The Gut-Brain Connection, with Emeran Mayer

What is the brain-gut connection? Surprisingly, it was never really identified as the brain-gut connection. All these systems in the gut are interconnected with each other. So, the gut is, is, is like a brain. Within the gut, we have the immune system, and the microbes also live in the gut, and the nervous system in the gut. They all communicate with each other all the time.

Why haven't we evolved to do without microbes in our gut? Every organism today, from the cockroach to the butterfly to humans, has a microbiome. A gut microbiome. Whoa. We think that, like, we're in charge. Yeah. But we're an Uber ride. That's what we are.

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This is Star Talk, special edition, which means I got Gary O'Reilly. Gary. Hey Neil, how you doing, man? I'm good. Chuck, always good to have you, man. Good to be here. Of course. All right. Today, yeah, I'm, I'm checking out this subject. I love it. Okay. All right. The gut-brain connection. Ah, some people's brains are gut. Oh, we went philosophical straight away. So, Gary, tell us why. What's going on in this episode?

Okay, so we've had everybody for our lives tell us they've had a gut feeling about something. Gut feeling. Yeah. And then we've seen people under stress dive. They don't say, "I have a brain feeling." No, this is exactly it. And we've seen people who are under stress dive into the fridge. We've seen people who are depressed not want to eat at all. And then we kind of work out that our guts are not standalone systems within our body, right? That there is actually a direct gut-brain connection. So that gut feeling may actually be a fact, not a fictional imagination of somebody. Now, imagine, just imagine this, that every emotion you have has a mirror image within your gut. Oh, that makes sense. Right? Now, they call it "hangry," don't they? Don't they just? I'm hangry. I'm hangry. And here, spoiler pun coming. Uh, that is obviously our food for thought. And now it's our time for an expert. And now I'm hungry. There you go. I see what you did there.

Okay, we have with us here in New York City, uh, visiting us at the Hayden Planetarium, right here in my office, a gentleman based at UCLA. We have Emran Ohyer. Yes, I think I said your name correctly. You're a medical doctor at UCLA. You're a gastroenterologist, which is a lot of syllables to say you're a gut man. I think we like that. But am I correct? A Scrabble winner. You're also a neuroscientist. You hardly ever see those two in the same phrase because your brain and the gut. Well, more increasingly, you do now. Maybe. So, all right. And you're also an author. And the books I got them here. Very, very simple. It's just Mind and Gut. Mind-Gut Connection. Mind-Gut Connection. That was in 2016 with HarperCollins. And then Mind, Gut, and you added a word, Immune Connection. Immune Connection. So the mind-gut is taking over the, the body here. Yeah. All right. We'll see where that can take us. And so my notes here say you're also a documentary filmmaker. What, what, what's up with that?

Yeah, I almost, um, didn't go into medical school because I was fortunate. Um, a retired businessman invited me several times to accompany him as a sound assistant to places in New Guinea and, um, on the Orinoco River to the Yanomami, um, Indians. And very formative experiences. And wow, the nice thing is I can now reconnect back. I mean, I was just a, you know, first-year medical student, had no idea about any, any of the things I know today. These people that we visited and, and, and lived with, the Yanomami are a very interesting group of people that have the, the healthiest microbiome on the planet. So, really found out that, and, and how they poop three times a day. I was going to, well, that's what I was, that's where I was getting. I was like, how exactly did we determine that that they have the healthiest body? Are you digging into their poop in the forest?

So there was a scientist, Gloria Dominguez, married to a very famous gastroenterologist and researcher, and they had the interest in, in studying the microbes of, um, of peoples around the world with what they call the vanishing microbe. You know, we're losing microbes. Or so they went to the Yanomami and did the most elaborate analysis. Didn't do it there, obviously. Took the samples and, um, it turned out that this microbial system that these people had is the most diverse and richest of anybody. They must have thought you were crazy. Can, can I have some of your poop for my lab back? I don't know. I know some places in New York where you get charged extra for that.

So, just to finish your, your resume here. So you're a professor in the departments of medicine, physiology, and psychiatry. So that's evidence of your, your breadth and what you brought together for your studies, and it's, and it's guided me. So my career has led me down this path, at starting in the gut and then always having an interest in the brain and the nervous system, and at some point, they said it was necessary to, you know, connect to these other departments. And that's at the David Geffen School of Medicine at UCLA. Let's just get this started. Mhm.

What is the brain-gut connection? And if I understand the timeline correctly, nobody was really talking about this until your books came out. Oh, really? So, so you wrote the book. You're a pioneer on the brain connection. It was, it was a surprise to me because I've struggled in my professional career for literally decades to get this concept of brain-gut connections accepted as a major factor, not just as an epiphenomenon, but as a major disease factor in, like, inflammatory bowel disease and irritable bowel syndrome. Many of these, what we call functional gastrointestinal, the IBS, I guess. You hear it all the time now. Yeah. On TV commercials. And, um, so it was like, was kind of amazing, the enthusiasm that gradually developed after the book. Not the first year, was not really popular the first year, but then gradually it picked up. And now, if you go on, on, go online, I mean, every second word is "gut health" and "brain." You hear about it all the time now, in, in more of a cursory fashion, you know, there's not a lot of in-depth talk about it. But what is your gut?

Well, I would say the gut, I would say is the, after the brain, the most complex organ we have in the body. Okay. It's not just a digest. It's a tube from the, you know, from the mouth to to the anus. And for a long time, digestion and, uh, absorption and storage of waste has been sort of the main focus of, of, of interest. In the meantime, we know that, you know, 70% of our immune system is embedded in the gut. Big portion of our hormonal system, endocrine system, is embedded in the gut. There's a, a separate nervous system in the gut, which called been the "little brain." Mike Gerson here from New York, Columbia, sort of been a pioneer in, in, uh, describing and popularizing that concept. Wait, wait. So some people literally have their brain in their ass. Is this what you're saying?

But if you, yes, I know we probably don't know the same person, but we know they're like that. Yeah. Yeah. But, but to sort of ramp up this the answer, all these systems in the gut are interconnected with each other. Okay. So the gut is, is, is like a brain. So who's talking to who? Is the brain talking to the gut, or is the gut talking to the brain? No. First, within the gut, we have the immune system and the, um, you know, the microbes also live in the gut, and the nervous system in the gut. They all communicate with each other all the time. So you don't know it. You know, right now, if, if I could look inside of you with the right lens, you know, I would see all these things interacting and talking to each other. Then you add the brain to it. Um, and it's the same thing. There's a, a bidirectional communication going on 24/7, even when you sleep. Always. Anything that happens at the brain level, said earlier, has a mirror image in the gut, which we don't see. You see it on your face. So if you're angry, I can see it on your face. We can see that the gut contracting when you're angry, but also a lot of things that go on in, in, in the gut generate emotional feelings or, um, most of it, 95%, doesn't become conscious. So that, that's the thing about the.

So we have receptors and transmitters. I can say it, but what are they? How are they activated? How are they working? And I'm obviously not emailing each other. But, and just to clarify, when you said it's not conscious, it means, if I understand that, it means you will have a feeling and you won't know why, but you'll then act on that feeling. And if it's your mind-gut connection controlling it, it means you have behavior that's being commanded to you by microbes that you need a microscope to see. Yeah. But what I want to say for a lot of people, they're not aware of this, you know, they're very oblivious to the, to their body. They just have urges, right? Yeah. Yeah. But, but like a sensation that, that everybody knows is, uh, satiation, hunger, and satiation. Absolutely. So these are the most basic gut feelings that people have. And it's so funny you say that. When I was younger, my mother used to say, I would eat and then I'd say, "I'm still hungry." And she would say, "Just wait 10 minutes, and your stomach will talk to your brain and let it know that you're not hungry. We'll catch up with the." Yeah, your brain will catch up with your stomach. And I don't think, I don't know where she got that from, but damn if that's not the case. Yeah. A lot of people have lost that, that mechanism, you know, like a big part about obesity is that, that, that signal that comes from the gut, this GLP-1, this molecule that everybody talks about, everybody talks about, is produced in cells in the gut and goes to your hypothalamus in in your brain and tells your brain to stop eating because you're full. A lot of people have lost that, that mechanism, that feedback. Um, why that is, but it's not clear. But so what do you now do with mega doses of this hormone, right? 100 times higher than what your gut produces? These are the GLP-1 injections that everybody sees on TV now, right? So that, that gives you that sensation. But you know, in a, in a GLP-1, excuse me, got a pharmacist sitting here among us. We can't help it. It's on every TV channel. That's true. And by the way, how do you think I lost 20 pounds?

So you're saying, so this, I didn't know this. So this chemical that we see advertised a 100 times a day. Yeah. Is that molecule but heightened to create this sensation that really your body should have been producing all along. Yeah. Uh, it does a lot of other things. We, we don't know many of them because now all of a sudden, you know, it seems to be effective in substance use disorders. People who take it find that their urge to drink. So people who have an alcohol abuse problem, they stop abusing alcohol. They're like, "Yeah, I just didn't want to drink or, you know." So, and, you know, it's, it's kind of ironic when I first came to LA as a, as a research student, I, I studied that, that that hormone, you know, and also its sibling called GIP, that, that there's another medication that has that. And at the time, we didn't know. We were just excited to find all these substances in the gut, but nobody had a clue what they do. It, it took really literally 35 years or 40 years before.

So, I know you got a bunch of questions here, but I want to establish something. How was this received when you emerged with this idea that your brain and your gut are connected in ways no one understood previously? Because, as I understand medical school, you study the brain, you study the brain, you study the gut, you study the gut, and there's a siloing of the body where we are just bits and pieces assembled into one thing. Absolutely. And the idea that there's a connection will require that somebody in that mix has interest in more than one aspect of human physiology. Yeah. And I, I would say, you know, I've had a long-standing interest in college on in psychology and, you know, read all the stuff Jungian stuff. And, uh, so I, I came into medical school already with this background in, you know, in, in brain science with a perspective. Yeah. Yeah. With the perspective. And I would actually say that the main reason I ended up in medical school, I, I thought I was going to go into psychiatry because I, but then spending a month in a psychiatry rotation convinced me, this is not what I want to do. Those people are okay. Never mind. Okay, I might do it today. I might do it today because psychiatry has moved on a lot. Really has. Yeah. But I had a very open-minded, um, a very charismatic, uh, mentor who really supported me in, you know, from the beginning. Yeah. So he was interested in isolating all these molecules like the GLP-1, not necessarily on the brain. And I said, "Can we combine this, you know, with, with the brain?" And he was very open-minded, um, unusual. But most of my colleagues either ignored it, didn't find that interesting, or then there were, like, in the IBS field, for example, there, there were, like, really entrenched interests of people that say, "IBS is a gut disorder. Right. Forget about the brain." You know. And which is so counterintuitive from the fact that when we're all kids, we learn that the hip bone is connected to. It's as simple as that. All the bones are connected to. Like you would think that it would be just, you know, the gut bone connected to the brain. It would make perfect sense, right? It's the first thing we learn when we learn anatomy, day one. So, but, but it goes further than that. I, I think, you know, med, Western medicine, very successful, obviously, in many aspects, but it is based on a reductionistic view of the body, not an interconnected, not a systems biological. And it's gradually changing from the. There's a couple of developments, like there's an entity now called functional medicine, non-scientific entity, but also in science, there's more and more scientists that think in system interconnectivity between the systems. So it, it'll, it will take another 10 years, I think, and then it will, it will change. I mean, they'll catch up with you. How about that?

We spoke about GLP-1, but you've got cortisol and serotonin. Yes. The stress. I suppose we love eating. We have an experience when we eat certain foods that maybe you'll tell me yes or no with serotonin being released in the gut or dopamine. And then the cult, like I say, you're diving into the fridge because you're under stress, and you're going for the sugars or the fats or whatever it is. I mean, how long did it take us to work all of that out? And, and, and we've got this image of the person who just broke up. Yeah. With their, their loved one, a gallon of ice cream, watching a a sad movie, crying. What's up with that? That's what sad movies do. The gut likes Hogenas ice cream or any other ice cream. Yeah.

So, so, so there's some very smart people that worked in this area. So, surprisingly, it was never really identified as the brain-gut connection. You know, they always talked about appetite and, uh, stress and substance use disorders, but, but it never really became sort of an essential part of. But, but that's really how it started. You know, we knew these things for, for quite some time. Very good scientific studies support it, but, but it's not really become a specialty. You know, it's because of this dominant paradigm, I think. It's not so. Going back to Chuck's, uh, insight into anatomy, that the kneebone is connected to several other things, connected to the brain bone. So, how, how is the gut connected? A, to the autonomic system and then the vagus nerve, spelled with an A, not an E, and what does the vagus nerve do? Because we've heard about it. I couldn't tell you, actually, where it is in the body, but it's right. Yeah. The vagus nerve. Okay. Above your clavicle, where your neck is, and it runs down. Why are you telling me this and not the, the good doctor? All right, doc. Tell us where, where's the vagus nerve? Where you said exactly?

Yeah. So, the vagus nerve, first of all, it's a, it's a bidirectional pathway. You know, it's like a bidirectional freeway. Okay. Most of the traffic goes from the gut to the brain, to the brainstem, and then to higher emotional centers, and 10% goes the other way. Um, so, for example, to stimulate your the acid production in your stomach, that's a vagal phenomenon. That's why people used to do, cut the vagus nerve for ulcer disease. This was a dominant. Wow. Wow. Which, which is amazing when you think about this is only like 30 years ago that we have absolutely no understanding. Cutting off your foot because you have an ingrown toenail. Exactly. That's insane. Wait. So where, where on your body is the vagus nerve? It goes down from your brainstem. Okay. Down your neck. Um, just like that sounds like just what Chuck Knight said. And then, did Chuck say that 90 seconds ago? Just tells you not. Okay. So, but, but what's important is to realize, so the vagus nerve has branches to all your organs. It monitors every organ function, seven, 24/7. The ones to the gut have received a lot of attention because we were always wondering, why is 90% of the traffic going from the gut to the brain? There's not that much happening that the brain needs to know. So now we know there's all these receptors on the vagus nerve for serotonin, for, for these, for GLP-1, for the GIP. So disproportionate, what we call afferent, or sensory signal to the brain, is related to this complexity that goes on in, and, and, in, in the gut, and the signals it gets from the microbes. It's a processing hub. Yeah. Yeah.

So I'm still confused. How does any of that relate to your immune system? So the immune system, I told you, more than 70% is located in the gut. Sandwiched between the layers, seven, zero, 70 zero. Wow. Sandwiched between the layers of the gut and in very close communication to the microbes in the gut. Microns away, you know. So how nature could engineer something like that. That's potentially deadly influence of micro. So a micron is a millionth of an inch. I mean, a millionth of a, of a meter, I guess. Of a meter. Right. So that would be a thousandth of a millimeter. Yeah. Would be a micron. Yeah. Yeah. So the immune system is very close to the vagus. Some of these sensor nerves go into the, into this immune system in the gut, and they pick up signals that, that the immune system produces, like cytokines, for example. Best studied. And that has all kinds of effects on your behavior, you know, like cytokines, um, fatigue, chronic pain. Some, oh, yeah. I, well, I got to come at so pause, then what is the urge that people have to, what do you do the, when they clean out the colon? Uh, a cleanse. Cleanse. This is urge to get it all out. Oh, I'm going to, I can answer that for a doctor. And or people prepping for a colonoscopy, they're cleaning everything out. So all these microbes that set up shop to communicate with the brain, they just flow out your body, just for the benefit of one of your colleagues to look up your butt. Okay. And so are we destroying this hard-earned ed microbiome every time we get ready?

Um, oh, Chuck had an answer. What's your answer, Dr. Chuck? Okay, so here's my answer. Uh, for the cleanse, that's. So that's the first human. But yeah. No, no, I'm saying the actual cleanse itself. I mean, I know it's supposed to get rid of your stuff. That was a joke. Oh, I'm sorry. Wasn't that a good joke? Oh, I thought you were saying it like. Okay, never mind. You said it's. No, you said no. You said no. It's human. See, we missed the. No, cuz I would have laughed at that cuz that's funny. Excuse me. I'm sorry. I missed. But the colonoscopy, that's so that they can look at your intestinal lining, and the good stuff that's that you need is in the walls of your intestinal lining. So cleaning that out so they can look at it, you're not getting rid of. So. Okay. Yeah.

So two answers from my side. The first one, I would contradict what you said because. Oh, you think it's real. So. Well, you know, Ayurvedic medicine for thousands of years has propagated these, these, these colonic cleanses. All right. So what is the, what is the benefit? Let's, because everything I read says that the benefits are negligible at best. Okay. Unless, wait, that would be health benefits. But suppose you just feel better. Doesn't that count? I mean, you know, doesn't that, we're talking about how you feel better when I punch a puppy? Does that make it? I'm sorry. Did I say that out loud? Okay. Yes. Anyway, tell me, tell me why it's good before I get arrested.

So, so for a long time, this has been dominated or driven or motivated by this concept of cleansing. So, humans are obsessed with cleansing. You know, they, they spend a lot of money on, on cleansing. So, not just cleansing the colon, but a cleansing diet. And in not 19th century Europe, but in modern times. Yes. Cleansing. But it's become very popular again. Talking about your ancestors. I know. I need, I need to dig. Take a bath once a year and only if necessary. Yeah, but it's our birthday. You got to celebrate. Okay. So, so with, with microbiome science, um, there's a certain potential explanation why people have been doing this over thousands of years. Why? Well, because it reestablishes a, a balance within, you know, within your colonic microbiome. Okay. Has not been studied scientifically, but it's certainly you're saying it's feasible though. So even though it's not, even though we don't have empirical scientific peer-reviewed studies, it's a feasible concept that this could be the case. It is, it is conceivable. And it's, so the blueprint for your microbiome doesn't disappear with that. So you cleanse out the, the population, the blueprint is there, and it can re, the body can reconstruct the, the. Okay, so it's a jump start. Jump start. A jump start. All right, fine. I changed my mind on that. Stripping off a stripping off a layer of paint and then just it re, reevolves itself to bring a new layer of paint. It's nice and shiny.

So if our microbes are not important in our gut over evolution, we'd have got rid of them. It's like sleep. We are never more vulnerable than when we're asleep, right? Yet we've not evolved to do without sleep. Why haven't we evolved to do without microbes in our gut? What? How? How come this? Because they're the OGs. They're the original life forms on this planet. They've been here for 4 billion years. You know, three and a half billion. Can't get more OG than that. Sure. Three and a half billion people. Original gut, you know, nicely done. Thank you. But it's been the most successful evolutionary development because every organism today, from the cockroach to the butterfly to humans, has a microbiome, a gut microbiome. Wow. There, there's not a, a complex. So there, there's a number I calculated and it just freaks people out that if you go to your large intestine and take one centimeter slice through it, just one centimeter. One centimeter. That's 4/10ths of an inch for those who, for Americans. Americans. America. That's right. Don't bring any of that metric crap over here. Talking about America, boy. You better talk to me in inches. You know, talking about millimeters, centimeters. That 4/10ths of an inch lives and works more microbes than the total number of humans who have ever been born. Wow. So that we, we, we think that, like, we're in charge. Yeah. But we're just a darkened, anaerobic vessel of fecal matter for microbes. We're an Uber ride. That's what we are. We're an Uber ride for microscopic organisms. Microbes. Yeah.

I read something recently in a book by one of my favorite scientific authors, Antonio Damasio, um, on this comparison, the early life forms, you know, which, which had a lot of intelligence. I mean, these microbes on the planet must have a phenomenal amount of intelligence collected over three and a half billion years, but they couldn't do long division. So, yeah, but, but I mean, they don't have a mind, and obviously they can do, they, they can live in homeostasis with each other and with the world. Their main benefit is that they now can connect to our brains and can influence a much, a conscious entity. But what I mean, so they do have a mind. So if we've got the original gut microbes, the OGs, as we now like to refer to them, three and a half billion years, they've invented their own language. They've got, they've had to have an own their own alphabet of sorts. So how are they communicating with us from their little hidey-hole in the gut? You know, they have millions of genes compared to our, you know, meek number of 10,000s. In these genes is stored all this information, how to build these molecules, how to, how to use them. So their language is basically stored in, in, in their genome. So their own history of three and three. No, I was, I was about to swear before I got to the B billions and billions. Okay. So then when they settled, the first microbes settled in this floating tubes, uh, of the first, you know, marine animals, they interacted with these floating tubes, and there's something called lateral gene transfer, that they transferred some of these genes that they had about their language into these animals, and, you know, fast forward, that was the first version of the so-called the little brain of the gut, or the enteric nervous system. And then with animals developing heads, becoming polar organisms, some of the same information about language was transferred to the brain. What is a polar organism? Having a head and the opposite end, whatever that is. Okay. Okay. Yeah. So our language, our ability to think, comes, uses the same building blocks as the microbes developed over billions of years. I mean, that to me is one of the more fascinating ideas. Incredibly fascinating.

So seeing as how we have the gut-brain connection, seeing as how microbes have their way of communicating with us, is this the superhighway that is used for psychedelics? Because we're ingesting and yet everything's going off up here in the brain. Mh. But not so much down in the gut. So is there sort of exploration? There are a lot of things going on in the gut that we don't know yet. Like serotonin plays a big role, as, as, you know, with the, the psychedelic experiences, activating a particular serotonin receptor, the 5-HT2A receptor, which is in, in, in the brain. So these psychedelic experiences seem, many of them seem to be related to that receptor in, in the brain. Now, the same receptor is also in the gut and on microbes, and we don't know what effect, um, this actually has. But one, and it can't be an accident, right? It's not an accident. It's a co-evolutionary thing, right? Okay. So, is the, is the mind desperate to try and expand, and that's why it's so active to find something like these psychedelics and then just whiz them up to the brain? Yeah. I mean, humans have probably used psychedelics for a long, long time. A long, long time. And based on their experiences, initially by accident, that they ingested a mushroom, all of a sudden, sort of world is that the, sort of when you talk about in evolution, they just by accident eating a mushroom, is that sort of the beginning of a stoned ape theory of evolution? Phrase stoned ape. Yeah. Yeah. Okay. What is, what is the stoned ape? I mean, I've been to the zoo, but I've never seen him, you know, an ape. I would love, I would just love to sit there and watch a chimpanzee tripping his balls off. I would love that. But I haven't had the pleasure of seeing. Well, in out in the wild, I'm guessing they'll stumble across a mushroom, be curious, and eat it and go, "Whoa." So, isn't the basis of where Gary's coming from? Why do we have receptors for psychedelics at all, unless it was the purview of the microbiome that delighted in it? Yeah, that's a really interesting question. I, I, I can't really answer it. I can only say partially based on personal experience. I guess I can say this here, even though it's, you know, it's, it's, it's not, I'm not recommending for people. I am, I'm recommending for you to do it. All right. The, the good doctor here can't. I'm letting you know everybody should do psychedelics. I mean, I can't do it for legal, medical, legal reasons, and sue me, please. But do it. But the experience, you know, that you have, and everybody says this, it's, it's a universal human experience. It's not that one person gets this, this, this realization of the interconnectedness of yourself with the, with your environment, the planet, like you get a totally different paradigm. Oh, yes. So you, Chuck, you. Oh, god. Yes. You missed a few shows a few while back because you, you, I traveled to Costa Rica to do Ayahuasca for an entire week. Wow. And, uh, I will tell you that it changed my entire life. It changed my perspective on everything. Did you get funnier? Not at all. And, and, you know what? While I was in my one of my, uh, while I was in one of my, uh, transmeditative states, uh, Mother Ya came to me and said, "I, I can't help you with the funny, son. I'm so sorry." Okay.

So, just to be clear, when you did this, it was a fully supervised. Oh, god. Yeah. Activity. I, you know, they are licensed. They're fully supervised, and they have medical staff on on hand. It wasn't somebody who sold you some on the street. Nobody on your back, by the way. Now, that I do not recommend. I say, please find a professional and have somebody there to supervise. Make sure that there's medical staff on hand. Do not go to somebody's house. Okay? And do not go to some dude with a ponytail who's just like, "Dude, I've been a shaman for like so long now, and I would love to turn you on to the universe." Yeah. But if he doesn't have a ponytail, it's okay. And it's, and it's not a party drug. No, it's not. Yeah. If you're looking to get high, don't do it because it's not that kind of high. Right. Yeah. Yeah.

So, like, one of my speculations is, I mean, again, partially based on, on, on self-experience. So there's different phases to the psychedelic experience. You, there's the, the initial, you know, rush that you get, and with a lot of visual and auditory experiences, but then it has this long-lasting effect. I mean, at least 24 hours that you notice it if you pay attention to it. Was your ability to communicate and to talk that you've never talked like this before about yourself and your emotions? And, and then even past that one experience, a lot of people say that one experience, just like you said, can have a, a life-changing effect because from now on, you're going to look at the world differently. So I, I, that's easy to understand knowing that it interferes with brain neurosynapses. How does that connect back to the gut? Well, the slow effect, you know, I mean, the thing that, what, what happens in your brain initially is a fast response. It's being absorbed in the small intestine. Oh, because you ingest it. Yeah. You ingest it, and it's got to get through your. So it only gets to your brain as the, as the microbiome allows it. Right. True. But it's, it's the part that is not absorbed in your small intestine, which happens immediately after ingestion. It's the part that goes down to your colon, and then these longer-lasting effects. I would not be surprised if they're mediated by microbial, you know, they add things to it when they stimulate it with the 5-HT2A receptor. They produce other molecules that then create this long-term experience.

All right. Given that there's this connection, there's so many other psychological features of human behavior, some good, some bad, some failures of our psychological profile, neurological diseases, this sort of thing. How much of that can we blame on our microbiome? Our current knowledge is pretty much based on what we call association studies or correlations. You take a big population of people that have a particular diagnosis, and then you look at their gut microbiome, and it's different. You have to even know to do that as, as part of the study, right? But it doesn't prove causality. That, that's the thing. So I give you a few examples. I, I think, uh, anxiety, in my opinion, I've studied this for, for pretty intensely for the first part of my career. We know so many mechanisms in the brain that, you know, and the effect of early life adversity that predispose you to have greater anxiety. So we know so much about the brain mechanisms that some people try to propose, you know, it's your microbes that cause anxiety.

Has, has any of your research gone into diet in relation to Alzheimer's development? Yes. So we're part of a big, um, US-European consortium on Alzheimer's disease, funded by the NIH. There's definitely pretty strong evidence that the NIH, National Institute, National Institutes of Health, said about that. Thank God. Thank God we have it. Yeah. Well, thank God we have it now. What time is it? What time is it? Let me tell you something. Now you sound like Flavor Flav. Yeah. And I would say there's, there's pretty solid evidence that, again, what we call dysbiosis, or altered composition of the gut microbiome, plays a role. And there may be heterogeneity, you know, it's not Alzheimer's is not one disease, maybe different pathways. Diet and what we now, you know, is become sort of the magic word, systemic immune activation, or systemic inflammation, is clearly one of the main risk factors for not just Alzheimer's, but also all the other ones like Parkinson's. And, but, um, Alzheimer's is also, it's, it's interesting. So anything preventive for any of these chronic diseases, you want to go to what's been referred to as an anti-inflammatory diet. Basically, that's an emergent awareness of our health. Is that, is that butyrate anti-inflammatory? The phen, yeah, and butyrate, polyphenols, and those sort of things. A large plant. Once you have Alzheimer's severe symptoms, there's evidence that a ketogenic diet, you know, which is not a good diet for the average person because it starves your microbes, but in that case, it's beneficial. And there's one disease entity, refractory seizures in young children, where ketogenic diet is also. My god. Ketogenic is, is basically protein all the time, fat and protein. Fat and protein. Keeping your body in ketosis, a state of keto, right? Right. Which means that you don't have access to sugars or any carbohydrates. Your body basically uses just the fat. Yeah. So, and of course, presumably before we were agrarian, our ancestors, they ate dead animals, right? Or berries, of course, if they could find them. But, uh, they were, that the caveman diet, is this correct?

Well, but, you know, going back to my personal experience on the, as a caveman, you had to say that. No, it was, it was, I was just hanging there. It was just hanging there. I didn't. Living with the Yanomami on the Orinoco River. I mean, so they're surrounded by, by animals, you know, by birds, by fish, the big mammals. They only eat a very small amount of, of, of, of animal products. They mainly eat tubers and berries and plant-based stuff. That's why they have the healthy microbiome. That's why they have the healthy microbi. And, and that has been studied all the way. A colleague of mine at UCLA, Ela Sha, all the way into the production of neurotrans, of GABA, this inhibitory neurotransmitter in the brain. On a ketogenic diet, that's sort of like Valium, you know, it, it sort of tunes down the nervous system.

How, how much of this is us really knowing a lot of it, or how much of this is us just beginning to understand? I know you've been doing this research for decades, but just how much more of this do we not know yet? What can we look forward to? Yeah. I, I think we're just scratching on the surface. Surface. Oh, really? Yeah. I think. Well, I was just think about these millions of, of genes that the microbes have. We, we only know. Why do they have more genes than we do? That ain't right. Yeah. Been around a little bit longer. Or, or is it the collection of genes represented in the diversity of microbes that you're referring to as millions of genes? Okay.

So, if someone prepping for a colonoscopy, they just got rid of the entire population of microbes. So, why, other than the value of the exam to prevent colon cancer, how do you get back your microbiome if it's all in the toilet? It comes back fairly quickly. You know, it, I, I would say, where's the recipe? Wait, who's who? Oh, the. So, so the blueprints to reassemble it is in your gun inside. But don't. I'm asking the medical doctor here. Well, I'm telling you. Did I ask the two of you? No. But you got it anyway. Yeah. So, you need to know. So, okay. So, you're saying we, we are chemically equipped to reproduce the microbiome that is suitable for us. So, there's a form of colitis or a very serious form after antibiotics where you basically just destroy your microbiome. Yeah. Um, oh. Because the antibiotics, while it's getting rid of whatever was your condition, it's, it's, it's biotics. Killing everything. So it's called C. difficile colitis. That's that, that's the. So one therapy that is very effective is a fecal micro-transplant. It's the only disease where that works. A poop transplant. It's a poop transplant. So whose poop are you taking? Oh, you had to ask. Uh, I'll tell you this, not dog poop. No. So, there's now people have identified donors that are free of any disease, any family history of disease. So, and that have a diverse, healthy microbiome. So, these are the donors. So, one of the most effective therapies is to get one of these transplants, these poop transplants. And so, for a while, then the person who got this transplant has the microbial composition of the donor. Yes. Because he, he or she himself didn't have it. But if you look at this, like a few weeks later, a few months later, the person's own microbiome is being reassembled. And the reason is possible because the microbes are not just floating inside the lumen, the inside of the gut, but they also inhabit the mucosal lining. And that's probably where that information is stored, of the blueprints. And that's exactly what comes back. Yeah, I did say that earlier, but that's okay. That's, I, you know, I don't need to be right. I just need to be funny. But if you're right and funny, I guess right.

So what about advertisements for gut ailments? And every time I see one, I say, "Do I have that? Or could that happen to me?" And one of them shows up a lot is IBS, or irritable bowel syndrome. Do we know the cause of that? And can gut health fix that? Yeah. So, yeah, this is something that myself and my group have studied for, you know, like, I would say, four, four decades. You're failing badly because people still have it. Get back to work. What are you doing here? Well, fortunately, finally, after 30 years of, you know, writing articles and review articles on it, it's basically called a, a disorder of altered gut-brain interactions. They did bring the brain in. How about finally? And it's the most effective therapies are brain-targeted therapies, meaning simple relaxation techniques, mindfulness-based stress reduction, gut-directed hypnosis, cognitive behavioral therapy. They're better, more effective than any of these medications. Now he's getting all new-agey on this. So how is this received by, quote, Western medicine? Yeah. To have these, a lot of resistance. And also the pharmaceutical industry. Of course, you need a pill. They need a pill. They need a pill. Yeah. You can't meditate a pill. So, you've got, I mean, we're getting inundated with supplements. We're getting inundated with probiotics. I mean, probiotics, too. There's all these, you know, eat this yogurt 'cause it's got the, the, the, the bacillus, the, the active microbes. Do we really need that?

So the official organization of gastroenterology has published, you know, they always publish these, these statements, these, uh, expert statements, and they said there's not good enough scientific evidence to actually recommend probiotics in general as a treatment for IBS. However, there are patients, you know, who benefit. And there's also, there's different types of probiotics. If, if now go on the internet, you know. Yeah. Yeah. It's a whole industry. Yeah. That's the whole industry. And like when I wrote my book, somebody came to me who was a retired, um, Ulip Packard engineer, and said, "You want to be my partner? I want to start a probiotic company." So we, so we just go to these big warehouses and get our organisms and then we package them and then, you know, market them. So that's a lot of people have, have. And you said no. And he's a billionaire now. Is that what you're saying? I have not seen him since then. I don't know.

All right. So, there's a lot on the table right now, and, and we're inundated by ads that are telling us one thing or another about medicines that are being put forth. What would you say is a best practice going forward? Not that you're prescribing for an audience that is surely diverse, but what kind of things should we be aware of as we put food in our pie hole? I love that. Just a glimpse on your diet. So don't judge me 'cause I like pie.

So first of all, I would say it's not just the food, you know, it's the lifestyle. It's the food is a big part of lifestyle. Same with the Mediterranean diet. I never, I, I no longer call it the Mediterranean diet, but the Mediterranean lifestyle. If you go to Italy in summer, you will experience that the social interactions and the, uh, which is a big part of it, you know, like all this go back around, go back further than that to the soil where our plants come from, and that the animals eat that, then it comes down the food chain to us. Yeah. So, like the awareness of, of, of why your gut health may not be optimal is key to start out with, because then you realize it's not just, it's not just what you eat, but where it's grown and how it's grown, and how do you eat it, and in which context. And, you know, that's easy to say, but suppose I don't care about any of that, and I do poop regularly, and what is, what should I be worried about? And I don't have mood swings, I don't have IBS. So, does that make me rare on this spectrum of gut biome issues? It seems right now, you know, all of a sudden, since this has become acceptable as a topic for dinner parties, which, which was not the case even 10 years ago, it seems like everybody now has, you know, like 40 or 60% of the population has some kind of a, a poor gut health, you know. I'm not sure if that's true or not, but wait, but the people you studied, you said they have the best gut health in the world. What is it about them that manifests this fact? Do they live longer? Are they, they never have diarrhea or constipation? What is the metric for you to arrive at that conclusion?

You know, for these people, um, because we should just do what they do, if that's what you're saying. If, if you lived with them, you would realize we can't, we can't go back, you know. There's no, there's no cable. There's no streaming. I'm not eating leaves and grubs and grubs. Yeah. Tasty grubs. They're tasty. But what we know about them is, you know, so they have an interesting thing. They, they have a lot of little wars, and the wars are invading another village to get women from other villages, and they do this to prevent, uh, inbreeding, you know. So this is part of their culture that they always, they could just have a dance, you know, just, "Hey, everybody, social." Yeah. Just come on over here. We're going to have a little dance. Y'all meet one another and, you know. Anyway, so sorry. Um, so a lot of them die early because they get bitten by a snake or eaten by a crocodile, or a lot of good that the, the healthy gut biome did for them. But, but if they don't have, but that crocodile has the healthiest gut of all the crocodiles. Yes. And that's why crocodiles smile.

But here comes the interesting part. If they don't die early from one of these accidents, they live into their 80s without any medication. With no medication. No medication. And no and no medical system. And no medical system. That is impressive. And no medical insurance or anything. We don't need it. Well, we don't have that here either. So, let's be honest. This is America. We do not have healthcare. All right. It's an illusion. People, don't get mad at me. Vote differently. Okay. All right.

So, you've spoken of a mixture of traditional western medicine and lifestyle, a diet, uh even sort of eastern philosophies and ways of living. Is there a way to sift the fact from the fiction for someone who's just exposed to all these ads and and other YouTube videos? Someone seeking guidance and not being inundated with all of this misinformation. Thank you. Very difficult for the for the average person. Very difficult, especially in today's media climate. And it's going to get worse, you know, for political reasons. I think we're going Listen, don't blame me. I'm very healthy. I have a doctor who said that I have am the best health that anybody could ever be. You know it and I know it. So healthy. It's what I am. Yeah.

One of my missions at this stage of my career is really to provide that answer for people and the trust and the transparency. I think there always has to be this always has to be evidence supported and the evidence could come from scientific studies high quality not you know five mice and then claim that this is but it also can come from um traditional success if I I have this develop this criteria somebody is stuck around for five or six thousand years there's got to be something to it you know you cannot you cannot just dismiss it turmeric is a good example so true anti-inflammatory. There's now scientific studies. Jinseng is another. So there's there's several things that I think you can but then there's obviously in in in the middle of all of this is an enormous number of stuff that's placebo. And placebo is not a bad thing if if people feel better and they want to spend the money. People poo poo. I shouldn't use that phrase. You know, people denigrate placeos, but if it works, we should study placeos. Yeah. And so there's a lot of you know high high quality research on the place on the brain's mechanism to that gut brain connection the placebo if your brain perceives that it's working. Yeah. So the placebo is a evidence-based therapy that the body does itself. You know it's not it's the enemy of the pharmaceutical industry obviously that's why it's badmouth. It's it's a wonderful thing if if you're a really good doctor and healer, you utilize the placebo response extensively. Interesting, isn't that? That is that's pretty wild, man. Yeah.

So, doctor, what what brings you to New York City? It wasn't just to do this show with us. So, I have an invitation to this um integrative health symposium that's going on uh tomorrow and into and and to Saturday and I have a couple of one panel on IBS and and one talk about um increased stress responsiveness of people. Okay. Especially stress is a buzz word, a killer of of late. Yeah, we're all stressed. Well, cortisol and stress very uh inadvertably linked. So, well, welcome to the town. Yeah. And uh thanks for making some time in your schedule. And speaking of gut biome, don't eat any dirty dogs. Okay. Hot dogs. Yeah, man. Oh, no. That No, you need that. Yeah. You know, you got the guy with the You got to live here. See, the people who eat it every day Oh, they're they're not from here and do it. It'll kill you. Okay. Yeah. We We built up a resistance. They'll kill you within the hour, right? But you go to the one with the dirtiest fingernails. That's what you do. That's the best one. That's the guy. Don't look at me like that. Thanks Neil and team. It was a pleasure to be here. Pleasure was us sir. You guys are an amazing team. I know we've done a lot of podcast but not not there's not too many out like this. Dr. Emmeran Mayor with a 2016 book Mind and Gut Connection followed six years later by Mind and Gut immune immune connection. Nice. All right. It's all there and more. Gary, thanks for being here. Pleasure. All right, Chuck. My stomach hurts. [Laughter] Well, go talk to your gut and see see what happens. I My gut is feeling just fine. Good to know. Thank you. So, this has been Star Talk special edition. Neil deGrasse Tyson here as always, bidding you to keep looking up. [Music]