemed a little picky about our lunch, but, really, the meals today are way better than the ones in the past. And they’re better balanced, too. It’s not just making sure the troops get as many calories as they need, but scientists are also focused on the overall nutritional balance of the meals.

TWILLEY: Admittedly, they’re mostly adding those vitamins and micronutrients by fortifying heavily processed foods rather than through finding a way to serve whole foods—but they’re trying. Look at Tom’s salad bar. The thing is that it just takes forever to engineer food that can meet the military’s unique challenges.

MARX DE SALCEDO: I actually am going to take my hats off to the Natick Center, because I think that the fact that they have been able to create a ration system that is nutritious, portable, rugged, can be shipped halfway around the world, can last up to three years at room temperature and can help soldiers survive in the field and in battle is remarkable. And has been a competitive advantage for the United States during military engagements. So yes, it’s a competitive factor and it’s been very important.

GRABER: That’s Anastacia—again, she’s the author of Combat Ready Kitchen. And she says not only have the breakthroughs at Natick been critical for the military, but these breakthroughs have transformed what we can find on our supermarket shelves. In fact, the subtitle of her book is “How the U.S. Military Shapes the Way You Eat.”

TWILLEY: So we asked her to walk us around an imaginary supermarket and show us some of the foods the military has had its hand in. We started off in the produce department.

MARX DE SALCEDO: One of the things is the packaged greens and salads that people like to buy. I know I certainly do, because you don’t have to clean them and we Americans hate cleaning anything. So the technology there is modified and controlled atmospheric packaging, which was developed during the 1960s to better preserve things like lettuce and celery to send to Vietnam.

GRABER: That’s one example. And remember those breakthrough foil packages? You’ve probably used them, too. Think about Capri Sun, or tuna in a pouch—all of that is only possible because of the military.

MARX DE SALCEDO: If we move into the meat section, there actually two—at least two major influences. The first is something no one would think of, which is that the meat is served cut off the bone and packaged in the different cuts. And that is actually goes back to World Wars I and II, when the the military got the idea that it would reduce costs if they didn’t have to ship over carcasses, and instead started to slice meat off at the point of slaughter and pack it up into boxes. And a final meat product would be the high pressure processing, which is also used to create lines of preservative-free deli products.

TWILLEY: This high-pressure processing—on labels, it’s sometimes called cold processing, because it doesn’t involve heat—it is a fancy way of sterilizing food and it’s also the trick used to keep those shelves of expensive fresh juices good for days.

MARX DE SALCEDO: Next aisle I’m in, let’s say I’m looking at some freeze-dried coffee and tea.

GRABER: As we mentioned earlier, freeze-drying was developed by the military, though it never really took off there. And then Anastacia walked us over to the bakery aisle.

MARX DE SALCEDO: That relies on a military breakthrough called intermediate moisture food, which is created by knowing how to control and predict something called water activity, and allows you to create moist and chewy things at room temperature. So all sorts of cookies. And of course our beloved granola bars. Again in that aisle you might have supermarket bread, which is kept soft and fresh for weeks by virtue of an enzyme that is supplied by a heat-resistant bacteria. The idea for this again came from the military during the 1950s, when they were looking for a way to create a canned bread.

TWILLEY: All of the pepperoni hot pockets and those cheese-filled combos snack things and those pre-made PB&J Uncrustable sandwiches: all of those are made possible by the same techniques Michelle used for the military pizza. It’s about stopping the water in the soggier ingredient from getting into the drier crust. That plus the enzymes that keep the bread soft forever.

GRABER: And now we’ve made it to the check-out counter. There you might find some Pringles, they’re made of dehydrated potatoes using a method developed by the military.

TWILLEY: And you’ll probably also see M&Ms, which were developed during World War II as a way to give the soldiers chocolate that wouldn’t melt.

MARX DE SALCEDO: When we get to that checkout counter and look back at the store, if we were removing all items that had a military origin or influence, I estimate that the store would be half empty at least.

GRABER: This is the hidden story about military food. It has a huge impact on what we eat—the cost to do all the research and develop these techniques is spent in military labs, and then processed food manufacturers can just jump on it and use it to create new products for our tables.

TWILLEY: We went to Natick to try rations, but really, you can eat the products of military R&D anytime you want—you probably did today, already, without even thinking. After all, consumers also want food that’s convenient and portable and doesn’t go bad. In the end, feeding soldiers is just a more extreme version of the same set of challenges. So yeah, what the military eats matters—to us too.


TWILLEY: Thanks this episode to the team at the U.S. Army Natick Soldier Research Development and Engineering Center, particularly David Accetta, who gave up his day to make ours so fascinating.

GRABER: Thanks also to the scientists we met at the food engineering and analysis team: Michelle Richardson, Lauren Oleksyk, Tom Yang, and Mary Shaira.

TWILLEY: Thanks also to Anastacia Marx de Salcedo, the author of Combat Ready Kitchen: How the US Military Shapes the Way You Eat. We have a link to her book on our website.

GRABER: We’ll be back in two weeks with a show that involves one of our favorite substances, and efforts to replace it.


Cutting the Mustard TRANSCRIPT

This is a transcript of the Gastropod episode Cutting the Mustard, first released on February 27, 2018. It is provided as a courtesy and may contain errors.

ROSE EVELETH: So I’m Rose Eveleth. I’m the host of Flash Forward, which is a podcast about the future. But more importantly I am a very huge fan of mustard.

CYNTHIA GRABER: And you and I were actually talking about this, I don’t know, a year or two ago, and you were, like, you have to do an episode on mustard! So why are you obsessed with mustard?

EVELETH: So it’s funny—in thinking about this call we were going to have, I figured you would ask me that question and I realized that I don’t have a great answer. I mean it is objectively the best condiment. But that’s not the best answer. I mean it’s just really delicious, it goes on everything. But I wanted you all to do an episode on it because I am a fan of mustard and I consume a very large quantity of mustard, probably an embarrassing amount of mustard, but I don’t actually know that much about how mustard is made. Like, I’m familiar that there is a mustard plant and a mustard seed. But what actually makes different mustards different is actually sort of a mystery to me. I just eat them. I don’t know that much about them.

NICOLA TWILLEY: That’s what we’re here for, is to do the Googling that you can’t be bothered to do.

EVELETH: Exactly. I’m too lazy, I need an episode of Gastropod.

TWILLEY: Fortunately, Cynthia and I are not lazy at all ever in any way.

GRABER: I hope everyone believes you.

TWILLEY: And so Rose’s wish was our command. I’m Nicola Twilley.

GRABER: And I’m Cynthia Graber, and, as Rose pointed out, this is indeed an episode of Gastropod, the podcast that looks at food through the lens of science and history. We are happy to look into mustard, but Rose, in return you have to answer all my questions about what life might be like in the future. But first, mustard, what do you want to know?

EVELETH: I guess, you know, I eat a lot of mustard and I know a lot about the different kinds of mustard that I could purchase on the market, right? I know the, you know, various varieties of consumer goods related to mustard. I know a lot about how mustard tastes. I know nothing about the pre-going into my mouth parts of mustard. I mean I get the basics—there is a seed. You know, it’s like it’s in many ways like a lot of other things that are made from seeds. The powder seems obvious to me, right? It’s like ground-up seeds. Maybe I’m wrong about that. Who knows? You know, actually.

TWILLEY: Side note, which we didn’t say because we didn’t want to puncture Rose’s belief in all things Gastropod, but we didn’t actually know. Then. Now we do!



GRABER: Rose has been a mustard fan for a long time.

EVELETH: I used to be an athlete in, like, high school. And so I was constantly at various athletic events and they often would sell pretzels and hot dogs and stuff like that. And I think that was when I realized that mustard is far superior to ketchup. And so I was always really into mustard. But I don’t actually know that much about, like, what the process is to take a mustard plant, and if there are, like, multiple different kinds of mustard plants, and that’s how we get these various different kinds of mustard. Like what makes Dijon, Dijon? Is it the plant, is it the seed, is it the processing? Is it some combination of all of those things? And so I was just curious about what where mustard comes from and sort of how all of these different types of mustard are made.

TWILLEY: So many questions! So many answers! But let’s start by getting our basics down: what exactly is this mustard plant of which Rose speaks?

PATRICK EDGER: So the mustard family actually consists of about 3,600 different species and so there’s quite a bit of diversity. Most of the species are the types that you would see growing in the cracks of sidewalks.

GRABER: Patrick Edger is assistant professor of horticulture at Michigan State University.

EDGER: The mustard family really consists of, you know, lots of wild species, but most notably the majority of the vegetable crops that you probably eat and consume every day. You know: broccoli, cauliflower, Brussels sprouts, kale, radishes, as well as like wasabi as a condiment or mustard as a condiment. But in addition there’s a lot of oil-seed types. So we would have things such as, like, rapeseed or canola oil that we would cook with. Those are all from the very same family.

TWILLEY: Fortunately, for the sake of my sanity, the kind of mustard that we can buy in the store labeled as mustard only comes from three plants within this enormous family: black mustard, brown mustard, and white mustard. Confusingly, the white seeds make yellow mustard, and the brown seeds are a kind of beigey-yellow inside, so the whole color terminology is not particularly helpful. But all three kinds of mustard seed have one thing in common: they’re tiny.

GRABER: And this is just the point of another mustard story Rose told us.

EVELETH: Yeah, so my grandparents on my mom’s side are Catholic and when I was a kid my grandma gave me this charm bracelet. And it had all sorts of various Catholic charms on it, it had obviously a little cross but it also had a bunch of other little charms that were relevant to various parts of the Bible or stories or whatever it was. And I was a very, like, tomboy kind of kid so I was, like, I’m not going to wear jewelry, this is stupid. But there was one charm on the bracelet that I was really into because it was this tiny little magnifying glass that you could flip open and you could look into it. And it just magnified one mustard seed. And I guess this comes from a parable of the mustard seed in the Bible.

GRABER: I had never heard of this parable of the mustard seed before—probably because I’m not too familiar with the New Testament.

TWILLEY: Whereas I had, despite never consciously listening in church at school.


EVELETH: Yeah, so I should say that I’m not a scholar of the Bible and nor am I a believer. So, like, I’m not an expert here. But it’s basically about how the mustard plant is really large—they can get to be nine feet tall. And for a plant that big they have small seeds. And so the story, the parable in the Bible, is kind of about that size difference—that when that tiny, tiny seed is planted in the earth it makes a giant plant. It’s kind of one of those “don’t judge a book by its cover,” I think, ideas—that even though the seed is so small it can become this great huge beautiful thing with birds and, you know, branches and all this stuff. So that’s kind of, I think, what the parable is about—if I’m interpreting it correctly, which I could be not doing.

TWILLEY: I am not a believer or a Biblical scholar either, but, from the best I can tell, this mustard seed story is actually more about how the kingdom of God will grow from its tiny beginnings.

GRABER: Which I still don’t really get, but that’s fine. It’s not meant for me.

TWILLEY: But this Jesus connection has an interesting side note attached to it. Supposedly because Christians were so attached to their mustard seeds, they carried them with them and scattered them as they walked, and so mustard plants grew along their trails. One of the places you hear about this happening is in California. People say that one of the early missionaries, Junipero Serra, walked north from the San Diego mission in the 1700s, scattering mustard seeds as he went. And the resulting quote “Bible trail” is apparently still marked by mustard plants today.  People say the same thing about pilgrim routes on the east coast of the U.S. too. You’re supposed to be able to see them clearly from above, thanks to their bright yellow flowers.

GRABER: There’s a Gastropod fan and supporter who happens to—okay—be a friend of yours Nicky, AND he also happens to work for a company that specializes in satellite mapping. So we figured, maybe he’d know if this supposed mustard trail is indeed visible from space. Do the satellite images show the particular visible signature of mustard?

TWILLEY: So my friend Wayne does actually have a real job, so he could not devote too much time to the search, but he told us that unfortunately, most purchasers of satellite imagery actually want something called “leaf-off images”—these are images captured in the winter where there isn’t a ton of foliage covering up all the other features they’re interested in. So, long story short, no luck.

GRABER: If anyone knows whether this California mustard trail tale has been proven true or false, please get in touch!

TWILLEY: But Rose doesn’t love mustard for its religious connections. She loves it because of its heat—its pungency and flavor.

EDGER: That sharp, pungent, bitter flavor that we sense are from compounds called glucosinolates. There are roughly a hundred and twenty-some different compounds and depending on the abundance and the profile of, like, the composition of these various compounds, that’s what gives cruciferous vegetables that sort of flavor.

GRABER: Now remember, these cruciferous vegetables—there are a lot of them: kale and Brussels sprouts and broccoli, just to name a few of my favorites. They have some of these glucosinolates—maybe slightly different ones with slightly different flavors. But things like kale and cabbage don’t have nearly as much pungency as mustard does.

TWILLEY: In other words, there’s a whole spectrum of spiciness between species, depending on which and how much of those 120 different glucosinolates they have.

GRABER: But here’s a question: What purpose does this pungency have for the plant?

EDGER: Yeah, so like most organisms plants do not want to be predated on. They don’t want to be consumed. And being a plant when you’re fixed in a location and you’re constantly combating insects and fungal pathogens and bacteria and viruses, you have to have some way to defend yourself. And so most of the flavors or things that we describe as flavors are actually chemical compounds that plants used to ward off being predated upon. And glucosinolates are one of those examples.

TWILLEY: Unsurprisingly, there’s an evolutionary reason for why the seeds of a mustard plant—the part we use for making the condiment—are much spicier than its leaves, which we use in a salad.

EDGER: If the purpose of a plant is to pass on their genetic material, they will invest quite a bit of that into their seeds to protect actually that next generation. So in mustard seeds, there’s lots of glucosinolates.

GRABER: These glucosinolates are really poisonous to some species—they kill insects.

EDGER: Glucosinolates are actually incredibly toxic even to the plant. The plants will actually sequester a lot of the precursor molecules in vacuoles that safeguard it even from the cell. So that’s how toxic they are.

GRABER: Those special containers get broken open when an insect starts chomping.

TWILLEY: But here’s where these mustard toxins gets even more interesting. A couple of years ago, Patrick published a paper tracing what he calls the great butterfly-mustard arms race. The story starts 90 million years ago, when the first mustard plant ancestors figured out how to stop caterpillars from eating them—by producing some glucosinolates.

EDGER: When the compounds first evolved, it would have been an instant barrier for predation, right? And so that actually would have permitted that ancestral plant that just evolved this novel trait to diversify very rapidly across the landscape. Because now it basically has a wonderful sort of set of armor for any predation to occur.

GRABER: So now the mustard great-great-great-etc. grandparent is super chill. The caterpillar can’t eat it, it’s free to grow and spread across the landscape. For at least a few million years.

TWILLEY: But the caterpillars aren’t done. They are hungry, hungry caterpillars.

EDGER: So the insects evolved a enzyme, a novel enzyme, a brand new gene, that actually, as the insect is consuming these glucosinolates, actually cleaves the compounds—this chemical compound—to make it an inert structure.

GRABER: So now these glucosinolates are no longer toxic to the caterpillars, and now the caterpillars are the happy ones.

EDGER: We then see, as one would predict, it now has a buffet.

GRABER: They can eat as much as they want of this spicy plant that no other insect can snack on.

TWILLEY: And now it’s the caterpillar’s turn to spread and diversify and generally be boss. But, as you would expect, the mustard plant ancestor does not take this lying down. Like Patrick said, it’s an arms race.

EDGER: We actually see repeated cycles of this—minimally, three of them that have occurred over the last 90 million years.

GRABER: This is plant-animal warfare, people. For his experiment, Patrick and his colleagues studied hundreds of species of related plants—plants that trace their ancestry back to those original, millions-of-years-ago genetic splits. This way they could figure out the timeline of when each side temporarily was victorious.

TWILLEY: They could see these big leaps forward in mustard defenses written in the plants’ DNA. One thing to know: lots of plants pass multiple copies of their genomes down to their offspring, instead of the single copies that we humans pass on to our kids. And this extra genetic material gives the mustard plants so many options to play with—so many different pathways to make new, improved glucosinolates.

EDGER: After every set of duplications, you basically would have a new and fancier set of defenses. And this escalated over time until the present day where many of the mustard plants have, you know, over 100 compounds in them.

GRABER: Here’s one of my favorite points in this whole research: this arms race led to amazing success for both insects and plants. As the war went on, it actually created many, many new species of both brassica and butterflies. Both dramatically increased in biodiversity and habitat. It is at least partly due to this arms race that we have kale and collards and cauliflower and Brussels sprouts and horseradish and radishes and mustard and everything.

EDGER: As the brassicaceae were more successful, that actually permitted subsequently the butterflies to be more successful. But then they also each of them have shaped the underlying genomes or even the phenotypes of one another. Ultimately, we really have the butterflies to thank for mustards, right? Mustard compounds. None of this would have existed if it wasn’t for this arms race.

TWILLEY: Next time you squirt mustard on a hot dog, remember to thank a caterpillar. So that’s cool, but my favorite part of Patrick’s experiment is that as part of his whole process, he found plants that are living today that have the level of glucosinolates that mustard used to have in the past.

EDGER: There are actually relatives from those ancestral intermediates that you can go out and you could potentially sample. And that was part of the study. We found all these sort of intermediate lineages—remnants. And from that, we can actually make estimates of what those profiles probably were like. We can’t be very definitive about it but we can make really pretty solid estimates of what those ancestral states would have been like, going back to at least 90 million years.

TWILLEY: I temporarily lost my mind for a minute when I heard this and decided that what Cynthia and I needed to do was track down all these milder-tasting relatives and do a mustard tasting through evolution, from bland to fiery.

GRABER: That sounds awesome, of course, but then you realized that it’s just the two of us and we have to put out shows and that would take months of plant collection and seed crushing.

TWILLEY: But if some millionaire mustard-ophile out there would like to fund this quest, I am available to talk offline. The 90-million year mustard tasting awaits!

GRABER: And I will happily join in. So Patrick and his colleagues wrote about this butterfly-mustard arms race. But here’s something that might scare you: the battle is not yet over!

EDGER: We see this constantly happening. So a lot of cabbage butterflies, if you grow any cruciferous vegetables in your backyard—broccoli or cabbages or cauliflower or what have it—you’ll see lots of cabbage butterflies always trying to predate on it.

TWILLEY: And that means that the plants need to be upping their game. And they will.

EDGER: I could imagine a mustard being spicier.

TWILLEY: Not just spicier, but even with a slightly different flavor profile, from new variations and combinations of these glucosinolates. Basically, we can’t even imagine the mustards of the future!

GRABER: Rose, this is the episode you get to make!

TWILLEY: Right, you do mustards of the future, we do the mustard science, and, next, mustard history.


HAYLEY SAUL: At this stage, I would say that these findings are the earliest conclusive use of spice for a culinary purpose.

GRABER: Hayley Saul is an archaeologist at Western Sydney University. And, a few years ago, she and her colleagues discovered the earliest known example of spiced food in human history—dishes perked up with, yes, mustard.

TWILLEY: OK, picture the scene. It’s more than 6,000 years ago, and you are in northern Europe, eating a plant called garlic mustard.

SAUL: So there were three main sites where we found the evidence of garlic mustard. One of them in Germany, which is a site called Neustadt, which is actually now underwater. It’s been excavated underwater. That inundation is actually one of the reasons why the pottery and the pottery residues are very well preserved because the waterlogging is great for preservation. And the sites in Denmark—so the sites are called Åkonge and Stenø,and they’re located on the edge of a bog.

GRABER: There are a lot of sites like these found near water, because water is a great source of food. But the people who were living at these sites, were they just hunting and gathering all the wild plants and animals that lived in and near the water? Who were these people?

SAUL: So, you know, all of the sites actually span the sort of Mesolithic/Neolithic transition, which is the time at which people were starting to just domesticate and experiment with domesticated plants and animals. So the people that lived kind of in the Mesolithic tend to be associated with hunting and gathering. But it’s actually much more complicated than that, really. It wasn’t the case that people just gave up on hunted and gathered foods and then adopted these new, more superior types of domesticated foods. They were actually combining things and it was just a period—I like to think of it as a period that was very creative. And there were new types of food coming in but people were starting to sort of explore how they can combine it with food that they’d used for years.

TWILLEY: What Hayley’s saying is surprising to me. I don’t tend to think of Mesolithic or Neolithic people as being culinary wizards or experimenting with their food to create new textures and flavors.

SAUL: I think there’s been a kind of an assumption in general that in prehistory, people were driven by just the need to get a certain amount of energy and that there was nothing particularly artistic about food practices in prehistory. And in part that’s brought about just because of the techniques that we have and the difficulty of finding certain evidence. So it’s quite easy to document animal bones on a site and slightly more difficult to document plants because they don’t preserve very well.

GRABER: In the past, scientists have been able to figure out what people were eating on a kind of more general scale—did they get more of their calories from protein or from fat, did they go fishing, or were they butchering domesticated cattle? But, until recently, it’s been much more difficult to get a fine-grained look at the flavors of the foods prehistoric peoples were cooking. But now, there are new techniques that Haley says can give a higher resolution look at ancient diets.

TWILLEY: These higher resolution techniques include starch analysis, as well as drilling into food residue to analyze the fats. There’s also a kind of microscopic analysis to match the tiny fossil remnants of plant cells, which are called phytoliths, to a catalog of different plant species collected from the area. The combination of all these techniques, plus how well preserved the food residues were at these sites, meant that Hayley and her colleagues were able to get that more nuanced and detailed picture of what these early northern Europeans were eating.

GRABER: And there was a lot of food residue for Hayley and her colleagues to analyze.

SAUL: In some cases it was up to a centimeter thick, because the pottery wasn’t necessarily cleaned. So it was just becoming more and more carbonized, and thicker and thicker residues. A bit like you would use a skillet, the flavor is partly brought to the food because the skillet is sort of reused again and again and again. And it’s only when the carbonization of that residue becomes so distasteful that the pottery is actually thrown away into the lake or into the sea. And at that point, it’s just like a record of reuse and a kind of build-up of all of these different meals that the pots been used for.

GRABER: And Haley’s big find from this food residue? These Mesolithic people were revving up their stews with a plant called garlic mustard. I know I said this already, but—drumroll!—this is the earliest known culinary use of a spice in the world.

SAUL: It’s from the seed husk, the actual sort of hardened shell of the seed, which has a flavor, if you grind it up, much like mustard.

TWILLEY: Hayley was able to figure this out by comparing the phytoliths—these plant micro-fossils—to the microscopic structures you find in garlic mustard today.

SAUL: I had to do a lot of just going out into the countryside and foraging for plants that were edible and, you know, making up the reference collections and things. And it’s one of those plants that you could so easily overlook. It’s just everywhere. And once you get your eye in you can see that it’s everywhere. It’s a plant that’s available across the whole of Europe, right into India and parts of Asia as well. But it’s not just usable for the seeds. The leaves of the plants are edible as well. The reason it’s called garlic mustard is because the leaves have a very garlicky aroma but the seeds have a very mustardy flavour. So you can sort of combine two different flavors in one plant really.

GRABER: That sounds delicious. But we were wondering—maybe garlic mustard was a major source of calories for the folks in these settlements. How can we know it was being used intentionally to flavor their food?

SAUL: The seed itself of Alliaria petiolata is very small and it’s woody. Some people have suggested that it has properties for preservation. It may have medicinal properties. But, because it’s so woody, in terms of delivering anything like energy or a great deal of vitamin nutritional value, it doesn’t really do that. So it seems to be much more that it’s being used at least in part because of its aromatic properties. So it is imparting flavors into the food.

TWILLEY: Basically, it turns out that Hayley is pretty confident that Mesolithic people had Rose Eveleth-style levels of enthusiasm for mustard. They too thought that there was nothing that didn’t taste better with some mustard!

SAUL: So we were finding from the lipid residue analysis that they were combining garlic mustard with marine fish.

GRABER: They also made stews of garlic mustard and meat from animals they either hunted or raised, like cattle or deer.

SAUL: It’s such a common spice it’s almost like they’re using it as we would use salt and pepper. And that suggests to me that it could have an even longer history. But we just don’t know at this stage.

GRABER: And actually, there are even older sites around the Mediterranean that have plant remains from other spices and herbs—poppy, cumin, and coriander—but the plant bits are not embedded in cookware. So we can’t be positive that people were actually eating these spices. But maybe they were.

TWILLEY: Really, though, the important question here is, what did these mustard-spiced dishes taste like? Fortunately, Hayley can answer that one too.

SAUL: Because my research involves me sort of going out and foraging for plants for my reference collection, the temptation is always there to try out what the flavors of those different plants were, yeah, so I have made some unusual concoctions of my own. But if you can find some garlic mustard, just grinding it up in a pestle and mortar and you can smell the mustardy flavor as you’re grinding it as well. And it’s delicious in a nice stew.

TWILLEY: Yes, that’s right: Hayley made her own Mesolithic garlic mustard stew.

SAUL: I used it with some venison. My dad’s a butcher, so I managed to get a nice cut of venison.


SAUL: It did taste quite contemporary. It’s not such a strong flavor as the sort of mustard that you would get in a pot. But there is definitely a sort of flavor of mustard.

GRABER: I love the idea that the earliest known use of spice involves garlic mustard. Two delicious flavors in one plant. But, for Hayley, even more importantly, this finding helps us rewrite the stories we tell about the people who were alive back then.

SAUL: It’s easy to fall back on the idea that people were sort of caveman-like and, you know, they were just out to sort of eat as much and as often as they could because they never knew when their next meal was, and things. But actually I would say that they were extremely sophisticated, and they had such sophisticated skills at acquiring food that they could sort of be really creative about the ways that they were combining foods.

TWILLEY: This is another thing that Rose and our Mesolithic friends have in common: mad mustard-pairing skills.

EVELETH: I put it on everything. I mean, I’m a big carb person. So, like, any kind of bread product, it’s good on. Olive bread with mustard is extremely delicious. I mean, obviously there are pretzels, but you can also put mustard powder on things like popcorn. So, like, a little bit of soy sauce and mustard powder on popcorn is delicious.

GRABER: I’d love to try that popcorn. But so I was wondering, you know, can you walk us over to your fridge? Tell us about how many jars you have and could you list some of the ones that you see?

EVELETH: Yeah. All right, I will—I’ll take you over. Hopefully my dog doesn’t get too interested in what we’re about to do. Okay, I’m opening the fridge. Let’s see, where are we. So there’s this great mustard place called—I’m going to mispronounce it. Maille? Maille? M A I L L E. Okay, so we have a bunch of those. I have a walnut mustard from them. I have a Dijon blackcurrant liqueur mustard from them, which is really good. It’s like—it tastes like Thanksgiving. It’s amazing. Really good on French fries actually, because, like, they’re sort of a good vehicle for any kind of mustard but they taste like Thanksgiving French fries. I have a blue cheese mustard which is super strong. You kind of have to, like, be a little gentle with this one. We also have an amber ale honey mustard from this farm up in Vermont that is near a place where we go skiing every year. We, of course, have sort of the standard spicy brown for sort of hotdogs and all that stuff.

TWILLEY: There’s more—many more jars. The thing is, it’s not just Rose that’s crazy about mustard. Her partner Robert is too. It’s actually central to their whole relationship, at least in terms of condiments.

EVELETH: We have a running joke, because I subscribe to the Mustard Museum’s newsletter, and it’s sort of full of mustard information. And a couple of years ago, they sent one out and that was, like, you know, we do weddings. And I don’t know if they were serious or not but we have a running joke about getting married at the Mustard Museum.

GRABER: Nicky, you and I did not have wedding plans.

TWILLEY: Because we’re already work married.

GRABER: But we did actually visit the Mustard Museum. It’s just outside Madison, Wisconsin, and we happened to be in town to do a Gastropod live show. When in Madison, go see mustard, apparently.

BARRY LEVENSON: So anyway we’re going down into the museum: the world’s largest collection of mustard, mustard memorabilia, and fine mustard art.

TWILLEY: Barry Levenson is the founder and curator of the National Mustard Museum. He’s a lawyer with a serious mustard obsession.

LEVENSON: We’ve got nearly 6,000 different mustards here. So, in addition to American yellow mustard, classic French mustard, you have horseradish mustard, you have whole grain mustards. We have hot pepper mustards. We have herb mustards, we have fruit and vegetable mustards. We have garlic mustard. We also have spirit mustards, which would be mustards made with beer, with wine. We have exotic mustards. The exotic mustard category can be anything from curry mustards to truffle mustards to mustards with ginger. Right now, we’re standing in front of some of the French mustards.

TWILLEY: But before things get even more insane—although personally I think getting married at the mustard museum is already pretty insane, and having 6,000 jars of any condiment is definitely a warning sign—we need to back up. How did we get from garlic mustard seed stew to the condiment-filled jars we know and some of us love today?

GRABER: Before we clear your sinuses with some strong Dijon, we have a sponsor to tell you about.


GRABER: To get to France, first we have to go back to ancient Egypt.

LEVENSON: We also know that the ancient Egyptians would chew mustard seeds along with their meats and that would flavor it. But they would just take the seeds, because mustard seeds themselves are inert.

TWILLEY: There’s actually a chemical trick to mustard. So: the glucosinolates in mustard seeds—they’re slightly different compounds in black vs. yellow vs. brown mustard seeds but they work the same way. Which is that they they react with a particular plant enzyme in the presence of cold water to produce that fiery essential oil of mustard. This multi-step trigger process is another way that the plant holds fire until the caterpillar actually crunches into it and sets off that reaction.

LEVENSON: It’s only when combined with some liquid do they release their heat and their pungency. As a result, that’s what the Egyptians would do. They’d say, okay, have some meat and chew on some mustard seeds.

GRABER: Then the Romans decided to turn mustard into a sauce.

LEVENSON: We know that the Romans were using mustard seeds in some of their sauces and then that migrated into the Roman Empire, specifically into the area now known as Dijon, where the monks were making pretty much what we know as mustard today back in the 12th and 13th centuries.

TWILLEY: The first reference to mustard in the Dijon archives occurs in 1336—it’s a record of a whole cask of mustard being consumed at a banquet. So mustard was already a big deal. The first ordinance specifying how to make Dijon came at the end of that century. Basically, soak the seeds, crush the seeds, and then add vinegar to the paste. To go back to our chemistry for a minute, using an acidic liquid like vinegar puts a brake on the reaction, which gives the resulting mustard a long-lasting, slow burn—as opposed to the quick, pungent hit of mixing it with water.

GRABER: Dijon mustard got super popular in 1756. That’s when a major mustard maker in Dijon changed his recipe from vinegar to verjus—it’s a juice made from unripe grapes, and it’s not quite as acidic as vinegar. Today, if you buy Dijon mustard, it doesn’t usually have verjus, but the makers still try to make it taste like the recipe that made it famous. They’ll often use a combination of white wine and vinegar.

TWILLEY: Technically, Dijon is supposed to only be made with either black mustard or brown mustard seeds. But basically nobody uses black mustard commercially because the seed heads are so fragile that you have to harvest it by hand.

GRABER: Seventy to eighty percent of the mustard seed exported to make condiments comes from industrial fields in Canada, which happens to be the world’s mustard basket. And Barry says a lot of those mustard seeds go to France.

LEVENSON: France, of course, is known for mustard. The per capita consumption of mustard in France is greater than any other country.

TWILLEY: Since the 1800s, Dijon has been found at tables throughout France. In my home country, though, we developed a rival: Tewkesbury mustard, which is mustard mixed with its close cousin, horseradish, for a little extra something something. This mustard was sold and transported dry in balls, known as Tewkesbury fire balls. They were a staple in English kitchens in the 1600s.

LEVENSON: Shakespeare loved mustard and wrote about mustard in several of his plays.

GRABER: Shakespeare even used this famous Tewkesbury mustard in one his slightly less famous plays, King Henry IV Part 2. He wrote, “His wit’s as thick as Tewkesbury mustard.”

TWILLEY: This is not a compliment.

GRABER: Barry has his own favorite Shakespearean mustard quote.

Barry: “What say you to a piece of beef and mustard? Aye, a dish I do love to feed upon,” from Taming of the Shrew.

TWILLEY: Here’s the Shakespeare mustard reference I found surprising though: eye of newt, which is one of the things the witches stir into their cauldron in Macbeth—”eye of newt and and toe of frog, wool of bat and tongue of dog,” etcetera, etcetera. So eye of newt—I always thought that was the eye of a newt. But it isn’t! It’s an old name for a mustard seed.

GRABER: Rose, the rabbit holes you’ve sent us down! But Shakespeare’s Tewkesbury isn’t the most famous British mustard today.

LEVENSON: That would be Colman’s. The classic hot, just good, strong mustard that just kind of goes right up in the nose.

TWILLEY: Colman’s in the yellow tin—it’s *the* British mustard.

LEVENSON: Yeah, Colman’s dry is kind of the gold standard.

TWILLEY: The thing about Colman’s is, as Barry points out, it was originally a dry mustard—and you can still buy it that way today. I have two tins of Colman’s mustard powder in my kitchen as we speak. But grinding and selling dry mustard as a powder—that actually wasn’t Jeremiah Colman’s idea.

GRABER: The inventor of powdered, dry mustard is lost to history. The only record comes from an article published in 1807, in the Gentleman’s Magazine. And the author wrote that, in 1720, quote, “it occurred to an old woman of the name of Clements, resident at Durham, to grind the seed in a mill and to pass the meal through the various processes which are resorted to to make flour from wheat.”

TWILLEY: Ms. Clements’ mustard flour was a huge hit. Even George the First gave it the thumbs up. But she kept the secret to herself for many years. Jeremiah Colman was originally a flour miller, with a mill of his own. He didn’t turn to mustard until nearly 100 years after Ms Clements’ big breakthrough. But then he conquered the British mustard market, with a special blend of locally grown white and brown mustard seeds ground to a fine powder.

LEVENSON: Colman’s mustard was just dry mustard for the first 60 or 70 years before someone decided at Colman’s, well, why don’t we actually make the mustard condiment?

GRABER: So while Dijon is made from brown mustard seed, Colman’s is a blend of white mustard and brown mustard seeds. Brown seeds, like the ones used in Dijon mustard, they give you more of a horseradish-y, sinus hit.

LEVENSON: It gives you more of that nose hit as opposed to the yellow seed, which is more pungent just on the tongue.

TWILLEY: So France has its favorite mustard, Dijon, England has Colman’s, but in America, it’s all about French’s. So what’s that?

LEVENSON: That came about a little over 100 years ago, when Mr. French decided that even though there were European mustards, they weren’t all that popular. What this country needed was a brightly colored, happy mustard and that’s what French’s mustard has been.

GRABER:  Actually French’s mustard—it first came out at the turn of the last century—it was originally called “French’s Cream Salad Brand.” Not only was it bright yellow because Mr. R. T. French added turmeric to the recipe, but it was also creamier and sweeter. And it was a huge, huge hit almost instantly in America.

LEVENSON: It is generally made with the yellow seed, so it is going to have a very different kind of flavor profile. And that’s the kind of thing that when you go to the ballpark, I think you’ve got to have yellow mustard at least on that first dog. Because you hold up the hotdog, you know, and you see the blue sky, the green grass, the brown base paths and there’s just something about that yellow squiggle of mustard that makes life so worth living that day.

GRABER: Oh Barry.

TWILLEY: People have strong feelings about mustard.

MADHUR JAFFREY: It’s very important and it’s an ancient seed that we’ve had forever.

GRABER: Madhur Jaffrey is an actress and food writer. She’s probably the most famous writer of Indian cookbooks—she’s the person whose cookbooks helped popularize Indian cooking at home in the West.

TWILLEY: We’ve been stuck in Europe and America so far this episode, but mustard is global. And India has its own serious, long-term mustard thing going on. It’s not a condiment-based relationship, but it’s central to Indian cuisine

JAFFREY: It’s been amongst our two hot spices that originated in India. We started out thousands of years ago with mustard seed and black pepper. Those are native to the region and those were the only spices we had that were hot, and chiles of course came much later. So for many centuries, they were even more important than they are today, but they’re still very important today, because one of the oils that we cook with, which is very important, is mustard oil.

GRABER: Mustard seed and, even more importantly, mustard oil is found in kitchens throughout the Indian subcontinent.

JAFFREY: It’s used for cooking a lot of food in several states. Bengal cooks a lot with mustard oil. Kashmir cooks a lot with mustard oil. So these are two states where it’s almost the state oil. And there are certain dishes that would be cooked always with mustard oil. If you’re steaming a fish, you will definitely use some mustard oil. In Bengal, if you are making this muri, which is puffed rice, you’ve puffed it and then you want to dress it quickly with different things, you’ll put, among other things, mustard oil on it and have it for breakfast.

TWILLEY: So but here’s what’s weird. Mustard oil is banned in the U.S. as a food. It has been since the 1990s.

JAFFREY: When I buy mustard seed oil, it says on top: “Use for external purposes only.” People in India eat it and survive and nothing happens to them and they live long lives. We put it on babies, we—you know — but externally we put it on babies. But I keep reading it and ignoring it. It’s just like what they used to say with coconut oil. “Don’t cook with coconut oil.” And people go through fashions and suddenly now everybody is cooking with coconut oil as if it’s the best thing in the world.

GRABER: You might think that maybe the U.S. government was afraid of those pungent, insect-fighting glucosinolates. But no. The FDA thinks the problem comes from a fatty acid that’s found in the seed. Apparently tests on rats show that in high doses this particular fatty acid can cause heart lesions. But frankly, as Madhur says, literally billions of people have been cooking with mustard seed oil for thousands of years.

JAFFREY: I wouldn’t give it up. No. It is in a lot of things that I cook. I cook everything from all over India and I use it all the time.

TWILLEY: For Madhur, the magic of mustard is in the way you can manipulate its heat.

JAFFREY: It’s like a Jekyll and Hyde of both spices and oils. If you use it plain, it’s quite pungent. So when we want that pungent flavor, we use it plain. But if you heat the oil or if you pop the mustard seeds, they turn sweet and nutty. So it depends on what we want. It can change its shape, as it were.

GRABER: So in India, cooks know that cooking heat tames the fieriness of mustard seeds and oil. But Barry says condiment markers can use other tools to manipulate that heat, too.

LEVENSON: Which seed you use, how much water, how much vinegar is going to be used. There are all kinds of ways that mustard makers are able to change the heat of the final product.

TWILLEY: In fact, mustard is surprisingly nuanced. You think of it as this blast of heat on a sandwich, but, depending on how you make it or how you pair it with food, mustard doesn’t have to steal the show—it can fade into the background and just make everything else taste better.

GRABER: I never really had strong feelings about mustard one way or the other, unlike all of our guests this episode, but the bagel shop near me uses mustard butter on their bagel-egg sandwich and it’s mind-blowing. So I also started using a layer of mustard in my savory galettes—these are free-form pies—and it totally ups the game.

TWILLEY: Whole-grain mustard smeared inside the pastry shell of a quiche, before you add the filling: unreal. And mustard powder is my secret ingredient in cheese straws. But Barry and Rose have taken this pairing game a little further.

LEVENSON: It’s something that you can also use in brownies because it accentuates the flavor of chocolate.

EVELETH: This is going to sound disgusting to a lot of people but I think it’s delicious: a little bit of mustard on Oreos is extremely good.

GRABER: Wow, that is an unusual one.

TWILLEY: Wait, wait, wait so are we talking like French’s here or what are you doing? Like, how is that?

EVELETH: Like you sort of dip a double-stuffed Oreo into like, a little bit of mustard, in Dijon mustard.

GRABER: And what does that do for the Oreo?

EVELETH: Well, because the Oreos are so sweet, right? Like, you’ve got the chocolate cookie and then you’ve got that, like, really saccharin middle chemical bit—like, I don’t know what it is—

GRABER: The white part.

EVELETH: The white part—it’s so sweet that just a little bit of like spiciness or that little bit of, like, mustard flavor is really a good foil to the Oreo. It’s delicious. I know everyone listening is going to be, like, you’re a psychopath. But I love it.

GRABER: I totally want to try this.

EVELETH: It’s really good.

TWILLEY: I might skip mustard Oreos. But I’m much more into Rose’s most recent mustard revelation.

EVELETH: I have been really into making Bloody Marys recently, and I put a little bit of mustard in my Bloody Mary mix.

TWILLEY: Wait, the spread or the powder?

EVELETH: So I’ve been experimenting with both. So I will put a little bit of powder in the ring, like, the ring that you put on the glass.

TWILLEY: Oh yes, that does sound really good.

EVELETH: And then a tiny bit of it in. Yeah, it’s super good. You have to be careful because you could definitely overdo it with mustard powder particular. But I also put a little bit of Dijon in the actual sort of concoction, the tomato paste concoction that I used to make Bloody Marys. I’ll make you Bloody Marys any time, they’re my favorite drink and I’m really into making them.

GRABER: I’m so there!

TWILLEY: And that’s it for today’s episode because we have somewhere to be! There is a mustard Bloody Mary calling my name.


GRABER: Thanks this episode to Rose Eveleth. She is the host of a fascinating podcast called Flash Forward—it’s all about possible and not so possible futures. She had a recent one on a future where we’re all telepathic, and another scary and possible one about what happens if the census goes haywire.

TWILLEY: Thanks also to Patrick Edger of Michigan State University, Hayley Saul of Western Sydney University, and Madhur Jaffrey, legendary food writer and actress. We have links to their work on our website, gastropod.com. And, finally, thanks to Barry Levenson of the National Mustard Museum in Middleton, Wisconsin.

GRABER: We’ve got some more fascinating mustard stories involving mustard gas, mustard plasters, and mustard sounds saved for our special sustaining supporters newsletter: if you’re able to donate $9 a month on our website or $5 per episode on Patreon, you too could enjoy some more mustardy goodness!


GRABER: We’re back in two weeks with a few famous friends. Yep, we’re hanging with Nigella and Yotam and we’re name-dropping like we just don’t care!

Secrets of Sourdough: TRANSCRIPT

This is a transcript of the Gastropod episode Secrets of Sourdough, first released on December 19, 2017. It is provided as a courtesy and may contain errors.

CYNTHIA GRABER: That’s really good.

NICOLA TWILLEY: Really good. That’s good.

GRABER: One more—I know, I just need one more little bit.

TWILLEY: Just one more piece.

GRABER: I’ll join you in that.

TWILLEY: How can I not? It’s so good.

GRABER: It’s so warm and yummy. I’m going to taste some of this. Mmmm, Nicky—hot pita with garlic butter?

TWILLEY: Welcome to an episode of carb lovers anonymous!

GRABER: Not so anonymous. Nicky, they know who we are. I’m Cynthia Graber—

TWILLEY: And I’m Nicola Twilley, and this is actually Gastropod, the podcast that looks at food through the lens of science and history. And Cynthia and I are the not-so-anonymous carb lovers.

GRABER: We spent three days in Belgium with two scientists and more than a dozen bakers. We were in theory investigating a deep scientific question about bread—but actually

TWILLEY: We were eating our body weight in bread. And Belgian waffles.

GRABER: Nicky, I still am not sure I can forgive you for encouraging me to eat that second hot Liege waffle—I felt a little sick afterwards—but it was frigging amazing.

TWILLEY: Listeners, I ask you: was that a bad thing that I did? No. When in Belgium, eat the Liege waffles.

GRABER: But you’re not here to find out how many pieces and what types of bread we gorged ourselves on in a 72-hour period. You want to know what we wanted to know: all about sourdough. In fact, many of you have written us emails asking us to do this very episode. For instance, listener Alex Freedman, who lives nearby in Somerville but grew up in San Francisco, wanted to know about the history of sourdough. Alex, we’re on it.

TWILLEY: Listener Danae Garriga is northern Illinois requested an episode devoted to sourdough starters. As a baker, she’d read about wild yeasts and how the environment the starter is made in affects the microbes in it. And she wanted to know, if she gave some of her sourdough starter to a friend, would the microbes in that starter change? Danae: exciting news, that is exactly what we went to Belgium to figure out, in the world’s most delicious science experiment. In fact, we have the world exclusive scoop on this brand new research!

GRABER: It’s true, we tagged along with scientists at the cutting edge of sourdough. The question they were trying to answer is: those microbes that make up your wild sourdough starter, where do they come from?

TWILLEY: Is it from the water, like so many people—especially in San Francisco—believe? Is it from the baker or the bakery?

GRABER: Or is it from the flour?

TWILLEY: This was a gigantic scientific mystery. Up till now.

GRABER: We are going to take you along to Belgium with us on this path of scientific sourdough discovery. But a quick note, if you’re a regular listener, you know we have a Gastropod drinking game: we say microbes, you yell, “drink!” and then, you know, do so. If you do that this episode, you’ll be drunk. Really fast.



GRABER: This summer, Nicky and I traveled to a remote corner of Belgium. We were visiting the headquarters of Puratos, one of the world’s biggest bakery ingredients companies. They’d invited more than a dozen bakers from more than a dozen different countries to participate in a science experiment.

PAUL BARKER: Hi, my name’s Paul Barker and I’m from the U.K.

CHRISTOPH VÖCKING: My name is Christoph Vöcking, I’m from Germany.

JOSEY BAKER: My name is Josey Baker, and I’m from America.

STAVROS EVANGELOU: Hello, my name is Stavros, I speak English not good.

HAKAN DOGAN: I am Hakan, I’m from Turkey.

LETICIA VILCHIS: I am from Mexico. I am a baker too.

TWILLEY: And then there were also two scientists: Anne Madden and Rob Dunn. They work together in Rob’s lab at North Carolina State University. And they were meeting all these bakers for the first time too—to introduce the experiment.

ROB DUNN: We know that when you make a sourdough, the species and strains of microbes in that starter, they influence the nutrition of that bread, they influence the flavor of that bread. They influence every part of the bread. And yet it’s still pretty mysterious what determines which of those microbes are originally in your starter.

GRABER: Rob and Ann are microbiologists. They’ve been studying communities of microbes in all sorts of places—your bellybutton, your showerhead…

DUNN: And we’ve worked on microbes for a long time and often the responses is repulsion, like oh gross, there are microbes in my house.

ANNE MADDEN: When you talk to people about bacteria that might be in their bathroom it’s ugh, ugh, please stop talking, please don’t tell me any more. I don’t want to know. But when you talk to people about the microorganisms in their sourdough, it’s like, what did my children do? This is lovely. Like, can we put it on the refrigerator? Are there pictures? I love the response.

DUNN: And this was this one little niche where people seemed to gather around the idea that this was a beautiful kind of microbe, that there was something wondrous about them.

TWILLEY: And there really is something wondrous about a sourdough starter. It’s a community of wild microbes that somehow, miraculously, makes bread rise.

GRABER: And you need something to make the bread rise, because otherwise, if you mix flour and water and bake it together, you get matzah. Or, you know, a cracker. Hard and flat.

TWILLEY: Today, if I’m a baker and I want to make my bread rise, I can just go to the store and buy some baker’s yeast. Baker’s yeast is precisely one microbe, Saccharomyces cerevisiae, but it does the trick.

GRABER: But bakers have been making leavened bread in an oven—bread that puffed up and got soft like ours does today—people have been baking that for thousands of years. The ancient Egyptians made bread.

KARL DE SMEDT: So our question was okay, so where did the Egyptians bought their yeast? Because to make bread you need flour, water, salt, yeast. So where did they bought their yeast? They didn’t. It was there.

TWILLEY: This is Karl de Smedt. He’s the communications and training manager at Puratos, and, for this experiment, he was the one in charge of wrangling the bakers. And before we got started on the science, he dropped some sourdough history on the group.

GRABER: Nobody knows exactly where and when sourdough bread was first invented. The earliest evidence we have for making bread comes from a site in Africa. Archaeologists have dated the remains of that bread to about a hundred thousand years ago. It was probably made from pounded sorghum and water and baked on a hot stone.

TWILLEY: We’re not sure whether that was a sourdough or not—but it may have been something like the injera that Ethiopians still eat today. That’s sort of spongy and bubbly, and those bubbles are created by a community of wild microbes, just like today’s sourdough.

GRABER: Basically, if you combine ground up grains—something like wheat—with water, and you forget about it and leave it alone, eventually it starts bubbling. And that’s because a bunch of different microbes, usually a combination of fungi like yeast and bacteria like Lactobacillus, they colonize the mixture and feed on the flour and that is both the start of beer, and a sourdough starter!

TWILLEY: There’s hot debate among historians about whether humans first figured this out because they were making booze, or making bread. I am on team beer, to be honest, but short of Cynthia finally inventing her time machine, we will probably never know. Either way, humans figured that this wild bubbly mix made their flatbreads into breads—the non-flat kind. These loaves of bread would all have been sourdoughs. There was no other way to make bread rise.

DE SMEDT: So for thousands of years sourdough was being used by each and every baker or person that would bake bread.

GRABER: And even before people knew what microbes were, they were already caring for these wild communities of bubbling beige gloop, feeding them with more flour and water to keep them alive and happy. They figured out that you only need to add a dollop of starter to your dough to leaven it, which means you can keep the same starter going for years and years—decades even—just by feeding it with flour and water and using a little bit of it every time you bake. It becomes like your own personalized wild leavening mix that you can keep alive and use it again and again and again.

TWILLEY: Other people developed variations on this approach. In ancient Greece, for example, Pliny the Elder describes people saving a piece of their dough from the previous day to raise their bread the next day.

GRABER: Pliny also reported that people in Gaul and Iberia, otherwise known as France and Spain, they would use the foam they’d skimmed from beer to produce what he called “a lighter kind of bread than other peoples.” It’s the beer/bread question again—either way, it’s communities of microbes that grow on mashed-up grain-and-water mixes, and that have the power to both leaven bread and ferment sugar into alcohol.

TWILLEY: Over time, we figured out how to curate and stabilize these communities, so that they worked as expected, most of the time. Still, they were all a little different and a little finicky—my sour culture might make bread rise faster, yours might produce a better crumb, mine might all the sudden stop working.

GRABER: But these sour cultures were the only tool we had to bake leavened bread. And then everything changed.

DE SMEDT: And with the discovery of the microscope, with some research done by scientists, actually with Louis Pasteur, who wrote this Memoire sur la Fermentation Alcoolique, who opened actually the production of commercial baker’s yeast.

TWILLEY: It was two Hungarian born brothers, Charles and Max Fleischman, who first commercialized Pasteur’s insight. They started selling baker’s yeast—fresh yeast, sold in little cakes.

DE SMEDT: And it was such a convenient product that bakers embraced it with open arms. They all started to switch from that very inconsistent, complicated, long process that is sourdough towards something that is very precise, very accurate, very fast, very reliable, that’s called yeast. And so, in 150 years, bakers switched completely.

TWILLEY: Like I said, commercial baker’s yeast is just one microbe, not a community. Which has both pros and cons.

DUNN: So, commercial yeast is super boring, right. So nobody ever thought Saccharomyces cerevisiae, this baker’s yeast, was the most flavorful, that it had the best effect on the bread. We just thought you could make a ton of bread really quickly.

GRABER: Because not only is it a single yeast that you can buy whenever you need some, and that doesn’t need feeding or watering or loving care, but it also makes your dough rise a lot faster than that sourdough starter you’ve been keeping alive. By the 1960s, boring commercial baker’s yeast was available as shelf-stable granules in little packets. And, by then, bakers had also invented industrial processes that sped up the whole rising and baking process to just over three hours.

TWILLEY: This  bread—the bread of 1960s, the bread of our parents—this was not good bread. Karl says the 1960s was bread’s nadir. Sourdough all but disappeared.

GRABER: The 1960s sucked for bread, commercially. But it was also the time of good bread’s rebirth. The country’s first Zen Buddhist monastery was created in California in the late 60s. It was called Tassajara. The monks there baked bread slowly as part of their spirituality. They saw bread as being alive.

TWILLEY: And a young Zen student named Edward Espe Brown, who lived and worked at Tassajara—he published a book collecting the monks’ recipes in 1970. It was super homemade and hippie—the cover is made of brown paper, it was published in a tiny edition by Shambhala Press, and Edward received the princely sum of $100. But it sold out immediately, and went into second and third and fourth printings. Making your own sourdough bread at home became part of the counterculture—and a way to eat healthier.

GRABER: At the same time, there was another group of people who thought that commercial bread kind of tasted like crap. They weren’t inspired by spirituality or health, but by flavor. Between them, these two groups helped create the sourdough revolution.

TWILLEY: This revolution took a while to spread. During Karl’s own training as a baker, he never set eyes on a sourdough. It wasn’t till he started working at Puratos, in 1994, that he first encountered it.

DE SMEDT: I’d been to one of the better bakery schools in Belgium and we never learned how to make sourdough. It’s just not part of the educational program. So it was a discovery. I had to take out a bucket of the fridge. It looked strange. It smelled strange. It was funny when you touched it—it was a bit sticky.

GRABER: But Karl is thrilled to say things have been changing for sourdough.

DE SMEDT: And we see now, the latest 20—25 years there is a revival of sourdough and we think we are at the beginning of something very nice that will come in the coming years where sourdough will again take its place in the bakeries that it deserves.

TWILLEY: With that sourdough revival came a renewed appreciation for the diversity of microbes in sourdough starters—and they are diverse. As we discovered.

DE SMEDT: Come closer, come closer, because something very special is going to happen. You have to realize that what we have here is probably the most unique place in the bakery world.

GRABER: Karl led the group up the stairs and to a closed door.

DE SMEDT: Ready? Keep your eyes on the door, let’s go for some magic. Three, two, one…

BAKERS: Whoa! Ahhhh!

TWILLEY: And with that, we stepped inside the world’s one and only sourdough starter library.

GRABER: It’s a library, yes, but instead of bookshelves, there are 12 illuminated refrigerators with glass doors so you can see the jars inside. Karl’s collected 93 different sourdough starters from 17 different countries. And they look totally different from one another.

DE SMEDT: Some are liquid and some are stiff. And then some are very dark. Some are speckled. Some are almost looking like crumble, because they’re so dry. So there’s a lot of colors—dark to brownish to yellow, and then the normal white ones.

TWILLEY: Karl took some of the jars out and allowed us to smell the starters. Some smelled fruity, some were acidic, some were biscuity, some were creamy.

DE SMEDT: The Chinese, for example, one of them is very meaty. When I open the jar, it’s like almost a sausage, very savory. Some are really very pungent, when I open the jar and smell, you really feel the acids go into your nose, and it’s like if you were to have a spoon of very heavy mustard, the Dijon mustard—that reaction.

GRABER: Karl’s goal with this collection is to preserve the communities of microbes that make each sourdough unique. But for Karl, it’s also really fun.

TWILLEY: Karl is the keeper of the sourdough library. He can’t sell these starters or even give them away. Each unique microbial community still belongs to the baker who donated that starter in the first place. But Karl feeds them and takes care of them. And sometimes he plays with them, too.

DE SMEDT: I do take home some sourdoughs and I do some experiements and, yes, I do bake with them. And I discover some other things. Sometimes the fermentation power is totally different.

TWILLEY: When Karl is feeding the starters he puts them in small plastic buckets.

DE SMEDT: Some of them they just blow away the lid of these things. And other ones are just very, very slowly rising, fermenting. So there’s really differences in fermentation power, in flavor, in aroma, in the way the dough is feeling when you touch the dough, it’s different. So yeah.

GRABER: Karl’s point is that these starters are all different from one another. And the library itself is also unique. Nobody’s ever tried to conserve communities of useful food microbes for the future.

TWILLEY: Walking around the library, looking at these spotlit jars in their glass refrigerator vitrines, you really see each sourdough starter as a distinct, individual, precious thing. But how different are they microbially, really? Who’s living in those jars?

DUNN: Sourdough, in terms of the number of species we know how to grow, is toward the simple end. Often you’ll have two to four culturable bacteria species and one yeast species. It’s very likely, although we don’t know, that there are also things that are hard to culture in the lab that are in those sourdoughs, that make it a little bit more complex. But it’s toward the simpler end in terms of numbers of species. It’s not simple though in as much as different sourdoughs seem very different. And so if you were to look around the world, how many different species could you find in all of the sourdoughs? That’s actually a much longer list. And so an individual sourdough: simpler. This big picture of sourdough is far more complex.

GRABER: As Rob is explaining, a sourdough starter is an interesting creature, or, really, creatures. You can have a community of just a handful of different microbes that works perfectly together—as Rob says, maybe two to four species of bacteria, maybe one kind of yeast, and it’ll work. It’ll make sourdough.

TWILLEY: But what’s also probably true is that your sourdough starter could contain an entirely different community than mine, and they’d both still make sourdough. And it’s that diversity—that huge world of bacteria and fungi that can collaborate to raise bread—that’s what Karl is trying to collect.

GRABER: His library, as unique and impressive as it is, is probably just the tip of the iceberg. And maintaining this library is a lot of work—it’s not just collecting samples and putting them behind glass.

TWILLEY: Any baker can tell you what a commitment it is to keep a sourdough starter alive.

BARKER: I always describe it, if you have a sour culture, it’s like having a pet or a child, yeah?

GRABER: Paul Barker owns a bakery just outside London called Cinnamon Square. And he has many sourdough pets.

BARKER: You have to look after it. If you don’t feed it, keep it warm, or whatever. So unless you look after it, it will spoil, it will eventually die on you. So it’s a commitment to having a sour culture .

TWILLEY: In fact, there are even specialized sourdough hotels, where you can send your sourdough starter to be looked after if you’re going on a super long trip. A sourdough starter is really much higher maintenance than commercial yeast, so why do bakers use it? We asked Paul.

BARKER: Firstly, because the sourdough gives you a much different type of bread: different textures, more digestible bread, more nutritional breads. So I like the fact that you can get a totally different product. And you can be so creative with a sourdough, more so than a yeasted bread. So you can actually do a lot more with the shape in the baking, the decorations, I think—because you can get more from it whereas a yeasted bread, a commercially yeasted bread, you are just expanding your dough and baking it.

GRABER: Commercial yeast, as Paul explained—it makes the bread puff up, but that’s it. Paul knows that the microbes in his starter are giving him a different dough. It often has the right type of texture to allow him to play around more with the shape of his loaves. But what are those microbes actually doing to create these differences, and how are they doing it?

DUNN: So the microbes in the starter are starting to break down some of the hard-to-break-down things in the grain that you’ve given them to eat. And they are beginning to produce these gases that we think of as some of the really important flavors in the bread. But, as they metabolize the grains, they’re also also altering the structure of the carbohydrates that are present, which then is going to alter the nutrition of the carbohydrates, it’s going to alter the outside of the bread.

TWILLEY: As Paul has noticed and as Rob just explained, microbes improve the texture and the nutrition and even the look of the final loaf. They can even produce extra vitamins. But they also shape its final flavor—you can literally taste the difference between bread from different starter communities.

DUNN: And so butteriness—a lot of butteriness comes from which microbes are in your starter. The kind of sourness you have—how lactic it is versus how acetic it is—that comes from which microbes are in the starter.

TWILLEY: Rob told us that some sourdough bread has a particular gooey, melt-in-your-mouth feel that comes from a chemical called dextran, which is produced by a bacteria called Weissella. Weissella lives in some sourdough starters, but not in others.

GRABER: So: microbes are munching away on the flour, excreting things like buttery flavored lactic acid and yeasty farts that puff up bread. That much we know. But Rob and his fellow microbiologists don’t understand how all this microbial munching and excreting creates the differences between different finished loaves of sourdough.

DUNN: And the further you get down that chain of events, the less we understand about the mechanics of how all of that is happening. But what we do know is that all of the things that could influence those final flavors, final texture, final nutrition are things that we think of as predominantly microbial.

TWILLEY: So we don’t know. We really don’t know how the microbes are working their magic. We don’t even where they come from in the first place. But Rob wants to know. And so did we. And hence this giant 3-day experiment in Belgium. Which we have the exclusive first results from after the break.


TWILLEY: Back to Belgium. Where we are about to conduct an epic baking experiment in order to figure where the microbes that are in a sourdough starter actually come from in the first place.

DUNN: So, in order to make a starter, you take a simple set of ingredients and you expose them to open air and to your body and to your home, and it starts to grow. It’s like making a garden without ever planting the actual seeds. The mystery to me is: what determines which life forms are growing in that garden? And so that’s the fundamental mystery: why is your garden different from my garden when we use the same things to start with?

GRABER: Many bakers think they know the answer to this mystery.

VILCHIS: I think is flour. But the hands of the bakery is very important too to the results.

BAKER: I think it’s probably a combination of all of the variables.

MARCUS MARIATHAS: It’s mostly, in my opinion, the reaction within the flour and water. That’s where it starts.

BARKER: I would assume the environment is going to play a part in it as well. Because it’s going to be a lot of cross contamination in bakery from different flours anyway and you can end up with different types of sours.

MADDEN: I feel like every baker we talk to has a different assertion about where the microorganisms from that sourdough starter came from. Some people are very clear: it’s likely coming from the flour. If I use a different flour, I’ll have a different sourdough starter and a different sourdough starter must be different microorganisms. Some people have suggested that it’s the water. That’s why San Francisco sourdough is San Francisco sourdough and you can never make it in New York. There are claims about it being in the wood of buildings.

DUNN: What I like about this project is that as scientists we have not had to come up with our hypotheses because the community of sourdough makers has provided us with the longest possible list of what they might be.

TWILLEY: From that long list there are four main hypotheses: that the microbes that make each sourdough starter unique and individual come from (a) the wheat, (b) the water, (c) the environment, and (d) the baker themselves.

GRABER: Rob says we know that there are different microbes on different grains. Even within the same grain, there are different microbes on different strains of wheat—different heritage varieties, for example. Or wheat that is grown in different ways, like organic wheat. And then, even on the same plant, you can find different microbes in the germ of the grain versus the endosperm. The endosperm is what millers use to make white flour. So this means that whole wheat flour has different microbes than white flour does. Rob says these all these variables in the flour itself could certainly be influencing the sourdough starters.

TWILLEY: Then there’s the hypothesis (b), the water.

DUNN: Water can conceivably kill things in the starter. It’s unlikely to be adding things to the starter because we have a pretty good list of what lives in water. I think people are surprised often that all water they ever drink, even bottled water, has microbes in it, but they’re not the kinds of microbes we characteristically see in sourdough.

TWILLEY: In other words, Rob is saying that the water might prune particular microbes out of a sourdough starter garden, but it’s unlikely to be contributing any new microbes itself.

DUNN: The other thing though that that can then contribute to the starter is what falls from the air into the starter.

GRABER: This is hypothesis (c), the environment around you as you make the starter. Rob says that plants might have a particularly strong impact, because of the insects they attract and the microbes on those insects.

TWILLEY: And then there’s just the bacteria that are swirling around in the dust and air. Some of those come from pets, if you have pets. The majority of them, usually, come from your own skin and the skin of the people you live with.

GRABER: And finally, hypothesis (d), the baker.

TWILLEY: Specifically, the microbes living on the baker’s skin.

DUNN: We can think of many ways that microbes differ from one person to another person.

TWILLEY: For example, there’s that gene that determines whether you have sticky or dry earwax.

DUNN: And depending on which version of that gene you have, your skin microbes in your armpits, but also around your body more generally, are super different.

GRABER: There are also microbes on your skin that don’t live on your skin. They get there when you touch parts of your body that have other microbial communities. Like your gut microbes.

DUNN: And then we know that human women and human men differ greatly in microbes because of vaginal microbes. And so women have way more Lactobacillus in general, but especially in vaginal communities, and those sort of travel around through the day-to-day business of being a human.

TWILLEY: These vaginal microbes are particularly interesting because Lactobacillus is a key part of most sourdough starter communities.

DUNN: Yes. So, in some cultures, sourdough is mostly or exclusively something that women bake. And to me it’s really intriguing to think about does that have something to do about the unique sourdough community that emerges when women make sourdough versus when men make sourdough.

GRABER: This three-day Belgium adventure, the experiment we’re watching unfold—it’s designed to try to tease out where the microbes in the sourdough come from. A, B, C, or D.

TWILLEY: To be precise, it’s designed to isolate two variables from these four possible sources for the microbes in sourdough—the microbes on the different baker’s hands and in their environment. Those are the variables.

MADDEN: They were shipped the ingredients, they were given the same protocol, the same recipe.

GRABER: That is, these bakers were shipped exactly the same flour. Not the water, because based on the existing research, Anne and Rob don’t think the microbes in water plays a big role.

TWILLEY: Anne and Rob cultured the microbes out of that flour, so they already have a list of the microbes that are being contributed to the starter from the wheat.

GRABER: Like Anne said, the bakers were given very specific instructions about exactly how much flour and water to use and exactly how long to ferment their starters. The goal is to make this all as controlled as possible.

TWILLEY: So all these bakers, men and women, in different parts of the world, they all made their sourdough starter using the same flour according the same protocol. And then they put their starters in a baggie and they brought it with them to Belgium

MADDEN: And that was a really fun part, when we got to open them all up and they’re coming in and some of them smell like vinegar and some of them smell more like yogurt and some of them smell creamy.

GRABER: As soon as the bakers arrived, Anne and Rob opened packages of sterile swabs, like super long Q-tips, to get samples of those rich microbial communities in the starters.

MADDEN: Just one double swab per.

GRABER: Then we took a break from the science. We all introduced ourselves and met each other, and everyone talked bread.

TWILLEY: The final part of the experiment that day was refreshing the starters, according to the protocol.

BAKER: I’m going to put my starter in this bowl, first of all dilute it with the water, and then add the flour on top, mix it, put it back in here, and then we’ll wait until tomorrow.

GRABER: And that’s it?

BAKER: And that’s it.

TWILLEY: And then we all ate dinner together accompanied by lots of bread, and day 1 of the experiment was over.

GRABER: First up day 2? After breakfast featuring lots of bread, we got to everyone’s not-so-favorite part—getting swabbed to find out what microbes live on their skin.

TWILLEY: Paul from London was up first.

MADDEN: Now, I’m going to be swabbing your hands, and I’m going to ask that put your hands out just in a way that I can apply some pressure. And I’m going to spend a few seconds.


MADDEN: Just going over the front and then I’m going to ask you to flip and then I’ll do the back. And if we could not talk over the swab when it’s out so that we can not introduce some of our oral microbes.


MADDEN: Thank you.

TWILLEY: Anne was swabbing the baker’s hands because if any microbes are going from a baker’s body into their sourdough starter, they are probably getting in there via their hands.

DUNN: You know it will be wonderful in some future version to you know top-to-bottom swab all these bakers and really start to tease out, you know, which body part is really contributing. But we had to start somewhere and so we started with the hand connection.

GRABER: In case you’re getting a little grossed out, don’t worry. The bakers do wash their hands. And they should wash their hands. Anne made sure to emphasize that. Even after you wash your hands though, there are still microbes on them. They’re everywhere.

TWILLEY: So, next step: after their hands were swabbed, the bakers were allowed back into the test kitchen to be reunited with their starters. Which they could hardly wait. It was like parents at the kindergarten gate. But before they could be fully reunited, the starters all had to be tested with some cool science gear, to find out their pH and their organic acid content.

TWILLEY: Once again, the sourdough starters all looked—and smelled—completely different.

KASPER HANSEN: My sourdough is called Danish Dynamite.

GRABER: That’s right, Danish Dynamite.

CASPER: So a lot of activity inside. So, as you can see, up side of the glass here.

TWILLEY: It was like looking at baby photos, I’m not kidding. Everyone thought theirs was the prettiest of all.

GRABER: You’re smelling your sourdough?

TOMMASO RIZZO: Smell is buttermilk—smell, taste, aroma.

GRABER: Can I smell? Mmm, yeah, it’s got a little sweet. The bakers made their bread and left it to proof overnight. And, as that official science-experiment bread was rising, the bakers were set free in the test kitchen to let their pent-up creativity run wild.

TWILLEY: And they went to town. Hakan made this crazy Turkish bread that had lots of melted cheese and a cracked egg on it. Leticia, the Mexican baker, she was putting cocoa and raisins into a sourdough loaf. Someone made pita bread.

GRABER: I’m going to taste some of this. Mmm. Nicky, hot pita with garlic butter? It’s really good.

TWILLEY: It’s really good. That’s good. So look, let me do this.

GRABER: Mmm, the smell.

TWILLEY: I’m squeezing the bread like it’s a bellows on an accordion or something. Or trying to light a fire. This is what I’m doing.

GRABER: That smells amazing. It’s like as you squeeze the dough the scents in the air pockets just, like, get blown right at your face.

TWILLEY: So I stood here. Stavros, like, pumped the bread in my nose, and Vassilis was like “This is sourdough.” We sniffed bread and we ate bread, and then we ate more bread.

GRABER: And then we ate dinner. Which also had some bread.

TWILLEY: And then we rose bright and early on the third day, had some bread for breakfast, and went back into the kitchen to bake the science-experiment bread. But… there was some tension.

GRABER: Tommaso, for one—he’s from Italy—he didn’t want to put his bread in the oven when everyone was told it was oven time. He said the dough wasn’t ready for baking—it hadn’t risen enough. Rob whispered to us that he and Anne were having a hard time making sure that all the bakers kept to the scientific protocol.

DUNN: Yeah. So we’re thinking about it right now. There’s a tension between what people view as counting as a bread. And, uh, what we want.

TWILLEY: Tommaso was overruled. In the nicest possible way. And all the bakers’ dough went in the oven at the same time. And the same way that their starters had looked and smelled really different, despite having been made from the same flour using the same instructions, the dough looked really different as it went into the oven, too.

GRABER: You could see some really big air bubbles in some and none in others. Some rose a third of the way up to the tops of the baskets, some rose all the way to the top. Some were super bubbly on top, some were shiny and smooth. And then the bread came out of the oven.

GRABER: Oh. Those are pretty. (OVEN DOOR CLOSING)

TWILLEY: Some of the bakers were happy and some were not. So these are Tom’s, you like the look of them?

WALTER: I like them. Because when it’s cracking open, you see black line. And Karl calls it eyeliner—so we have to bake it so—eyeliner on the bread.

TWILLEY: And eyeliner is a good thing, right?

WALTER: Yeah, yeah.

GRABER: I learned something new—I never knew bread should have eyeliner on it. It’s basically the nice, dark, cracked edge you see at the top of the loaf. Tom’s loaf had really lovely eyeliner.

TWILLEY: This has a lot of nice fish eyes or blisters.

GRABER: Little bubbly blisters on the cooked crust are another sign of a great sourdough. But some loaves didn’t look as good. Like Paul’s. And this one doesn’t look like it did very much over here, it didn’t even crack.

TWILLEY: Which are yours?

BARKER: The ones that are looking very sad at the back. The two behind this one here.

GRABER: No, they’re not very…


TWILLEY: And then, as soon as it was cool enough, all of the loaves were sliced in giant bread-slicing machines. And the bakers were asked to evaluate a slice from each loaf. They had to assess its appearance, its smell, and, of course, the way it tasted.

TOM REES: So we’ve got kind of two different colors, I see already. One which is a bit grayer, and one which is a bit more yellowy, creamy color.

TWILLEY: And is that reflected in differences of smell too?

REES: Yeah, so the greyer ones—the greyer ones have less of an acidic aroma

BARKER: Some are creamy and some have gone kind of more reddy, kind of browny, sort of hints. So there was a distinct difference in the color, which is quite interesting. I wouldn’t have expected that considering we are all using the same flour, the same ratios of ingredients.

BAKER: Like the one of Guillermo is dense and stronger, and from Tom, it’s very fragile and very open. But the taste and smell is about the same.

VILCHIS: For example, Hakan is very very similar to Kasper. I think is the same bread. Incredible. Paul is the same than Guillermo.

HANSEN: It’s much more like wheat—not so fruity. Hakan and Tom, taste more—have more acid taste.

DUNN: And so in this case we know that all those differences from bread to bread are really microbial.

GRABER: But it might not actually be because the starter contained different microbes. The exact same microbes can create different smells and tastes just based on the temperature that they grow in, for instance. So these results, that the breads smell and taste different? Could just be because the temperature in London is different from Guadalajara.

TWILLEY: Sensory evaluation was not enough to answer this question. Instead, Rob and Anne had to take to their swab samples back to the lab and analye them.

GRABER: A few months later, we called Rob up to find out how it all went. (PHONE RINGING) Hey Rob! So Belgium ended. You packed up to go home. How did you feel?

DUNN: I felt super full.

GRABER: I felt really full, too, just so you know.

TWILLEY: I was never going to eat bread again. And then I did.

DUNN: No, I’m ready for more bread to be honest. There’s been time.

TWILLEY: Science takes time, but this science took a little bit longer than Rob wanted because his samples—the swabs from the bakers’ hands and the sourdoughs starters—they got held hostage in Belgium. Trying to get these kinds of biological materials across borders can be tricky. Rob is a patient man, but even he was getting a little frustrated.

DUNN: And then, amazingly, just last week, we got the first results from that decoding of DNA.

GRABER: Rob, Anne, and their whole team spent a day just marveling at the data and poking around. They were trying to figure out if they could make any sense of the data just by looking at it. Which, of course, they couldn’t.

DUNN: But then eventually we started to formally analyze what’s going on with the patterns of the data and that’s where it starts to get interesting. And so the first one of those analyses happened on Friday and the second one happened about two hours ago.

TWILLEY: So tell us! What did you find?

DUNN: Well, the first thing last week was a result we weren’t looking for, we didn’t anticipate. And I had no idea it was even possible.

GRABER: It’s about the bakers’ hands. Normal hands usually have Staphylococcus, and some armpit microbes, some bacteria that are the same as acne bacteria, maybe some random bacteria from things you’ve touched recently.

DUNN: When we looked at the bakers’ hands, their skin bacteria on their hands was about half sourdough bacteria. And so they, like, have sourdough paws.

TWILLEY: Sourdough paws!

DUNN: We’ve looked at zillions of hands. We’ve never seen anything like this. And so the first result is that the bakers themselves have changed in response to their occupation.

TWILLEY: Normal hands like mine and Cynthia’s and Rob’s—they are something like 2 to 4 percent Lactobacillus.

DUNN: On the hands of the bakers, it is like it’s the star of the show. It’s wild. I mean, if it’s right, you should be able to put flour and water on a baker’s hand and it should start to ferment immediately and become acidic.

GRABER: Working with sourdough has entirely changed the microbial environment on the bakers’ skin. They’ve been colonized by their pets! Rob wonders if the bakers spend so much time with their hands in acidic dough that the sourdough Lactobacillus microbes end up with a competitive advantage over normal skin microbes.

TWILLEY: So that is weird. But it’s not what Rob and Anne set out to find. What they were trying to understand from this 3-day Belgian breadfest is whether the microbes in the sourdough starter come from bakers’ hands—not whether bakers’ hands are somehow different from normal hands.

DUNN: So what we saw two hours’ ago was that there’s a group of bakers that has very different sourdoughs, and the unusual microbes in those sourdoughs are also on their hands.

GRABER: One question answered. The bakers who have weird bacteria on their hand have the same weird bacteria in their sourdough. There is a connection. Individual bakers do indeed seem to influence their starters. But so, does this difference influence the flavor of the resulting bread? Rob doesn’t know, he hasn’t done that research yet, but he has a hunch.

DUNN: I predict that second group has more unusual flavors. And we should be able to capture that. We’ll see.

TWILLEY: Stay tuned. Meanwhile, what Rob and Anne have done is sit down and compare the list of microbes that were in the flour and the list of microbes that were on the hands and the list of microbes that were in the starters.

DUNN: We get a total of about 193 kinds of bacteria in the sourdoughs. which is a lot more than the bakers tend to think is there, which is interesting in and of itself. Something like 80 of those are also found on hands. And roughly the same number seems to be found in the flour. And there’s overlap between the flour and the hands. We saw almost nothing in the water, so they’re probably not coming from the water.

TWILLEY: But they did see some microbes that weren’t accounted for, that were not from the hands or the flour. They were maybe microbes that were just floating around in an individual baker’s kitchen.

DUNN: Yeah, they could come from a leaf outside the bakery. It could come from a bowl or a spoon. But it’s not so surprising that we haven’t found where all those microbes are coming from—and, in some ways, that leaves the bakers some magic. Where does the stuff we’ve not measured yet coming from? Just magic. You guys can keep that.

GRABER: Rob also told us another new finding that totally contradicts what he told us back in Belgium, earlier this episode. Remember how he said that sourdough starters have three or four species of bacteria and maybe one species of yeast? Rob says based on these new samples he’s seeing ten species of bacteria in the average sourdough starter and maybe three species of yeast.

DUNN: We now have enough data to say that I was wrong when I was describing the simplicity of the starters. Which also means the whole literature is wrong.

TWILLEY: Folks, this is science in action. We think we know things, like about how many species of microbes live in a sourdough starter, and then we do some research and discover we don’t. But Rob pointed out that sourdough starters are still not particularly complex in microbe terms.

DUNN: And so part of the story that’s super fascinating to me is, you put out flour and water, all around the world, and somehow you can create a very similar ecosystem out of what for bacteria and fungi is a relatively small number of species. If you put out sterile soil in this many sites globally, you’d be looking at 20,000 species. And so, on the one hand, the individual starters are more diverse than we tend to think. On the other hand, that global picture is actually a lot simpler. So that was really interesting.

GRABER: Rob and Anne and their collaborators have really only just begun analyzing this data. Over the next six months, they’re going to be figuring out what types of compounds each species of bacteria can produce—not necessarily that they’re actually making those compounds in the starters, but that they can.

TWILLEY: And then they’re going to match those compounds to their possible effects in bread—different flavors, different textures, different nutritional values.

DUNN: The other part is we’ve barely touched the fungal data. And so that will mean we’ll be spending a fair amount of time on that even this coming week.

TWILLEY: So there’s much still to be done with just the data from our Great Belgian Bake Off. But there’s also just more sourdough research to be done in general. Our Belgian breadfest was only one of the sourdough experiments Rob and Anne have got going on the lab right now.

GRABER: They’ve already gotten about a thousand people from around the world to send in their sourdough starters. Rob and Anne want to get a big picture of sourdough diversity. They’re hoping to see patterns, like whether some species are more common in some areas of the world. And they’re already starting to see some results.

TWILLEY: Rob told us that, in terms of bacteria, there seems to be a shared sort of pool that colonizes grain and water mixtures all around the globe. In other words, the same bacteria are pretty much everywhere and then which end up in which starter seems to depend mostly on the flour and the baker, as we just learned.

GRABER: But they are seeing a little bit of geographic variation with bacteria. Some bacteria tend to live in more northerly Scandinvanian countries, for instance. That’s not the only anomaly.

DUNN: There’s a little bit of a hint so far that maybe France is kind of special.

GRABER: France is special.

DUNN: But the fungi we’re seeing globally have a lot of geography. And so there’s one one kind of yeast—a kind of fungus—that we’ve basically only seen in Australian starters. We know that the yeast can do a lot in terms of flavors and aromas. If that unusual yeast is playing a big role, then there could be a flavor that you could only actually savor when you’re in Australia. And we don’t know that yet. That’s a fun idea.

TWILLEY: Sourdough tourism is going to become a thing, just wait and see.

GRABER: One of the things Rob and Anne are going to do over the next year is bake some bread from these thousand starters that they received. That way they can start to assess flavor while controlling for the other ingredients. The ultimate goal is to arrive at microbial recipes for sourdough deliciousness.

DUNN: Once we do that, that will be the hope—that there is some mix that really gives you the perfect butteriness or the sourest souriness. Is souriness a word? I don’t know.

GRABER: Rob and Anne are also working with colleagues to tease out the evolutionary history of sourdough. They’re going to be working out how microbes in starters change over time. So, eventually, they’ll be able to tell you, if you’re using your great-grandma’s starter, are those your great-grandma’s microbes? Or, as listener Danae asked, if she gives her sourdough starter to a friend, will it change—and if does, how quickly?

TWILLEY: So there’s still tons to figure out about sourdough, but Rob is on it. And we’ll keep you posted as his results come in. It’s super exciting research. Not just because we love microbes.

GRABER: A round of applause if you haven’t keeled over yet from taking a shot every time we say microbes!

TWILLEY: We do love microbes, But we also love this research because it points the way to a future of even more delicious bread!

MADDEN: And so I think the question is the next step, which is: What microorganisms create what flavors and aromas and traits in bread that we want. And then we can start tracking down what microorganisms might be leading to those traits. And so you can imagine a future where you could think about the kind of bread you want. Maybe I want it to be crusty and kind of chewy with fruity notes. And by having that choice of bread, there’ll be a list of species that will work together to create that. So you’ll have a designer sourdough.


TWILLEY: Thanks this episode to the Burroughs Wellcome Fund for supporting our reporting on biomedical research.

GRABER: Thanks also to some of our Supreme Fan level Patreon supporters: Andy Allen, Lori Schultz, Justin So, Robert Wells, Alex Sol Watts, Eric Schmidt, Corinne Lewis, David Kohn, Matt Rooney. We cannot thank you enough for your generosity in helping keep Gastropod going.

TWILLEY: And a big thank you to Puratos, who hosted this experiment but also hosted Cynthia and me in Belgium. We have photos and links to Karl’s magical Sourdough Library on our website, gastropod.com

GRABER: Thanks so much to Rob Dunn and Anne Madden for letting us follow them around for three days and try not to get in the way of all their swabs.

TWILLEY: And thanks also to the lovely bakers, who couldn’t have been more of a fun group to hang out with while doing some cutting-edge science. And some competitive-level eating.

GRABER: We are going on a brief break over the holidays. But we’ll back in 2018. We have an amazing season lined up for you. If you’re on our sustaining supporters list, you’ll get a sneak peak at what’s coming up. Thanks to all of you who listen, who support the show, who write in, who take part in our Shareathon—we do this for you, and we couldn’t do it without you!
crumbs to try to identify their microbes. Could those microbes be the same as the ones in sourdough today?