What We Got Wrong About the Gut Microbiome (And What's Actually Right) with Dr. Emeran Mayer

Mark Hyman, MD

Dr. Mark Hyman is leading a health revolution—one focused on using food as medicine to support longevity, energy, mental clarity, happiness, and so much more. Mark Hyman, MD is a practicing family physician and an internationally recognized leader, speaker, educator, and advocate in the field of Functional Medicine. He is the founder and director of The UltraWellness Center, Founder and Senior Advisor for the Cleveland Clinic Center for Functional Medicine, a sixteen-time New York Times best-selling author, and Board President for Clinical Affairs for The Institute for Functional Medicine. He is the founder and chairman of the Food Fix Campaign, dedicated to transforming our food and agriculture system through policy.

He is a co-founder and the Chief Medical Officer of Function Health. He is the host of one of the leading health podcasts, The Dr. Hyman Show with 150+ million downloads. Dr. Hyman is a regular medical contributor to several television shows and networks, including CBS This Morning, Today, Good Morning America, The View, Fox, and CNN.

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Full Transcript

Automatically generated. Please forgive any typos or errors in the following transcript. It was generated by a third party and has not been subsequently reviewed by our team.

Dr. Emeran Mayer
But but I think to see the microbiome as a the master translator in in our bodies that translates whatever goes on around us comes into Yeah. The diet and which comes to us through our mind because that goes down to the microbes as well. The microbes translate this information into the body's own language. And if that translation has an end result of a pro inflammatory neurodegenerative message, then that's what where the disease comes in.

Dr. Mark Hyman
Welcome, Ameren, to the podcast again. It's good to have you back.

Dr. Emeran Mayer
Thanks for inviting me, Mark. It's a pleasure. Honor.

Dr. Mark Hyman
Well, it's fun it's fun to talk about poop, which is my favorite subject. They used to call me doctor see every poop when I was at Canyon Ranch because I used to look at stool tests all the time and I wanted to see stool tests on every patient. But you're an MD or a gastroenterologist, you're a scientist, you've been studying the microbiome for a long time. And you've written a book about it that we talked about on a previous podcast, which recommend people listen to, The Mind Gut Connection, a really powerful book. This is sort of a tenth anniversary edition that's come out, how hidden conversations within our bodies impact our mood, our choices, and our overall health.

And I think, you know, science has finally come up with this simple idea that what's happening in your gut is affecting every single system in your body and is related to almost every disease you can think of, whether it's depression or dementia, whether it's cancer or heart disease, whether it's diabetes or multiple sclerosis. Everything in some way or another has a tie back to the microbiome in the gut. Even this whole new nutritional metabolic psychiatry field has emerged since then. I think systems biology is now coming more into the forefront of understanding the body as this complex network of systems, not this structured organ based medicine that we have that's based on specialties that has nothing to do with actually how the body works. It's just an artifact of Vesalius dissecting the body.

So now we're kind of in this field of like, well, what do we know about the microbiome now? What can we do to assess it properly? And how do we actually treat people focused on the microbiome? And a lot of your work is about this in your new book, which is really an incredible manual. It's more like a practice band called the Meyer Model, Optimize Your Health and Wellness with the Brain Gut Connection, is out now.

It's a really good practical application of this and understanding how we can bring our healthy microbiome back into gear. So maybe we can start out by having you kind of frame just the scope of the problem again. Like how big is a problem of the microbiome in health and chronic disease in 2026, particularly in America?

Dr. Emeran Mayer
Yeah. I would say I mean, just building on what you elegantly summarized, you know, that would would we're changing our view of looking at these interacting systems. It's not just the microbiome. It's not a particular microorganism. It's really the the the the system in which these elements interact with each other.

I I think that, so I've kind of you know, from the initial enthuse well, I would say from initial skepticism ten years ago when these first papers came out about how in in mouse models, how changes in the microbiome can alter, emotion like behavior, which I've questioned because we've done decades of research on on these brain gut interactions without the microbiome and had a pretty good idea of how they work. So I I went to my initial skepticism to you know, jumped on the bandwagon, was totally enthusiastic. This is gonna explain everything, and we can cure all our chronic non contagious diseases with manipulating the microbiome. And if if kinda come back to a much more careful view of this, you know, that the microbiome is a we we have a lot of evidence from animal studies that there is a causal relationship between what the microbes actually do and what the result is. We don't have that evidence, the same evidence in humans, unfortunately.

You know, we still have to rely on on correlations, epidemiological correlations. And, so I like to keep my skepticism in terms of, you know, can we actually deal with this with our health crisis just focusing on the microbiome? You know, can we can we just tell people to take this or this probiotic or symbiotic? I I I just don't think it's as simple as that. And the reason I'm saying this is because if if you look at reality, you know, there's so many people like, topic of longevity.

A lot of people live into their become centenarians, live into their hundreds. If you look at these personalities, I doubt seriously that they paid attention to any of these things that we're now No. Propagating from exercise to No. You know, the healthy diet. There's also, you know, good evidence that many of the the negative factors like traumatic stress, by changing the microbiome has this long term effect because a lot of, these centenarians actually Holocaust survivors have gone through the Wow.

Most of your early life stress Yeah. You know, based on a simple model, you would say. So what can we do? I mean, this is coming back to your your your question. The interventions haven't really changed that much.

You know? This is one thing when I when I wrote this anniversary edition and reread the book from ten years ago, there hasn't really been that many novel, if any, practical recommendations that we can give based on the science. We know a lot more about the system now, but the main the the the mostly effective interventions are are are basically lifestyle and diet. You know? That Yeah.

That's that's kind of a paradox. And I don't know if that will change. If he ever will come to I mean, this is kind of another topic we we can talk about and that I mentioned in in in the anniversary edition. This is this is new field and science of these bioengineered probiotics, which basically you can, you know, interfere with specific functions in the body. We don't really have those yet in in hand for clinical use.

Dr. Mark Hyman
Like custom probiotics particular condition.

Dr. Emeran Mayer
Yeah. Yeah. For particular conditions. Like, the one for there would be one for obesity, one for inflammatory bowel disease. You know?

Mhmm. It's theoretically possible that that will happen. I've I've been involved in some of this research with, you know, both the estrogen recycling, but also the inflammatory bowel disease applications. Yeah. We're not there yet, and we we don't have any clinical trials that show that this actually works.

Dr. Mark Hyman
Yeah. I mean, that's the challenge. You know what? I often say the absence of evidence is not the evidence of absence. And I think, you know, the fact that we haven't really had funding, which is the problem, for a systematic approach to treating gut issues is a problem.

And it and it leads to kind of a gap in the scientific literature where you've got a whole group of physicians who are using the clues in the science because there's lot of clues. There's a lot of things pointing to what works and what's helpful. There's prebiotics or probiotics or polyphenols or feeding SIBO or fungal overgrowth or gut repair. I mean, there's a lot of a lot of sort of sort of animal data. There's some human data, but it's it's not a systematic randomized controlled trial.

And that's really just an artifact of our really screwed up scientific paradigm, which is funded mostly by pharma and for things that we will make a lot of money from. But restoring gut health and gut function is not necessarily something you're going to make a lot of money from. So it's been it's been done by a group of physicians in functional medicine. We we have a whole system that we've developed that's based on a framework called the five R program, essentially to reset the gut, which is remove the bad stuff, like whether it's allergens or bad bugs or SIBO or parasites. Replace what's missing.

It could be digestive enzymes or hydrochloric acid, prebiotics, and then, you know, reinoculate, which is probiotics. And then of course repair, which is finding things that help the gut, soothe the gut, whether it's vitamin D or vitamin A or omega-three fats or various kinds of things like glutamine that might be helpful. And then we help restore the nervous system by helping with relaxation techniques and various kinds of nervous system reset. And it's not been scientifically validated, but it's something that's been used clinically like thousands and thousands and thousands of patients. And seems to work, even when we don't completely understand what's happening in the microbiome.

I've experienced that quite a bit. You know, like where I've had, you know, like I had recently had a patient with severe SIBO, bloating, distension, constipation, pain, neurocognitive symptoms, fatigue, brain fog. And I basically treated her with three antibiotics because she had sulfur gas, hydrant gas, methane gas. And I treated her with herbs to help keep things calm down after. And I gave her basically some things to help her rebuild her microbiome, the probiotics and so forth.

And she's doing amazing. I think for those people suffering with issues and it by the way, you can have gut problems and have no gut issues. That's a big thing I want to talk to you about. But if you do, there's usually a way to get through it, and typical gastroenterology doesn't really focus on it. So I'd love your perspective on that and and how you think about, you know, kind of bridging that gap.

Dr. Emeran Mayer
Yeah. I I find that what what you just said is really interesting. So if you had talked to me ten years ago or fifteen years ago, I I would have said this is you know, I don't believe it. There has to be evidence based. You know, we have come to so many breakthroughs in medicine with the traditional model and the the the randomized controlled trials.

And in the meantime, I've I've sort of changed our view. So mornings, I I feel, you know, there's there's there's a lot of affinity I feel with the functional medicine approach, you know, and I've got invited to meetings, which always has surprised me in the beginning because I've not talked that pleasantly about functional medicine. But it is just the second one is, you know, there's this whole historical evidence based, body of of of of evidence from from from these ancient healing traditions. You know? So if people kept something like turmeric, for example, over several thousand years as a remedy and an anti inflammatory compound, it can't be wrong.

I mean, people would not be that stupid to to to take something that has absolutely no effect or no benefit. And there's many of these examples. So that historical evidence for me is also, you know, one one point that I sort of, realized. And and also realizing the shortcomings of to randomized controlled trials. You know?

Clearly, having done many of these studies and having seen that, you you know I mean, the heterogeneity of people, that's kind of one of the big problems. You know? I mean, yeah, in in inbred mice, you can do a randomized controlled trial. Yeah. 100% positive.

You know?

Dr. Mark Hyman
Right. Right. But humans are not are not all inbred identically, genetically, and and they all have different backgrounds and different genetics and different microbiomes and different lifestyles. And it's it's definitely a problem. And I think, you know, that's that's a fundamental flaw in the scientific model that we're using, and we don't know how to create n of one studies, which is basically what the NIH now says the highest level of evidence, which is if you have a single person, you can use them as their own control before and after treatment and measure the changes or outcomes.

That's a validated measure. And then since we call those anecdotes, but actually if they're systematically done, they they actually tell you a lot of information.

Dr. Emeran Mayer
Yeah. It's gonna be I I find that interesting for myself that I would ever you know? But being a, you know, hardcore scientist, I've always been open to I I have my own hypotheses. And if they're not confirmed by reality, then I abandon them. I'm gonna move move on to better hypotheses, and that's sort of been happening with this dealing with with chronic diseases.

You know?

Dr. Mark Hyman
Our Yeah.

Dr. Emeran Mayer
Paradigms and our reductionistic hypotheses just don't work for them.

Dr. Mark Hyman
So so maybe maybe you can take a little time kind of going out of this reductionist model that we're talking about and kind of zoom out and go, okay, here's the microbiome. You've been studying it for a long time. You've done a lot of research in this area. How would you sort of explain to people how the microbiome interacts in the body to create so many different health issues? And how do we start to think about with the Mayer Method actually or the Mayer model actually helping people to reset their gut?

Dr. Emeran Mayer
Yeah. So there's one simple story that that, you know, I I tell patients. You know, there's there's a lot of beneficial molecules. The microbes generate metabolites from our diet and from whatever we ingest. And but there's so there's a lot there's a lot of compounds that cause inflammation or low grade immune.

So when when I talk inflammation, I always prefer low grade immune activation because you don't get the same inflammation as you get an inflammatory bowel disease. You know, it's not something that you necessarily see on an endoscope or on a biopsy. But at the same time, the micros produce these beneficial molecules. And, you know, so far, our view is limited on this. So these short chain fatty acids, mainly butyrate that, have an anti inflammatory effect and many other health benefits at the gut level and throughout the body and and in in in in the brain as well.

So the the balance between these harmful substances that get into our system and these anti inflammatory molecules, I think, ultimately determines, you know, the the the the health condition of your organ, you know, like your and my main interest has been on on on on the brain. So you could so in theory, you could, you know, do some unhealthy things and have all these these chemicals in in, in your diet. But if you eat a highly diverse diet that's highly diverse in fruits and vegetables, you will generate sufficient amounts of anti inflammatory molecules that counterbalance these negative effects. So you'll never have just a pure positive influence on the brain from your diet. It will always be a mix.

And and I think it is that balance. So that's that's one thing. The second explanation is the microbiome sits at this interface between what we call the exposome, the world around us, and our immune system, microns away from the all these immune cells. One mistake that's being made, you know, in this communication would trigger a lethal inflammatory reactions. It's amazing that that has does not happen normally, so there's many protective mechanisms.

But but I think to see the microbiome as a as the master translator in in our bodies, it translates whatever goes on around us comes into the diet and which comes to us through our mind because that goes down to the microbes as well. The microbes translate this information into the body's own language. And if that that translation has an end result of a pro inflammatory, you know, neurodegenerative message, then that's what where the disease comes in. So I wouldn't say it's it's as you know, people have always said, you know, microbiome is another organ. I'd I'd like to see it as a master translator, you know, which is able to speaks the same language as, you know, the molecules these biological molecules that our brain uses and our nervous system uses, our immune system uses, and the microbes.

I mean, they're all similar, so they they all speak the same language. But you need that translation this translational step in in between to tell the body how it should respond.

Dr. Mark Hyman
So it's almost like the gut microbiome is a transducer from the world to your body that then changes what happens across all your physiology. In other words, what you eat, your lifestyle, toxins, infections, all that is affecting your microbiome. And that in turn is affecting every biological system in your body, regulating it, changing it, modifying it, both from the short chain fatty acids that get absorbed, but also the microbial metabolites. Yes. San Jason at Cleveland Clinic asked him once, how many of the blood metabolites that are existing in the blood, and there's maybe 6,000, how many of those are are from the microbiome?

And he's like, think a third or half. I don't know if that's true, if there's any evidence to that. But is that true?

Dr. Emeran Mayer
That is true. And you know, the problem is we don't know for most of these, we don't really know with the exceptions of TMAO, for example, that you know, the Sanhazen example or certain tryptophan metabolites, like canurine. For most of them, we actually don't know, or we only know it in a reductionistic way. So people have used one of these metabolites, put them on on a cell culture and see what happens or, you know, on a into a mouse model. But that's not how these metabolites act.

They all interact with each other. It's, again, the system's biology concept comes in. It's a whole network of these what you may call, you know, potentially harmful metabolites and the beneficial metabolites that constantly interact and compute the outcome. And the outcome in general in a healthy person is always positive, which is amazing. I mean, you know, considering what we put into our bodies and are exposed to an environment now with the microplastic, it's absolutely amazing to me the resilience of that system.

So the engineers of evolution, you know, have done a masterful job.

Dr. Mark Hyman
That's true, that's true. But I think we've really hardened microbiomes in the twenty first century. We have an increased rates of c sections, lack of breastfeeding, early antibiotic use, increasing toxic load, increasing food sensitivities, I mean food additives, emulsifiers and other things that destroy the microbiome. And then we end up with poor diets, low fiber, ultra processed food, and the list goes on, stress. And and all of this is affecting the microbiome directly.

Dr. Emeran Mayer
If I can comment if yeah. If I can comment on this. So, yeah, it's the system is masterfully designed over millions of years or billions of years, I would say. The the last hundred years have created a mismatch of that system with, you know, of of the microbes that have adapted rapidly adapting to all these environmental changes. Because with the millions of genes, you know, they have this they're much better in doing this, but our bodies have not.

Like, the immune system has not been able to catch up with this. Nothing has prepared our immune system for what we're experiencing today. And so there's now this mismatch between the microbial world, that is adapted to what we put in and feed it and expose it to and our much more conservative human biology, you know, that so this response of inflammation is basically a a a response to the system doesn't recognize this dramatically changed microbiome world. You know? It's, even though it it may not necessarily be harmful to us, but that does now the immune system rings the alarm bell because what it sees that these microbes now, there's fewer of them.

There's more, you know, pathological molecules, fewer beneficial protective molecules. And yeah. I I mean, I like this concept, the mismatch of that has occurred in the last hundred years. That that's in some ways the main problem that we're facing. And how are we gonna deal with this?

Ultimately, I'm I'm not exactly sure. You know, we we we can try all kinds of things we do right now, but unless we change the environmental situation, which I doubt we will, you know, it's it's hard to say how we hundred years from now what what what this looks like.

Dr. Mark Hyman
Yeah. Well, we we have to take care of our microbiomes, and I think there's a whole I mean, a whole evolution of this research that's pointing to more specific personalized probiotics, prebiotic foods, the role of polyphenols, all the colorful plant compounds that help fertilize the gut, fermented foods as an intervention. And so there's a lot of things that you can do to really take care of your microbiome. I think most of us don't think about, oh, how am I going to care for my microbiome? They go, I'm going to exercise for my muscles and I'm going to make sure I sleep and I don't need too much sugar or whatever for my health.

But people don't think, oh, there's this whole organ in there that I really need to pay attention to and I really need to take care of. So if if if people haven't thought of that, they need to. And when they think of it, I'd love you to sort of walk through your model, the mayor model that you developed, of of how to really take care of your microbiome in a in a microbiome unfriendly world. That's what we live in.

Dr. Emeran Mayer
So I I think the first thing you have to realize that, you know, I I've created these pillars that all influence healthy longevity and health. And at the center of of this flower is the brain gut microbiome system, this complex system, bidirectional communication from the brain to gut to the microbes and back, you know, which I would consider the main homeostatic organ in in our in our or system in our body. So the first thing is we have to realize that the second one, we have to realize that the influences, which are the petals of the flower that influence the that end result of homeostasis, the weight of these petals varies between different individuals. It's very personalized. So, I mean, the petals of these influences are you know, food is one of the most important ones, exercise, mindfulness, resilience, community, con connectivity connections, purpose, and sleep.

So these seven influences, they all have variable influences in in different individuals. So in some person, it may be diet plays 100% causes 100% of the variance of the end result of homeostasis and balance. If somebody else diet may play 20%, you know, they may be on a very unhealthy diet, may not exercise, but have a very strong sense of community and, both socially and spiritually, and that compensates for this. So I I think the main thing to realize is we're we're not all the same in terms of the importance of these influences. And so we have to design.

Every person has to design. They have to look at themselves or their the health care practitioner has to look at what pattern does this individual, fit in, And then focus on building up the things that are, you know, are are the most important in in in in that person. So would I tell somebody, you know, who has metabolic syndrome, is obese, doesn't exercise, probably would wanna walk on all of these pedals, you know, slowly? And that's what I, you know, propose in this in this Maya model book. Do it gradually.

There's there's no you know, you don't have to do this well, you can't do it within a week. You have to gradually, work on all these challenges. And, ultimately, you you will feel that you become in charge of your health and your your overall resilience and and and and and balance, and you will decrease the risk of developing chronic diseases. So, I mean, the first is buying into the model, this seven pillar model. Other people have proposed this similar kinds of models as well.

We have to get away from one thing that if if you do if if you meditate five hours a day and do nothing else for for your health, it's not gonna help you. You know, monks don't live into their hundreds. You know, they they usually I've always looked at this when I was, you know, trekking in in in in in the Himalayas. Yet you don't see people that live into their hundreds. You know?

They that's not their goal anyway. You know? It's a that's Yeah. But but now our goal is healthy longevity. I mean, I think, you know, society has finally recognized that this is a for the the the most important goal, healthy longevity without billions of, pharmaceutical products keeping us alive.

And for that, I think you need to have a whole program. I think that functional medicine also proposes that. You know? You don't say to somebody, you just have to take that one supplement and we'll take care of it. So it's so I would say all of these things will be reflected in a change in the microbiome, which is interesting.

So you would think, so why does sleep affect the microbiome or a sense of purpose or sense of community? But studies have have have shown that. It's reflected in a healthier microbiome characterized by generally increased diversity and richness and increased number of, anti inflammatory producing organisms. Yeah. This is my main insight in the last ten years, I think, coming from the mind gut connection to this holistic program where the microbiome still plays a central role, but it's it's it's sort of a readout, which is is a good thing.

So when when we do stool tests and I think we we are getting better in interpreting these stool tests. I still think we're not there where we wanna be ultimately, that we have a a readout and a with a predictive value. You know, are you at high risk for Alzheimer's or when you do this in your twenties or thirties? But we will get there. I I think that the technology is advancing and also AI, how to interpret these, you know, massive amounts of data you can get out of the microbiome.

Yeah. I would say the microbiome is is an excellent readout better than most of the other components or organs in our body.

Dr. Mark Hyman
I mean, think it's quite an interesting model you're talking about because you're saying basically you you are understanding now that outside influences are thoughts, feelings, experiences. All these things affect the microbiome, exercise, stress, sleep. It's bidirectional though, because also the microbiome affects all those things. So it's kind of this conversation that's going on all the time between the microbiome and the brain. And I think I remember when we were trained in medical school, you're a little bit older than I am, think, but we learned that irritable bowel is a functional bowel disease.

And it was we joked that it was super tentorial, meaning it was all in your head. And that we identified that people were anxious and that was why they had this problem. And we kind of blamed them in a way because it's your fault, you're just anxious, that's why you have these digestive symptoms. But I remember a paper, I think it was in JAMA many years ago where they I forget the scientist, but he was talking about the other direction. The the enteric nervous system and the leaky gut and the dysbiosis and the inflammation of the gut was sending signals back up to the brain when there's a dysregulated microbiome to cause brain dysfunctions.

Whether it's mood issues, behavior issues, attention issues, you know, autism spectrum issues, all that is affected. And so I think, you know, your model is really important because it it's sort of both top down and bottom up.

Dr. Emeran Mayer
And it's, you know, it's sort of I mean, I would say I hate to use that expression trendy, but if you look at science, I mean, it's more and more moving into this direction of, you know, systems biology. And, we also do it in our own research. I mean, analyzing these complex data sets with, you know, data from from brain imaging and behavioral and blood values and, you know, the microbiome values and diet. You put all this into a pot, and then you have sophisticated AI techniques work with this data, which you cannot as a human brain comprehend in Right. In, you know, in in a similar way.

So this this is, I think, is happening in many areas, this overabundance of data that we can generate and gather. But we haven't really been able to do the best way in in interpreting it and making creating action items based on individual patterns. So there could be pattern one in one patient and pattern two in another patient. And there's always attempts to do this with this in a simplistic way. Like like many of my colleagues, we strongly believe that I will make the breakthrough in in this.

Dr. Mark Hyman
Let's talk about that because I think what you're speaking to is something really important because there's probably 40,000,000,000,000 cells of bacteria in your gut. There's probably 102 or more times as much DNA from bacteria in your gut as your own DNA. It's constantly making proteins and metabolites. There's thousands of metabolites in your blood from the microbiome. It's almost incomprehensible.

Like the average doctor can look at a panel of blood tests. It's twenty, thirty, 5,100 maybe. But when you're talking about thousands, it's just hard to process all that. And so you're talking about an era that we're entering where AI is going to help us understand the complexity of human biology. And I would really like to hear you kind of talk a little bit more about how this is going to affect our thinking about the microbiome and how it's going to affect the clinical practice of medicine around chronic illness and how chronic illness and the and the microbiome are so connected?

Dr. Emeran Mayer
I I think it will, you know, dramatically change the way we look at the microbiome. I still even though, you know, the stool tests have gotten a lot better and some of these some companies use AI to interpret them or put them into context of published data. But I I think, ultimately, we will come up with with conclusions that are way beyond what we're talking about now. You know? It's, you know, this this whole still I mean, the the the the current approach that look at these microbiome tests and look at which ones are outliers from the from a normal pattern, and then you focus on these three or four organisms, and you create a probiotic or a a prebiotic cocktail that will strengthen those.

I personally think that that will kinda disappear, really. I I think we will we'll have footprints. We'll we'll get footprints of people, and then we compare this with tens of thousands of people. And we'll see that the these footprints are recurring in different populations, and we can connect them to, you know, dietary lifestyle patterns. I I mean, this is I think it's gonna happen over the next five years.

You know, we're sort of confronted with this ourselves. We have these these massive datasets, and, you know, collecting the data is one thing, but then really grinding them through this and this analytical mill is is is is still an unresolved issue. So that that's definitely gonna happen. I I think guidelines will follow from that. I mean, the current guidelines, you know, they they often focus just on diet.

If if you look at what happened in IBD first, there was a a recommendation of a fiber poor diet being beneficial for a patient with Crohn's disease. Now we, you know, we have pretty good evidence that a Mediterranean style diet is the best, you know, anti inflammatory intervention you can do if you don't have strictures and and stenosis. Yeah. So I I think we will get much more, you know, rational recommendations. And I also what I see you know, like at UCLA, so so if somebody comes complex patient with IBS, they're not just gonna get the dietary recommendation or a probiotic recommendation.

They also get a behavioral assessment. And then if, like many people that make it to a university clinic, you know, they have the the the the strong brain component being early life trauma, anxiety disorder, depression. It depends on on the population. But in in in in the most severe patient populations, IBS, you can't deal with the issue just with with a with a dietary change or with with an antibiotic. You know?

You have to embed this in a in in a holistic approach, and you need the, you know, you need the experienced practitioners in these areas. Gut focused psychologists, you know, gut CBT, gut hypnosis, kind of specialized people. So I I I I think it's already changing the system when I look at what happened at at UCLA since you know, when I started there, we we first started a clinic like this, a holistic clinic, but it took a long time. It took, like, almost forty years before this is now becoming an official program of our GI division. You know, that.

And it's it's happening in other universities as well, in other settings as well. So I I think we're moving for some and I shouldn't just say it's important for IBS. I mean, same situation in inflammatory bowel diseases, you know, where we get quite a few people that do not respond satisfactorily to to biologic, you know, to biologics where increasing the dose of the the the medication is not gonna do it, but you have to identify mechanisms that in which the brain basically drives the inflammatory condition in in the gut in addition to what goes on in in in in the gut.

Dr. Mark Hyman
It's it's it's quite it's quite an exciting time for the microbiome, would say. I think we're learning so much. I want to kind of dive into another part of the conversation, is about longevity and aging and what happens for microbiome as we get older. And there seems to be some interesting literature around, and you've discussed this around the microbiome in Parkinson's and Alzheimer's. And the question is how do we think about the aging microbiome?

It in the hallmarks of aging now, which is the features of aging, it seems to be one of the things that goes bad. And it seems like it's a modifiable risk factor. We've looked at really exceptionally healthy older adults and centenarians, and their microbiomes, I wonder if they're different. So maybe you can talk about some of the aspects of longevity and the aging microbiome and how we need to think about that.

Dr. Emeran Mayer
Yeah. So the initial studies were done, you know, on on selected populations, like in in homes for older people. And, you know, there was a confusion of how much the change in the microbiome, the decrease in diversity and richness was actually a consequence of this dramatically changed lifestyle in these retirement homes or nursing homes, both in terms of diet, particularly in terms of diet, but also in terms of, you know, loss of purpose and, you know, loss of social interactions. But we know in the meantime, that's one factor, and many, microbiome studies have been affected by this that that have not been controlled for factors other than age. So we know that, you know, I mean, the microbiome diversity is fairly well maintained through age from midlife to age.

There there are changes. If you compare microbiomes from different people, they become more different. So, some more a more individualized pattern evolves. There's a decrease in in in in certain microbes that play a role, for example, in bile acid, metabolism, in in in the gut. So I I think we've slowly getting a a fairly good picture in somebody that is is a healthy centenarian.

It's not a simple explanation that we we we gave, like, ten years ago. Just a decrease in diversity, and that's why they're more prone to develop diseases. It's it's really, it's it's a much more new nuanced What's happening then? I I think there's there's dramatic changes in these factors that we talked about earlier, these these pedals that influence the microbiome. The exercise obviously goes down pretty dramatically in the majority of people.

Food, unless you can afford to have your 30 different plants and vegetables a week delivered to you, you know, will decrease in variety. So this this decrease in in in in diversity and this decreased prevalence of the beneficial microbes is definitely a risk factor for the manifestation of of of many of these diseases that come with older age. But we have to realize these diseases like Alzheimer's and Parkinson's, they start at the microbiome level in in our forties. You know, there's more and more studies that are showing that you can actually predict changes based on, you know, microbiome you know, negative changes early much much early life. So but then when when when the microbiome goes down in its its in in its main functions, the disease actually then becomes apparent.

You know? You could probably it's it's sort of a good way of identifying what we can intervene. So we can intervene at at midlife in patients at at high risk that have absolutely no symptoms, but we can see some signs on the microbiome level that indicate don't guarantee, but indicate that this person is at high risk. But we can certainly once the first signs and symptoms of the neurological disease, and I've talked particularly about Parkinson's and Alzheimer's, to really aggressively reverse the changes that are going on within the gut microbiome. I would say at that age, probably diet will is is more successful, more more practical than than some of the other changes, but also just connectivity, purpose.

I mean, all these things, I think that Mhmm. So many elderly people, you know, we had this this epidemic of of loneliness, which is definitely it's it's reflected at the gut microbiome level as well. You know? It that's kind of the intriguing thing. It's like this you have this mirror inside of you.

Mhmm. The the better we get in identifying the subtle changes that reflect environmental influences, the better we'll be in in preventing them and treating them aggressively. If he had a full blown disease, I I don't think you need to do a microbiome test. You know? It's not gonna it's not gonna change somebody who has full blown Parkinson's disease with all the neurological symptoms.

Not gonna not gonna make a difference. Same with the same with Alzheimer's. In Alzheimer's disease, it's almost like the opposite. You know? You want there's evidence that a keto diet is actually beneficial because it has anti inflammatory effects on on on on the brain in somebody who is you know?

Dr. Mark Hyman
Yeah. Yeah. I've seen that. I've I've treated patients with Alzheimer's and they use keto diets, and it it has been remarkable to see the way it impacts them. And I think the question I would have for you is now, so we think about taking care of a microbiome and the aging microbiome as a thing in terms of contributing to acceleration of aging through increasing more of a sterile inflammation in the body and affecting every other system.

Let's kind of walk through practical steps. Because you mentioned the 30 plants. I think that's important. I think I want to talk about the specifics with you of what what you actually recommend to people so that they can keep their microbiomes healthy as they age?

Dr. Emeran Mayer
Yeah. It's it's actually not too different from what I would recommend, you know, to to all my patients. And, I mean, it's it's it's kind of sometimes it's it's kind of embarrassing to say that, you know So so so with all this fancy science that we have and all these subtypes and and and personalized and diet that the approach is is fairly standard, you know, the overall approach. It has to be sort of standard concept or, like, the the 30 or 35 plants and vegetables has to be adapted to the taste preferences because food has to be enjoyable. A major function of food on our health is the enjoyment and the pleasure.

It's closely linked to the centers within the brain. So I I would say, you know, start with a, with a breakfast bowl that has many of the the ingredients, seeds and, oats and, chia seeds, fruits, fermented foods in it so you can easily come up with five to 10 ingredients that you add a spoonful to that morning bowl that you have rather than just have your yogurt with with blueberries. I I think more than than ever, you wanna avoid the ultra processed foods. You know? Yeah.

Eliminate them from your diet.

Dr. Mark Hyman
And and the reason is that the the science is there that it it damages your microbiome. So 60% of our diet is ultra processed food, that is directly damaging our microbiome and it's increasing what we call leaky gut because some of the emulsifiers and other additives. So it's not and artificial sweeteners affect the microbiome. So people think, oh, it doesn't matter. But like it it's such a big deal that I think if if one people could do one thing is is swap out algae processed food for real food and eat a lot of plants.

Right?

Dr. Emeran Mayer
Yeah. And then, I mean, just to make it practical, you can create salads, not not the typical lettuce salads that now, you know, get a a bad rep because of this this this these infectious diseases. Cyclospora. Yeah. So we've experimented this at home.

You can easily add 10 different vegetables to a to a salad to a complex salad that so if you start your morning like this and and and your day with with a salad like this, you actually already, you know, fulfill these these these criteria, and you avoid the ultra processed foods, particularly, you know, sugary stuff. I mean, you know, we still don't know exactly with the ultra processed foods. I mean, there is this controversy about this concept that it's it's too loose and not and some people say it's it's it's all the sugar, but that's definitely not not all of it because No. No. Like, all the chemicals, they don't even know what they are.

They're printed on the label. It's kind of amazing. Like, on on an on an airline, you look at this thing with your so called pretzels. The pretzels are the the the minor part of this this

Dr. Mark Hyman
And if it's a minute package, unless it's got simple ingredients that you recognize, it's definitely not not good for you. Do you focus a lot on prebiotic foods for people? Because I think there's more and more data on prebiotics and polyphenols rather than probiotics as a benefit because that really changes over time the composition of your microbiome. Whereas probiotics just give you something additional, but it doesn't really sort of shape the bugs that are growing in there.

Dr. Emeran Mayer
Yeah. And coming back to this, I mean these 30 fruits and vegetables. So from most vegetables and and I I mean also for some of the fruits, fiber is obviously a very important component, health promoting component because microbes are masters. I mean, they love the fiber because they it's they break it down in their to their own food, main food source, but they're also converted into, like, these short chain fatty acids again. From a lot of the fruits, you you get the polyphenols, and that's a group that sort of been, you know, I would say mislabeled or misrepresented in terms of calling them antioxidants because it's a very interesting part of our diet just like fiber.

Yeah. It's not absorbed in our small intestine. The molecules are too big, so it has to be broken down the same, But the polyphenols are broken down in the gut by the gut microbiome into smaller molecules, which are then both, again, food for the microbes and are absorbed as health promoting phenols and phenolic compounds that circulate in the in the in the body. So and there's some very good studies. People always forget that, you know, with some polyphenols like, flavonols, for example.

There's there's studies that reach all the way from molecular studies, showing that they, you know, foster vasodilation of small blood vessels both in the heart and in the brain, increase nitric oxygen production with the vasodilator. And so we know the mechanism, how they actually protect these organs, both the brain and the health. And we have clinical outcome data from pretty well designed clinical trials. So this is an exception. You know what?

So I I think this is often it's it's it's often swept under the carpet that people say, yeah. The antioxidants. Yeah. It's good to have antioxidants. It's it's something it's something much bigger than that.

You know? It's

Dr. Mark Hyman
Yeah. They're kind of what I call them, biological response modifiers. They basically are signals or chemical signals that regulate all sorts of systems in your body. And I think we co evolve with all these plants to do all these things for us, particularly a microbiome. And we have to feed ourselves, we also have to feed the microbiome.

And I think the focus on more prebiotic foods, more fermented foods, more polyphenols, These are things that are different than just taking a probiotic that I think people really can learn about. I think you could probably cover this in your book, right, The Mayer Model? And talk about these various aspects of how to optimize your diet for your microbiome.

Dr. Emeran Mayer
Yeah. And I always emphasize this point. You know, it's it's actually it's actually quite easy to find the right diet. If you've if you identify a diet that's beneficial for your microbes for the the diversity and the health and the richness of your microbes, that's the best diet for you as well because we have lived with these organisms for, you know, millions of years. Our ancestors, you know, prehuman ancestors done that as well.

So I always say it's the the the general advice is eat what's best for your microbes. And, the two main categories that pop up are definitely fiber, prebiotics, and, and and and polyphenols. I mean, there's obviously many of these other vitamins and and and micronutrients that you can add in, but the the main workforce are really these three groups

Dr. Mark Hyman
of ingredients. So there's the fiber, the polyphenols, and the prebiotics. I'm not clear on the third thing. It was prebiotics and polyphenols, and then the third part of

Dr. Emeran Mayer
Yeah. I mean, so the I mean, the third thing that I recommend for the diet is is, you know, naturally fermented foods. And the reason I'm saying this because, you know, people always talk about, you know, yeah, I mean, when when did people start eating yogurts? But there's thousands of years history of our ancestors fermenting food products in in order to preserve them, not for their own health. So our immune system and our, you know, gut had enough time to adapt genetically to these fermented foods.

Again, the the larger the variety of these fermented foods components is, you know, the better we think. I mean, variety is always sort of a a key component in the recommendations. It's not just what you eat. It's it's what variety you eat and how often do you eat it.

Dr. Mark Hyman
Yeah. And I think, you know, you're saying more specific. The there's a lot of specific foods that you can eat that are helpful. And I, you know, I try to cook these and eat them regularly. One is like garlic, onions, shallots, leeks, they're great prebiotic foods, asparagus, dandelion greens, beans, lentils, chickpeas, oats, barley, cooked potatoes that are cooled, rice or pasta that's cooled, makes it more easy to starch, green bananas.

There's a whole bunch of these that are really great. I think there's also polyphenols. Like I know, for example, cranberry, pomegranate, green tea, and a lot of the colorful compounds really help a lot. Those I've used personally to help my own microbiome, and I see a change for it.

Dr. Emeran Mayer
Have you ever had a microbiome? I'm sure you had multiple stool microbiome tests done.

Dr. Mark Hyman
Yeah, yeah. Oh yeah, I've had them, and they definitely change and they shift in response to what I'm eating and my overall health. So I think, you know, the bottom line is it's hard to change your microbiome through probiotics, but if you use the fermented foods, the prebiotics, and the polyphenols, you're naturally going to be growing a better garden essentially inside your gut. And I think I think it's a really empowering thing to sort of start to think about when you're eating. Actually use the science around what your microbiome likes to eat to feed them as well as yourself.

Dr. Emeran Mayer
And it's not you know, it's it's it's not rocket science. It's it's actually fairly straight. Once you accept that that concept, it's it's not rocket science. It's and it's it needs to be pleasurable. Like, I mean, I always emphasize this, you know, if you go to Mediterranean countries, I mean, they love their food.

It's they don't eat it because it's healthy. You know? They

Dr. Mark Hyman
Yeah. Yeah. They eat it because it's good. It tastes good. Right?

That's right. And if you eat this way, you can make delicious food. I think about just being more deliberate. And also just being aware of all the things that harm your microbiome. I think it's important to be aware that eating healthy processed food, a lot of different kind of medications, exposures to environmental toxins, all these things will affect your microbiome stress, your relationships, your connections, the amount of exercise.

All the things you talked about in the Meyer model are all things that modify the microbiome in one way or the other. And the levers are there. I think, you know, I'd just like to close by asking you, you know, this is sort of a general conversation about creating a healthy microbiome. But you know, I find it as a target and very specific target in order to treat a lot of conditions that are medical conditions. Using the microbiome as a direct kind of doorway to many, many health conditions, whether it's autoimmunity or allergy or asthma or fibromyalgia or even things like migraines or you talk about the estrabolome, which is basically the estrogen metabolism in the microbiome.

We didn't get into that too much, but that affects women's hormones. So treating the gut can often be a doorway to many, many different problems across many, many different specialties. And I wonder sort of how you how you think about that and where the where the where the sort of evidence is on that right now.

Dr. Emeran Mayer
It is amazing. I'm still amazed about that, you know, and as as a sort of a, you know, physician and scientist, it it's it's kind of against my nature to say there's this this string theory of of of of of health and and and diet that explains everything. But I think the microbiome has has that quality that you could that you could use it as as a and I keep emphasizing its its connections to the brain and the gut. I mean, the gut is an amazing organ. You know, it has all these components in it, immune component, hormone component, the nervous system component, and the microbes know exactly how to communicate with these systems within our gut.

So, I would say, it doesn't surprise me once you understand that, that it has so many influences on particularly the immune system when you think about, you know, almost all the immune cells travel through the gut, and reach a distant distant destinations like what happened during COVID. You know, COVID doesn't doesn't start in in in in in the gut, but the immune cells that are in your lungs have a connection to their past when they, you know, did their migration through the gut based immune system. And so even in and the same with with with the brain. So many cells that end up in in in the brain have a history of encounters with with the microbiome. I I I I I think, you know, we have to be careful not to come up with with simplistic conclusions.

You know, now we know everything. You know? But but I think we have to acknowledge that we've discovered unexpectedly a system in our bodies that is is doing is almost like rivaling the brain, you know, in terms in terms of its complexity and its influences on. It is. I mean,

Dr. Mark Hyman
I think it's we're kind of in the you know, it's a new sort of era in medicine, think, where I think the microbiome has kind of shaken some of the foundational principles of traditional medicine, which is specialty and organ focused, and sort of understands how now the gut is related to every system in the body, and the body's a network, and the microbiome is part of the network. We really have to think more about network and systems approaches to treating disease rather than this reductionist model. And I think what I've found over the years, being a doctor, seeing patients, is that when I focus on gut health with people across the spectrum of diseases, whether it's someone with Parkinson's or allergies or migraines or PMS or you name it, autoimmune disease, that people will get better. That people really do improve. And I see it over and over in a way that's pretty striking.

And I think the methods are still being worked out and we're still at the beginning of this era, but it doesn't mean that we can't apply these principles clinically, practically, because they're very low risk generally. They're very effective often and you know, there's not a lot of downside to eating healthier and managing some of those things, taking some prebiotics and probiotics. It's kind of low risk, and the yield is quite high. So I think it's kind of an exciting moment. So how do you see this field going over the next ten years, and just to wrap up?

Dr. Emeran Mayer
I think there's gonna be bigger breakthroughs in terms of practical applications than have happened during the last ten years. Uh-huh. I I think this is the the science is still accelerating. I think the acceptance by practitioners I mean, you see the increased popularity of functional medicine even for traditionally trained physicians is is keeps increasing for that very reason. And so I think there's gonna be I mean, there's very strong headwinds ahead.

You know, we we're gonna be facing I mean, the next ten years, it's hard to imagine actually what this world is gonna look like from all these multi crisis we're experiencing, which also will affect food production and, you know, environmental exposure, heat, and all kinds of things. But but I think there will be I think there will be a new era of of holistic, you know I hate to use this old fashioned term, but holistic medicine, medical practice that takes into account now all these insights that we get from digesting and integrating all these different pieces of information. I I think people hopefully you know, we see some some efforts that was the Maha movement. I mean, that's something that you couldn't expect ten years ago, you know, that something like this would happen.

Dr. Mark Hyman
Which sorry. Which movement is that?

Dr. Emeran Mayer
The Maha, the m a h a

Dr. Mark Hyman
Oh, ma. Maha. Yeah. Yeah. Yeah.

Make America healthy again. Okay.

Dr. Emeran Mayer
In my opinion, this doesn't go far enough. You know? There's still a lot of loopholes in it that will not do it. But it's it's definitely something something like this could happen, imagine what will happen in the next ten years, you know, that's

Dr. Mark Hyman
Yeah. That's true. It's it's an exciting moment with the convergence of systems medicine, with AI, with changes in health policy, people waking up to the fact that we're we're in a different era. I think it's quite exciting, and I think your work is such a key part of it, and you really contribute so much to the field. I definitely encourage everybody listening to get your first book, which is an updated edition, The Mind Gut Connection, and also the new book, which is The Mayer Model, available everywhere you can get your books.

And the Mayer Model is really about practical applications. It's a beautiful book. It's well designed, and it's easy to use. And I think that it covers seven pillars, really helping your microbiome, food, exercise, mindfulness, resilience, community purpose, sleep, and talks about how you can focus on the right diet, very specific things we talked about in even more detail. And I think it'll help everybody listening to develop a healthier microbiome, which is really the key to good health.

And I think many ancient healing systems have figured this out a long time ago, but we're finally figuring that out in the West. So thank you so much for your work and your contribution and your new book, and I can't wait to see what's going happen in the next ten years.

Dr. Emeran Mayer
Thanks for having me on your show. Greatly appreciate it, Mark.

Dr. Mark Hyman
If you love that last video, you're gonna love the next one. Check it out here.