Radiolab - Guts

Episode Date: November 4, 2022

This hour, we dive into the messy mystery in the middle of us. What's going on down there? And what can the rumblings deep in our bellies tell us about ourselves?  We join author Mary Roach and reach inside a live cow's stomach. Talk with writer Frederick Kaufman about our first peek into the wonderful world of human digestion that came about thanks to a hunting accident. And explore with show regular, science writer, and fellow water drinker, Carl Zimmer, about the trillions of microscopic creatures that keep us regulated, physically, but also, maybe, emotionally and spiritually. Our newsletter comes out every Wednesday. It includes short essays, recommendations, and details about other ways to interact with the show. Sign up (https://radiolab.org/newsletter)!Radiolab is supported by listeners like you. Support Radiolab by becoming a member of The Lab (https://members.radiolab.org/) today.Follow our show on Instagram, Twitter and Facebook @radiolab, and share your thoughts with us by emailing [e-mail]. Leadership support for Radiolab’s science programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a Simons Foundation Initiative, and the John Templeton Foundation. Foundational support for Radiolab was provided by the Alfred P. Sloan Foundation.

Hey, I'm a lot to fnassar. This hour, we dive deep into the vault back to 2012 to explore the grotesque tube slide that lives inside all of us. I mean, it seems straightforward, right? It should be like every day, several times a day, put food in your mouth, sometime later, comes out the other side, but what really happens in between? Now, I so vividly remember listening to this episode when it came out, when I still love about it, is just this idea that one-errant gunshot wound opened up this portal for us to peer inside ourselves

and to see what's actually going on in there in real time. And that what we saw upended so much of what we thought we knew about the kind of messy mystery in the middle of us. I have a feeling, call it a gut feeling, that you're going to enjoy it. So without further ado, I give you guts. Best enjoyed after a meal. Yeah, wait, wait, you're listening.

Okay. All right. Okay. All right. You're listening to Radio Lab. Radio from WNYC. Hey. Yeah.

Rewind. Hello. from W and Y. Hey! Hey! Three, Y! Hello! We're gonna start this show today. Hey Mary. With Mary Roach. Hey! Tim here.

Hi Tim. Hey let me see if I can... Mary is one of our favorite authors, mostly because she kind of writes about stuff that's... Yuki Gross. I'm the kind of person if I find myself in an operating room for whatever I'm reporting on, I'm the kind of person where they'll be like, Ms. Roach, you need to step back. Your head is actually inside the body cavity. And for her latest book called Gulp, she got really, really into and inside cows.

Yeah. The fistulated cows that the agricultural schools have. And what's a fistulated cow? A fistula is a irregular anatomical passageway. And a fistulated cow, in this case, has a hole and opening right in its side so that you can actually stick your hand into its side and reach all the way down to the stomach. This is the living cow, right? It's a moving... This is a live cow. And you've done this? Yeah, it was. It was this amazing because really, you know, a cow is a...

She did it at the University of California Davis. You're just, you're standing there and sort of normally and for some reason I've worn a skirt and kitten heels and I'm, my host are wearing manure encrusted muck boots and there, this is source of great entertainment that I hear and it's packed really tightly you got to really work your arm the guy I was with Ed de Peters and he's like no keep going keep going I'm like I don't know Ed I'm not sure really go further in yeah keep going keep going and I'm literally up to my shoulder inside this cow I so want to do that where are you guys we're in New York yeah I know where this one out. I so want to do that. Where are you guys?

We're in New York. Yeah, I know where there's one out there. I can get you a fist-deleted cow. You want to walk him down to it to burn and I'll build it the group? I didn't actually get to do it unfortunately, but we sent our producer Tim Howard out to Rutgers University,

where a bunch of high schoolers had come to see. Lily, Lily, the fisculated cow. Okay, let's give it a go. I'm gonna pop the cork. All right. Did he say cork? Yeah, you have to un-cork the hole in the cow. Can you seal the steam coming out?

Ready? All right. This is Tim reaching his hand in. Go straight across the top to the far side. Okay. Oh my god. It's powerful in there. Oh my God. It's powerful in there. Oh God.

I mean, I was a little worried it was going to break my hand. What made you like pressure? It's a very muscular organ. It's squeezing my arm. Mixing and I can feel the side of the stomach pushing it against me. Squeezing and contracting. Whoa.

Three hours of squeezing. Really squeezing. It's groping you back. I'm stuck. Right. I'm just gonna try to go a little bit, a little bit deeper. And it's hot.

It's steaming. I don't know. It's like bubbly and, it's cool. It's very, yeah. And she is so calm right now. I can't believe it.

Like how's bored? And I've got this look on my face like I've seen God or something. I'm like, wow. Oh. Mary says that for all her times in morgues and in all the places she's been, this one was really different. It was the expression I was wearing.

I'm sure I've never had cause to use. And here's why. If you think about it, the stomach is a center of magical transformation. That is Fred Kaufman who wrote a whole book about the stomach. You take something outside of your body, you put it in your body, and it turns into you. So it's like this conduit between

what's outside you and what's inside. The other thing that's weird is that the human body is a torus, we're donuts, we've got a hole going through the middle of us, all the way through us. So what seems to be inside us, what seems to be inside our stomach, actually is always outside us. Oh, this is getting so deep. You don't like the darts? No, I mean it's great. I think I'll go with it. Because I was thinking we could start that way.

Because that's what we're kinda doing this hour. We're gonna take this thing that's deep inside us. And turn it inside out? Yeah. I'm Janna Bumrant. I'm Robert Krohich. This is Radio Lab and today, guts, that mystery that lies between our mouth. I'm Chad Abumrant. I'm Robert Kroich. This is Radio Lab and today, Guts!

That mystery that lies between our mouth. And... our butt. Sssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssssss And from centuries, nobody really knew what's going on in there. But then something happened that opened up a window. Yeah. Do you want to start back at the beginning of it? Yeah, let's once upon a time. OK. So.

Once upon a time. It all begins. And when is this? They first met in 1822. Once upon a time in 1822, there was a guy named William Beaumont. William Beaumont is a farm boy from Lebanon, Connecticut, five brothers and six sisters. And William clearly is the smart one. He was the one with the big dreams.

So at an early age, he leaves home and gets himself a job as a doctor. An army doctor up north. At Fort Mackenac, which is this, it's a trading post basically. So Boma, he has little doctors office at the top of this hill and at the bottom. There's a general store for fur traders who would come in from Canada. Super hardy dudes, like it's cold up there and they're going out in canoes

and they're running with these huge packages of fur on their backs. I imagine big beards. Sure. In any case, that was all just set up. Here's the actual story, one day. June 6th, 1822. Normal morning. All the fur traders come in and are unloading and loading and getting

their coffee, salted meat, supplies to go out. Trepsum fur went all of a sudden. Right outside the shop. Somebody's gun went off. Somebody calls Beaumont Beaumont. Dashes out the door. Runs down the hill. Finds this guy. This 18-year-old kid. Really in bad shape. The kid's lying on the ground. He's a big guy, muscular, but he's covered in blood. And he has a hole right below his ribcage. About the size of the palm of a grown man's hand. Nobody was sure what happened, but someone's gun had gone off. By accident, and shot this boy, point blank. His lungs are dripping out.

There's blood. This is what Beaumont sees when he shows up. This is what Beaumont sees, and the other thing Beaumont sees is food coming out of his stomach. Meet and bread into coffee. Basically, the remnants of his breakfast spilled out. On the ground, right in front of him.

You can kind of see the gears turning in Beaumont's head as if he's thinking, Whoa. There it is. Digestion in action. Which was kind of disgusting, but it was also something of a revelation because in 1822, the stomach was an area of mystery. Just like today, we're aware the brain is an area of mystery. Just like today we're aware the brain is an area of mystery. And for centuries, people believe that the stomach,

more broadly the gut, was in a very real way the center of our beings. Yes, in Puritan times, the bowels are the seat of human sympathy. You know, like where are deepest feelings come from? Few of bowels for somebody, that means you sympathize with them. Oh, is that something people would say?

Absolutely. We should bring that to them back. That's very interesting. I have bells for you. Point is, medical science was pretty fussy in what happens down there. I mean, they knew it was important, but they had no idea how it worked.

Like, how does food become us? Nobody understood it. Does it can't see? You can't directly observe it without opening the person up. But here was a guy open right up. But of course, Beaumont is a doctor so he's like, wait, I've got to save this guy so we start sowing him up frantically. Pretty sure this fellow is not going to make it. And he was surprised that two days later the guy was alive.

Really surprised. And as the months passed, this kid, St. Martin, that was his name, Alexis St. Martin, he gets better, but a year later he still has his hole in his stomach. The hole never closes. What happened is he grew a fistula. Just like the cow we talked about earlier, except in this case he didn't have a quirk where he was wounded. He had a flap of skin covering the hole if you wanted to, he just pulled back the flap and look inside. And we don't know if Beaumont left it that way on purpose.

What we do know is that he sees an opportunity to make the body give up its secrets. He sees he's got something that nobody else has. Maybe he even thinks. This man could be my ticket out of being a lowly Fort Mac and Act doctor. So Beaumont kind of hires him as a man around his house. As a man servant.

You know, he said, oh, I was a charitable thing. I wanted to help him. You know, because it couldn't work. And I'm thinking, no, no, no, no, no, no, no, no, no, no, no. And so about a year later, he starts. I'm in. Wow. He starts his experiments.

Oh, my Lord, this is straight out of a movie. While reporting this story, we ended up visiting the rare book room at the New York Academy of Medicine, which is pretty much the coolest room ever. It's all mahogany and they've got ancient skulls sitting on top of bookshelves and the books are... Hundreds and hundreds of years old. In any case, the librarian Arlene Schainer showed us around and then put on some white gloves, disappeared between some stacks and came out. But here we have with a little purple book. Beaumont's observation. Experiment one is on August 1st, 1825. So at

12 o'clock I introduced through the perforation into the stomach the following articles of diet. So what he does is he he takes different foods a piece of raw salted fat pork some corn beef you know like a one inch square of corn beef a piece of stale bread and he attaches them to a silk string and he inserts them through the artificial opening into the stomach into the stomach for an hour then he takes it out like a fisherman yeah yeah he's fishing he's he's he's doing stomach fishing and he takes it out and he records you know so an hour, then he takes it out. Like a fisherman? Yeah, yeah, he's fishing. He's doing stomach fishing. And he takes it out and he records, you know. So it was an hour later.

How much was digested? With Drew and examined them, found the cabbage and bread about half-digested, the pieces of meat on it. This went on for hours. Returned them into the stomach. At two o'clock, PM withdrew them again. And hours. Returned them into the stomach. At two o'clock, PM withdrew them again. And hours. Return them into the stomach again.

For years. Over the next few years, Beaumont puts anything he can possibly think of into that stomach. Pig's feet sourced, take an hour. Animal brains spoiled, take an hour and 45 minutes. Fresh eggs, hard boiled, take three hours and 30 minutes. Soft boiled, take three hours. Fresh eggs fried, take three hours and 30 minutes. Soft boiled, take three hours. Fresh eggs fried, take three hours and 30 minutes.

Fresh eggs roasted, take two hours and 15 minutes. Look, it's just the totality of food in America at that point. Whipped eggs take an hour and a half. He's trying everything. Bigged custard takes two hours and 45 minutes. Oh my God, it goes on some pages. Go on and on.

Alexis St. Martin is becoming increasingly irritable about this whole process. I would imagine. Because a lot of the times, the things that Beaumont went stick into his stomach would make him sick. Given a fever, pain in his head, depressed pulse dry skin, coated tongue, and numerous. So in 1825, three years after this all started, St. Martin

finally bolts. Goes back to Canada, gets married, even has a few kids. All the while, Beaumont is writing him letters, trying to lure him back. And he was offering him, okay, I'll pay for your family, okay, I'll give you $50 a year, okay, I'll give you $75, I mean, he kept, and he was like, I'll throw in the lamp. Because you know, he still wanted to know, like, all right, fine, it takes. Three hours and 15 minutes to digest a carrot.

Boist your soup, three and a half hours or soup whatever. But how does it work? How does the stomach do it? And eventually because he needs the money, Alexis St. Martin does come back. Beaumont starts his experiments again. And one night, while Beaumont is peering into the boy's stomach, he gets his answer. He says he applies a few crumbs of bread to the inner surface of the stomach immediately afterwards. Small, sharp papillet became visible.

He saw a little pimples form on the wall of the stomach and out of the pimples. Zooted a clear transparent liquor. Outscore some juice. Outscore some juice. And that was it. That's the magic juice. Clear, almost transparent. Taste it a little saltish and acid. Ooh, my mouth light to the tongue.

Yeah, tasting, a lot of tasting went on. And then, you would collect the stomach acid and see if you could digest outside the body. There was this theory that the body had this vital force and that that was necessary for the bodily processes including digestion. So if you took the stomach acid out, what would happen? December 14, 1829. At 1 o'clock PM I took 1 and a half ounces of gastric juice fresh from the stomach, put into it 12 drums recently salted beef boiled. The theory at the time was, oh, it wouldn't work. You had to have the magical powers of the human body. But digestion commenced.

Boma, one of his big discoveries, was, no, you don't. That actually there are no secret forces of sympathy and excitement driving things. It's a chemical. That's what it's all about. Now Beaumont didn't know it, but that juice he was seeing, which he called, gastric juice.

Those are enzymes. And what enzymes are like little chemical scissors, they break down food so that you can take something in from the outside like this carrot. And absorb it, but it comes literally a part of you. The key to the whole thing, the key to life, are enzymes. In a way, they are the magical force,

just in chemical form. That's it, that's the truth. He was the first to understand it, the first to see it, the first to figure out the method of how to prove it, and he proved it. So, Beaumont writes a book about this. And this book is published in 1833. And he becomes famous.

People were fascinated by Beaumont's experiments. He would go on these tours. He's called over to Yale University, gets invited to speak in Europe with his, wherever he goes, he brings his gastric juice and he lets him through. From the dude's stomach? Yeah, yeah, he travels around with it.

And whenever he could, he would take St. Martin with him. St. Martin was his PowerPoint. And he's like, I need you, man. I need you on the stage so everybody else can come up and stick their tongue in your stomach. For William Beaumont, this works out pretty great. He's thought of as this, you know, tremendous contributor to the understanding of digestion. As for Alexis St. Martin, he was curiosity. He was medical curiosity.

For the rest of his life, for the day he dies, even in death, his body is a hot commodity. And his family was very aware of this. They let his body rot in the sun for three days and then buried him very deeply and put big rocks over him so he would not be exhumed. Thanks to Arlene Schener at the New York Academy of Medicine and Fred Kaufman who wrote a book called A Short History of the American Stumic.

And a special thanks to Mary Roach, her forthcoming book is called Gulp, a trip down the elementary canal. Hey, I'm Chad Abumrod. I'm Robert Kroich. This is Radio Lab and today. Well, we're talking about the interior space that runs down from your much to your butt and it is called. You got it.

You might. What is that? It's just an old person's word for her mouth. Anyhow. What? What is that? It's just an old person's word for her mouth. Anyhow. Now, as we just heard for a very, very long time, people believed that the stomach was a place of magical transformation.

Yeah, but of course, as we know now, it's just a big muscle with acid and enzymes and stuff. But if you travel a little deeper down, down below the stomach, Then things get spooky again. We have these sort of shadowy images of what's going on in there. That's Carl Zimmer, a shadowy figure himself, a science writer. Can I get more water? Yeah, and a frequently thirsty map.

I throw a guy on the scratchy. Soren and I called him up, you know, while you were gone, on paternity leave. And he told us, you want a mystery? Yeah, I do. OK, then the stomach is just a warm up. Oh, yeah. The 25 feet of coiled, soiled, fetid tubing inside you. Give me the intestines.

Yeah, yeah. That's where the real mystery lies. You know, because here's the riddle. The part of you that turns the world outside into you, isn't just you. It's more like a collective. What does it mean by that? Well, if you zoom into our intestines, what you'll see is legions of tiny creatures. Bacteria, viruses, fungi, protozoans.

And those are all little single cell. Kind of guys. Yeah, we're talking about non-human things inside of me. How many of you got, would you say? Me? Yeah. Probably in the order of maybe a couple thousand species. So there's E. coli.

Bacteriodes for jillies. And then another one, another one, another one. It's a whole universe stuff. Yeah. Microbacteria, travel bacteria, vercinia, the follow caucus, chromobacter,

as you go to the fuzz, the hero mode. Some of them you'll find in all of us. And then there are just a whole bunch of other species that are rareer, might be one person and not the other. It's like a rain forest. Oh yeah. There are ecologists now studying your gut.

We're looking at these complicated networks of Hundreds thousands of species that are living inside of you and depending on each other or praying on each other It's just this incredibly complicated pattern that scientists haven't figured out When you're in it embryonics in a what are they called the sacs? Your amniotic sac your amniotic sac. How much bacteria do you have in and about you there? Uh, you're sterile. Which, you have none? No.

At all. You're clean. Huh. But then, as you are coming out, all of a sudden, you're into this new environment, the birth canal. Your breathing, your mouth is open, stuff is coming into your mouth that's

coating your skin. There are lots of bacteria there, vagina of the birth canal. It's a very complicated ecosystem there. And right after your born says Carl, you meet a nurse and some doctor who got home, they'll play in your backyard, you'll suck on a shoe. You might eat some dirt and get licked by a dog. And by the time you're going to school, you've got probably about 100 trillion microorganisms. So 100 trillion other kinds of cells in you? Yeah. So if you were to take like all the bacteria in your body

and just made them into one lump, it would be about three pounds. Oh, really? Think of it as an organ. I mean your brain's about three pounds, you know, hearts a pound or two. So this is another organ. In this case, it's an organ that helps you digest food, but here's the thing. This place in you, which is filled with foreign critters, somehow this organ gets into your head. What does that even mean? Wait, you just wait a second. Let me introduce you to someone. Hello, can you hear me? Yes, yeah, we can hear you. John, my name is Professor John Crine. I'm the professor in chair of anatomy and neuroscience here at

University College, Cork in Ireland, and I'm a neuroscientist. A brain guy? Yep. If someone told me six years ago, it's a neuroscientist that I'd be here talking about microbes, I would have laughed it off. But to make a long story short, John found that as he was getting into neuroscience, a lot of the neuroscientists at his university in Cork in Ireland, they were getting into bugs for reasons that will become apparent in a moment, And eventually, he got the bug for bugs. And began to work with this one particular strain of bacteria.

This is the lactobacillus strain. What was it, lactose something? Lactobacillus, sorry. Lactobacillus ramenosis. It looks like a pill, really. It's kind of an oblong thing. And it's sometimes used to make yogurt. We were interested in whether if you fed mice with this

for a number of weeks, whether it would alter their behavioral state. Meaning if you fed these mice a bunch of this bacteria, would they become very different mice? Yeah. Different mice, you mean like different mice, fatter mice or something? No, no, no, no.

Would they change their personalities? This is like a profound change. Because of a bacteria in their stomach? Yeah. Not in their brain. No. Just in their tummies. Just in their tummy. That's insane.

That's not gonna work. But let me tell you what he did. Right. He had two groups of mice. One of them got pelacidobacillus. The others, they got just normal mouse food. Yeah, we fed them a broth just as a control. So it didn't have any bacteria.

Then we looked at how they responded to a mild water stress and What we found was then was what it's that mean sorry well It's water. It's water at room temperature. It's basically what he did is he took these two groups of mice the Bacterium mice and the no bacterium mice and then he would drop them into a bowl of water. And on all rodents they're very good swimmers but they just don't like water. Oh. And what he was looking for was any difference between the two groups in terms of how they dealt with

this water situation. Like if one group squeaked more than the other or something. Whatever you mean. No you just keep an open mind and you wait and see what's going to happen. Fine. So here we go Starting with the first group the normal ones he dropped them in and as you'd expect the trine escape the trine escape Anytime them to see how long they keep at it, okay, and one minute passes this swim this swim to the edge and all around looking for an escape two minutes pass Three minutes pass. But, about four minutes in, he says the mice start to get worn down.

And then they decide at this point, there's no point I'm giving up. What, which means what? The ordinary mice just go to a dead mouse float. Yeah, dead mouse floats, you know, they just give up. They don't drown. No, no, no. They just sit there and think,

I will wait in this out until it's over. Exactly. It's been coined behavioral despair. I can't do this anymore. That is how a normal mouse reacts to being tossed into water. It struggles for about four minutes. It gives up and then sinks into despair. For the second group, this is the group

that eats the bacteria. Yeah, you just also dropped them in the water? Yeah, yeah, yeah. Here you go. At first, he said they were just like the first group. They were swimming around frantically for one minute, two minutes, three minutes. But then at the four minute mark when the first group of mice had given up, these mice, they kept going.

They kept looking for an outpashed four minutes, to five minutes, six minutes. So they're not despairing? Exactly. And they might have kept going on and on and on, but he then plucked them out of the water after six minutes. The thing that's kind of strange is like, you know, worrying and scurrying about and panicking. Like that all seems like what it is to be a mouse, and you're saying that a bacteria

in the gut can change that. Yeah. Wait a second, Soren. Okay, fine, there seems to be a difference between these two groups, but how do you know? How does John know that the bacteria had anything to do with it? Well, he didn't just stare at the mice, he looked at their mouse chemistry. By looking at the stress hormones,

and what he found is that in the first group, the mice that quit and dispaired, we got about a hundredfold increase in carcass-drawn levels. That's the hormonal version of, ah! Exactly. And in that first group, when he dropped them in the water,

their blood flooded with this one. Which initially, you know, it's not a bad thing, because a mouse has to act, but all-out panic isn't great for a little mouse, and after a couple of minutes of hormone coursing through the veins, the mouse just, you know, burns out and shuts down. But in the second group of mice, now these are the mice that eat the bacteria. We found that in the mice fed the lactobacillus,

they, well first of all, they had half as much of that stress hormone. Half. And they had another chemical suddenly in the mix. We found very, very distinct changes in the receptors for GABA in a variety of brain regions. GABA? GABA. What's GABA? Well, he says you can think of it as the opposite of a stress hormone. It basically is there to shut down the brain, stop things, inhibit, make us more relaxed, chill down. And he thinks what's happening is that in these mice that eat the bacteria, they hit the water.

The stress hormones come online, but before things get too intense, incomes gaba and gaba just goes. And as a result, these mice, they're chilled out, they're relaxed, they're not afraid. They never panic, they never burn out, and they never fall into despair. They behave like as if they were on valium. So somehow the mice, the gut bacteria of the mice are sending value to the brain. Is that what he's saying? That's what he's saying, yeah.

But he hasn't said anything about bacteria yet. It's a long distance. Well, let me, wait. Let me hear your brain up here. Look, John told me that if you look inside a mouse's body, you will find a giant nerve. The vagus nerve that runs between the gus and the brain. Oh, mean like a phone line? Exactly.

And he thought, well, maybe they chemically tickle one end of the line, send a shhhhh signal up to the brain, which then makes the GABA. Now, in order to prove this, he thought, it's not just cut the line. Basically, sever the vagus nerve. Oh, because then, if the bacteria are the ones doing it, if he cuts the phone line, they won't be able to do it anymore, and then the mice should go back to normal. Exactly. So, in collaboration with my colleagues in McMaster in Ontario, he got some mice.

We fed them the bacteria again. But this time before throwing them into the pool, he cut the nerve. And? We found that all of the changes that we had seen, the swimming forever, the not giving up, and the neurochemical changes in the brain. The GABA shh making them so calm, were completely absent. You cut out the highway MME, the communication, the brainy changes, stop, totally, totally huh when they cut the nerve the mice went back to being quitters yep you have to be convinced okay I'm convinced but so here's my

question though this is a mouse we're talking about this is just a mouse does us have anything to say about us I mean is there any connection to make? Well, I asked Carl that question. There was one study that, where was it? Oh, oh, you know what? So this was a clinical trial actually done in France last year. That's Jonah Lehrer, who regularly reports about things neurological for us and others. And he knew about the study too.

Yeah, so they fed people just massive dose of probiotics. Is it probiotic mean like the good ones versus the bad ones? Yeah, probiotics are the good gut bacteria. They're in yogurt and things like that. So these guys in France, they gave these people packets, like sugar sized packets of powder. And inside the packets, there are two different kinds of bugs. I don't know, Kto Basilis, Helveticus,

and Pifrobacterium, longum. It's true, my Dr. Basilis Helveticus and Bifurobacterium longum. Two of my favorites. Yeah, well, you should like them because they gave them to people and they showed a fairly dramatic reduction in their basal anxiety levels. They became less stressful and had less anxiety. Because when they took them to high diving boards and threw them off and sent a screen out of their, how do you test these things? I see the Hopkins symptom checklist.

I see the Hopkins. Basically, they did a little survey and asked questions. How distressed do you feel? They took levels of stress hormone. And the 24-hour urinary free cortisol. So they had some quantitative measures and people who took those probiotics said they felt less angry, less anxious, and less depressed. Wow.

So the gut bugs have us on a chain too. Yeah, because we have, you know, one thing to remember is like, you know, our mood, a lot of the way our mood is set is through serotonin. That's like when they do antidepressant drugs, it's the serotonin re-uptake something. Yeah, so you're controlling them out of serotonin that's going in and out of your neurons.

Right, you have very little serotonin in your brain, but it makes a huge difference. You have a huge supply of serotonin in your gut. 80% of all the serotonin in your body is in your gut. Really? Yeah, and the bacteria can be feeding on that stuff, and it could be that you know, they- You have an oil well of happiness in your gut, and if you get the right pump, you could feel happy more of the times. One possibility.

So, Chad, when you and I are sitting around feeling all stressed and anxious, or if we're just happy and gay in the old tense, of course. Now we know this mood is shadowed, influenced, and shaped by the bacteria you have in your intestine. The kinds of studies that show this effect, they've all happened in the past couple years, and that's it, period.

But there's this judge review, it was in the proceedings of the National Academy of Sciences. It was just kind of commenting on a couple of these studies and saying like, hmm, let's think about which bacteria we should focus on for psychological treatments. Let's think about how we can treat people psychological disorders with bacteria this way. Let's just think about it. This is in the proceedings of the National Academy of the Sciences.

They're talking about treating psychological disorders with yogurt. Yeah, medicinal yogurt in the future. But medicinal as in prozac. Sure. Medicinal as in whatever they give to people with schizophrenia. Well, I don't know.

I mean, who knows what'll work and what won't work. It's just, but it's something that people are saying, like, we need to look into this. There's something for me a little poetic about the fact that a lot of our moods come from the same organ that produces. I mean, I haven't put my finger on what's poetic about that, but it just, I it's right, right, right, right, right, right.

It does make a little bit more sense when you step back and think about this from the perspective of evolution. That, you know, our biggest decisions way back when, or what to eat, is this going to kill me and make me sick, is this food spoiled. So it makes sense that the part of the body which can detect that is also intimately connected with decision-making systems that have to do with this going to make me happy or this is I should fear this and not eat this. So as I'd landish as it seems that you know the self is connected with the part of the engineering logic to it. Special thanks to Carl Zimmer, his latest book is called Science Inc. It's a description

of tattoos that people get on the scientific themes and you can see them on their arms, their legs, thighs, and embarrassing places. Okay, ready. Hey, I'm Chad Abumrod. I'm Robert Krolyut. This is Radio Lab, and this whole hour we have been talking about... good. Guts. In the last section we talked about bacteria and the armies of them that are in your gut. Yeah, the problem is that they're a little hard to picture, kind of abstract.

Why don't we finish with a story that makes the whole issue real and much more concrete. This is the tale of a troubled relationship between a man and his on again off again gut. Yeah. Hello. Hello. Man's name is John Reiner. He's a writer, lives here in New York. So one day you are eating your way through your life as you usually do and then things take

an odd turn. Yeah. How did it begin? It began with the surprise. I was at home and I was about to go make myself a tuna fish sandwich. John thought, let me go to the bathroom first, get that out of the way.

So we sit down on the pot to do his business. And I felt a funny twinge in my gut. Now, John has had gut pain before. I suffer from something called Crohn's disease, which is a gastrointestinal condition, but I had gone through a period of about a year's remission, excellent health. And so when this pain came on, John figured, no big deal. It seemed to come out of nowhere and I thought, it'll go away out of nowhere. Like usual.

But it didn't. Within about, you know, a minute. What was a small twinge, all of a sudden, felt like a knife into my gut. Before long, I'm on my living room floor, flat on my back, and I can't move. John calls an ambulance, they rush him to the hospital, and when they get there, the doctors take one look and tell him, you're in testin's reclog and now they burst. And it's now spreading bacteria throughout your system. Basically, you're on the verge of having sepsis, meaning you could die.

So you need emergency surgery, but they also told him that I shouldn't recover. And when he came out of the OR, look like he would. But the doctor said, let's play it safe. Stay here for a week. We'll feed you through an IV. And give your gut a break. So I'm on an IV for a couple of days. And I've been on nothing by mouth in the hospital numerous times before. But always for four to five days. And after four or five days, John says what normally happens is that you'll start to feel hungry again.

And that's a great time. That means that your gut is healing and it's ready for food. But this time, that didn't happen. In fact, he says he got sicker. Nausea, vomiting, chills, fever spike. So the doctors take more pictures of Johns Insides and they notice something weird. In the area where I had the tear in my intestine, there's now a fist chilla, which is a hole. Normally, this is something you could sew right back up. The doctors tell them, in your case,

no. The tissue around the area of the tear is so compromised that you can't withstand another surgery right now. Plus, you've got high level of infection again. You're no candidate for surgery. Our only solution, they tell them, is to let your gut heal on its own. But in order to do that, we've got to shut it down. Yes.

Basically numb it with anesthesia. So my gut was in an induced coma. Nothing would pass through it. There would be no activity. Which meant the doctors told them, obviously, no eating. Instead... We're going to put you on a food pump. And the food pump is a mechanical pump about the size and the weight of two bricks carrying the backpack.

And the pump in the backpack is attached to this big bag. Big bladder, the big 3,000-millimeter bag of TPN is the medical name for the nutrients. What does that say for? Total parentarral nutrition. And the stream runs out of the pump through the tube into my arm. You were going to be given essentially an outdoor stomach. That's right. And this is where our story really begins.

So John goes home with his new exo-stomach. He can eat, but every day around meal time he says, he would turn on the food pump. This is actually what it sounds like. So I'd start my feeding at 4 o'clock. Pump would start at sit-on, the love seat for a while. My kids would come home from school. My wife would come home from teaching. And then the real food would come into the apartment.

Sometimes neighbors brought food over, sometimes John's wife would cook. Regardless, I was always sitting on the loves to eat in our living room with the food, pomf, or a like a dishwasher. While just a few feet away, his family would sit at the table, eating fabulous food. Night after night. This happens. And it's making me absolutely crazy. And he says, after about a week of this, and then two weeks,

and then three weeks of just sitting there, night after night watching his family eat dinner without him, he says he would start to drift off. And get lost in these really vivid daydreams of meals that he'd eaten in the past. One of the first memories I have is going to Katz's for the first time. Katz is a famous Jewish jelly in Manhattan. And standing there at the counter, where the counterman cuts the pastrami and puts it on the plate. It cuts it out of the hot cooker and it's on a fork and he hands it to you and you take a taste.

He says in that particular instance when he took a bite, that first bite of the pastrami sandwich, it was like, pow! He said it was the first time in his life where he suddenly he was like, oh my god, I'm Jewish. I am Jewish. She's to my people. That was the first time he felt that? It was. It was. And after about a month of no food at all, and these vivid daydreams about food,

something weird happened. John got hungry, like actually hungry, which really doesn't make much sense because hunger signals normally travel from the gut up to the brain and his gut was numb. But he says he really started to feel hungry. It was, you know, I think it was an existential hunger. And he got really bad. For example, my wife's terrific cook and one night she made a little treat for the kids Many burgers and french fries and our small apartment smelled like the kitchen of a white castle so

My wife brought out this big plate of Sliders and a pyramid and the kids were knocking down the pyramid and throwing the back and I Couldn't take it anymore So I snuck out of the living room while they were preoccupied. I went into our kitchen and there were some fries on the stove top. And I put my hand on the fries and I brought them up to my mouth. And I was expecting salt and oil. Fatty goodness.

Fatty goodness and the texture of crunchiness and all that I'm tasting it now and I put it on my tongue and I've got nothing Nothing really and I'm rolling it around an option. You can't even feel it on your tongue Feels even the salt. It's like when you go to the dentist and you've got no vacay and really and my tongue is numb and I'm roll So I start your tongue is out of practice.'m so sorry, you're telling us how to practice. I couldn't figure out what was going on, and then I brought up a knife.

And John claims that when he looked at the reflection of his tongue in this metal knife, I see that my tongue is as flat and smooth as this Formica tabletop I've got my hand on in these two. Oh, so you don't have the little brisket. No bristles. Right, and I realize I haven't used it in so long that my taste buds have evaporated.

They're gone. And at the moment that that happens, my oldest son, Teddy, who was nine at the time, comes in and he says, Dad, you're not supposed to eat. I said to him, I wasn't eating. I wasn't eating. That's like you switch places almost. And he looked at me with the most scornful, disgusted, just ashamed expression,

and I was completely humiliated. I normally fail this in either sheam flood. Right, I failed as a father as well. As the week straggdon and John didn't get any better, he actually started to take that thought seriously. Like maybe he really was failing at being a dad. I'm a stay at home dad and as a result I'm the shopper and the cooker and the food planner and the provider for us and I was out of commission

three years out of work with no gut Meanwhile, I can't stop thinking about food I'm remembering food that I ate 20 years ago like I had that afternoon and I'm online Looking up menus from restaurants that I've gone to really yeah and and looking up from restaurants that I've gone to. Yeah, and looking up recipes, you know, for dishes that I've made. In the obsession grew and grew until one night he says his neighbor, Marcia.

I decided to cook for us one night when I wasn't eating, and she brought down a chocolate butt cake for my wife and kids to eat. Wax it right past John on the way to the kitchen. And I could smell this thing. I could smell the rum. I could smell the eggs And I could smell this thing, I could smell the rum, I could smell the eggs, I could smell the flour, I could smell everything.

So again, he sneaks into the kitchen. And I lower my nose down to this butt cake and I'm smelling it and I'm sniffing it and I'm inhaling this thing like an anteater. And that's not enough in my state. So I plunged my hands into the chocolate cake. You what? I plunged my hands into the chocolate cake.

You'd order to get one with the goo or what? Yeah, order to get some sensation of connection with food. Did you think what's happening to me or did you think over to me? At the moment my fingers were in this cake? I felt I'm in heaven. I've reconnected with the living. I have food, if not in me, at least on me. And at the moment where a lot of I'm experiencing most pleasure, my wife comes into the kitchen. When I went in to get the kids more food, I found him. This of course is John's wife, Susan. With his hands in the cake,

just trying to touch the crumbs. And he looks so guilty. And I was also like, what are you doing? What are you doing? Like somebody going through an underwear drawer. It was very wrong. And I have no explanation. I mean, I can say, I need to do this.

You have no idea how wonderful this is. Please give me some time alone with my fun cake. You know. It was just, it was this bizarrely funny, but deeply sad perverse moment. Yeah. I suppose it was the first crack in my, in my bubbled attempt to pretend things were normal.

You know, I realized how bad things had gotten. And after that, she says, things only got worse. It just became, there was never anything to be happy about. He wasn't able to eat, he wasn't sure what the prognosis was, he wasn't sure if he was going to need a second surgery. It was just all bad. She says John became really depressed. And he became very difficult to even not even to cheer up, but just to say, well let's just not talk about it for now. You know, he was constantly expressing his unhappiness. Was that the thing? It was just the, it was dark all the time.

Very dark. It just became very hard to face. So, she left. Well, I had spring break and my kids had spring break. So Susan took the kids to her parents' place in Indiana for a week. I needed, I needed to take a break. Not for good. Maybe the kind of break that means, I'm not really sure what our future looks like.

I don't know how we're gonna do this. And I can't really figure that out while I'm with you. So I was alone, not entirely. While I was on the food pump, and not doing well, but after a few days of moping around the house, John gets an idea. What I need to get myself out of this is I need to return to a place of sanctuary for me.

There was a restaurant, not far from your studio here, called Chanturrell. It's a French restaurant. And it was one of these very expensive capital letter restaurants that my wife and I had always planned to go to if we had a special occasion. For years I walked past this restaurant and I would look in the window before getting onto the subway and I would see the plates of scallops coming out and the wines to it pouring red wine and the handwritten menus on the tables and things like that. So I thought, if I can get to Shantarral and if I can look through the window, then I

can heal myself. I'll have a reason to hope. So I got on the subway and it was past four o'clock and I was supposed to be home starting up the pump and feeding. And I got off the subway and I walked over to Chantarelle. I was kind of a little dizzy and delirious. And I get to the window. And the dining room is empty.

There's dust on the floor. The wall panels have been stripped. The tables are bare. It's empty. It's a cave. Sometime in the intervening months or the preceding months rather, Chantarell is closed, and I didn't know that. You kill him, he with a story. And I think to myself, you've reached the end of the line, this is it, there's nowhere else to go.

And I walk towards the river, and I know that people throw themselves in when they do this. And it never made sense to me before. I wasn't ever ready to end things. Were you really? Because I was... Were you having suicidal thoughts? I was having really depressed thoughts. And I don't know that I would have thrown myself in, but it was the first time I was standing at the edge thinking about it, thinking about, this is how these things happen. So I got to the river, and I blacked out, collapsed on sidewalk, and I woke up and it was dark.

I'd scraped my chin and my elbows were bruised and I'd taken a hard fall. I'd scrape my chin and my elbows were bruised and I'd take a hard fall. And I got up and I started to walk around. I was on this buckled old sidewalk and I looked around and there are these federal era houses. And there was a grill, a gas grill in one of the backyards that was going. Somebody was cooking dinner. And I could smell it. I could smell the smoke coming off the grill. And I could smell it with pork chops.

And I was so hilarious. And so happy to be smelling food that I took it upon myself to finish cooking this guy's meal. So, wait, what? So, I, that's so eerie. I lifted up the lid. I lifted up the lid and it looked like to me, you know, one side of the pork chops were cooked and they were ready to be flipped. So I flipped them. And, um, I was so far gone, and I thought, okay, well, four more minutes and these babies are going to be ready to go. And, and I didn't have a watch, so I started counting down four minutes in my head

because I was gonna get this stuff perfect. And all of a sudden, the back door of this townhouse opens up and a guy walks out with an apron on and a cocktail in one hand and a seasoned shaker in the other and he looks at me. And I look very borderline. I mean, I'm rail thin, I've got it, you know, I'm cut up from having fallen on the sidewalk, I've got, you know, I'm crazy expression in my eyes. I haven't shaved in, you know, a week.

I look really very unsavory. So he sees me and I have no way of explaining myself other than to say they're just about done. And I hand him the tools and I turn around and I walk away before he has the chance to call the police or anything like that. How many years ago was this? This was now three years ago. And what do you take away from that? Was that some kind of turning point where you walk away from the grill and you're ready to fight the good fighter or what? That only happens in the movies and fairytales, but actually happened was I got sick again. I had another infection, more bacteria, and I had to go

back to the hospital. And when I went back to the hospital this time, they said, okay, we can't even do the food pump anymore, because you keep getting these infections, and if the bacteria spreads to your bloodstream through the food pump, then you'll be gone. And we can't operate on you, because you won't survive the surgery. So all we have left is to try eating. The only thing that's left

is to go back to food because you can't ingest it intravenously. We're afraid of infection and we can't repair your gut surgically. So the only way you can keep yourself alive is to try to use your gut again. So they start you on a round of, I don't know, baby food, Gerberus? I did start on the traditional applesauce and jello and pudding, soft and easily digested foods. And John says, it worked. His body was able to take the food. But I couldn't taste anything.

And it continued that way for another couple of months. And did the food ever taste like food again? Well, I was at the radiologists. This is nuts, the scene I was expecting. Well, you know, I have a little ritual with this particular radiologist. He's on the east side and whenever I get tests there, when I'm done with the tests, I'm able to eat again. And again, this is when you do test prep, you're going about 24 hours without eating.

So, you know, the thought of food becomes a celebration that you're going to have, right? So there's a diner on 3rd Avenue in 84th Street, a 5th Street that I always go to. And I get to save me every time I sit at the counter and I get a fried egg and bacon sandwich on whole wheat toast. So I went there and I got the last seat of the counter and I ordered my usual and I chew into it and I realized that I've got sort of embryonic flavors going on. I've got the sort of the start of the sensation of tasting and the start of flavors in my mouth and I could feel that great combination of the fried egg

congealing with the crunchy bacon and the crunchy toast. And I do the same, you know, I've got a knife about a knife and I do the same mirror knife examination at the counter. And I can see that where before it was shiny and smooth as a porpoise, I've got little bristles. I've got little bumps on my tongue, and I can taste this fantastic $3 sandwich. Do you kiss the lady sitting next to you?

Well, I turn to the guy sitting next to me, and I tell him, this is the best damn thing I've ever eaten. And in classic New York diner fashion, he looks at me, he looks up from his kindling, he looks at me and he says, you should try the meatloaf. He's like, he's like, he's like, and I think, you know this is it, I'm back baby, I'm back. Radio Lab was created by Jad Abberrod

and is edited by Soren Wheeler. Lulu Miller and Lackith Nasser are our co-hosts. Suzy Lektenberg is our executive producer. Dylan Keve is our director of sound design. Our staff includes Simon Adler, Jeremy Bloom, Becca Bressler, Rachel Q. Sik, Aketty Foster Keys, W. Harry Fortuna, David Gabel, Maria Pasco Tierra, Sindu Nene Sanban Dam, Matt Kielte, Annie McEwen, Alex Nissen, Sour Cari, and a Rascwed Pass, Sarah Sanbach, Ariana Watt, Pat Walters, and Mali Webster, with help from Andrew Vinales. Our fact checkers are Diane Kelly, Emily Krieger, and Natalie Middleton.

Hi, this is Tamara from the Pasadena, California. Leadership Support for Radio Lab Science Programming is provided by the Gordon and Betty Moore Foundation, Science Sandbox, a FIM and Foundation initiative, and the John Templeton Foundation. Dundational Support for Radio Lab was provided by the Alfred P. Sloan Foundation. was provided by the Alfred P. Sloan Foundation.