What We Got Wrong About the Gut Microbiome (And What's Actually Right)

Key Takeaway

Make one meal today a “microbiome garden”: combine several plant foods, a fiber-rich base, and a fermented ingredient while replacing an ultra-processed snack or meal. For example, build oatmeal with oats, chia, berries, nuts, seeds, and yogurt or make a salad with 10 different vegetables and beans. The goal is not a perfect probiotic stack—it is consistently feeding beneficial microbes with diverse whole foods.

Episode Overview

Dr. Mark Hyman and gastroenterologist Dr. Emeran Mayer examine what microbiome science can—and cannot—currently tell us about chronic disease, aging, and mental health. They argue that the gut microbiome is best understood as part of a whole-body brain-gut system, and that diet, sleep, exercise, stress, relationships, and purpose all shape its function. Their practical conclusion: emphasize diverse plants, fiber, polyphenols, fermented foods, and fewer ultra-processed foods.

Full Transcript

Transcript of What We Got Wrong About the Gut Microbiome (And What's Actually Right) from The Dr. Hyman Show. Auto-generated from episode audio; may contain minor errors.

But, but I think the microbiome should be considered as the main translator in our body, translating everything that happens around us, comes with our diet, and comes to us through our minds, because it also affects the microbes. The microbes translate this information into the body's own language, and if the result of this translation is a pro-inflammatory or neurodegenerative signal, then this is where the disease arises. Welcome Emeran to the podcast again. Nice to see you again. Thanks for the invite, Mark. It's nice, it's an honor for me.

Well, it's interesting, really interesting to talk about feces. This is my favorite topic. They called me "Dr. Kaka" when I worked at Canyon Ranch because I was constantly studying stool tests and wanted to see them on every patient. But you are a doctor, a gastroenterologist, a scientist, you have been studying the microbiome for a long time. And you wrote a book about this , which we talked about in the previous podcast, and I would recommend everyone listen to it, "The Gut-Brain Connection." A truly powerful book.

This is a kind of 10th anniversary edition about how the hidden conversations inside our bodies affect our mood, choices, and overall health. And I think science has finally caught up with this simple idea: what happens in your gut affects every system in the body and is linked to almost every disease you can think of -- whether it's depression or dementia, or cancer or heart disease, or diabetes or multiple sclerosis. Everything is somehow connected to the microbiome in the gut. And even a whole new field of dietary psychiatry has emerged since then .

I think systems biology is now coming to the forefront in understanding the body as a complex network of systems, rather than that structured medicine based on organs and specialties that has nothing to do with how the body actually works. This is just the legacy of Vesalius, who dissected the body. So , we're in this situation now: what do we know about the microbiome today? What can we do to properly assess his condition? And how do we actually treat people by focusing on the microbiome? Your work is largely devoted to this in your new book, which is a truly incredible guide.

It's more like a practical guide called the Mayer Model. Optimize your health and well-being through the brain- gut connection. It is already on sale. This is a really great practical application of how we can re- establish our healthy microbiome. So maybe we could start by having you outline the scope of this problem again. How big of a problem is the microbiome for health and chronic disease in 2026 , especially in America? Yes, I would say that, based on what you have elegantly summarized, it would change the way you look at these interacting systems.

So it's not just a microbiome, it's not any specific microorganism. The point is precisely in the system in which these elements interact with each other. I think after the initial enthusiasm... Well, I would say, after the initial skepticism 10 years ago, when the first papers came out about how changes in the microbiome could affect emotional behavior in mice, I was skeptical, because we've been studying the brain-gut connection for decades without the microbiome and we have a pretty good idea of ​​how it works. So I went from my initial skepticism to joining in the general enthusiasm.

This should explain everything, and we could cure all our chronic non-communicable diseases by manipulating the microbiome. But now I've come back to a much more cautious view : we have a lot of evidence from animal studies that there is a cause-and-effect relationship between the action of microbes and the outcome. Unfortunately, we don't have the same evidence for humans. We still have to rely on correlations, epidemiological correlations. So I prefer to remain skeptical about whether we can really overcome our health crisis by focusing solely on the microbiome.

Can we just tell people to take this or that probiotic or synbiotic? I just do n't think it's that simple. And I say this because if you look at reality, there are a lot of people, for example, on the topic of longevity. Many people live to be centenarians, to one hundred years old. If you look at these people, I highly doubt they paid attention to all these things that we do now . No. we promote, from physical exercise to healthy eating . There's also, you know, strong evidence that many of these negative factors, like traumatic stress, changing the microbiome, have such a long-term effect, because many of these centenarians, actually the Holocaust survivors, went through the most intense Ogo.

the most severe stresses in early life, and you know, given a simple model, you would say. So, what can we do? I mean, this goes back to your, your, your, your question. The interventions have n't really changed much, you know, that's one thing I noticed when I was writing this anniversary edition and rereading the book from ten years ago . Um, there really weren't many new, if any, practical recommendations that we could give based on science. We know a lot more about the system now, but the main, most effective interventions are essentially lifestyle and diet.

You know, that, um, it's kind of a paradox, and I don't know if that's going to change or if we'll ever get to , I mean, it's kind of another topic that we can talk about, which I mentioned in the anniversary edition. There's this, this new branch of science about bioengineering probiotics, where you can essentially, you know, interfere with certain functions in the body. Um, we don't have them for clinical use yet. For example, individual probiotics for certain diseases. Yes. Yes, for certain diseases. For example, like one for obesity, another for inflammatory bowel disease, you know.

It is theoretically possible that this will happen. I've been involved in some of these studies related to, um, um, you know, both estrogen recirculation and its use in inflammatory bowel disease. Yes, we're not there yet, and we don't have any clinical trials to prove that it actually works. Yeah, I mean, that's the challenge, that's, you know, what I often say: absence of evidence is not evidence of absence. And I think, you know, the fact that we didn't really have the funding, which is a problem, for a systemic approach to treating gut problems, is a problem.

And that leads to a kind of gap in the scientific literature where there's a whole group of doctors who are using clues in science, because there are a lot of clues, a lot of things that indicate what works and what is helpful. It's prebiotics or probiotics or polyphenols or SIBO treatment or fungal overgrowth or gut repair. I mean, there's a lot, a lot, of a sort, of animal data, there's some human data, but it's not a systematic randomized controlled trial. And this is really just a consequence of our very corrupted scientific paradigm, which is mostly funded by pharmaceutical companies and is geared towards what can be made a lot of money.

But restoring gut health and function isn't something you can make a lot of money doing. Therefore, it is done by a group of doctors in the field of functional medicine. We have a whole system that we developed based on a framework called the 5R program, the essence of which is to reboot the gut. This is the removal of harmful components, such as allergens, pathogenic bacteria, SIBO, or parasites. Replacing what is missing can be digestive enzymes, hydrochloric acid, or prebiotics. Then, of course, reinoculation, that is, adding probiotics.

And, of course, recovery—finding remedies that will help soothe the gut , whether it's vitamin D, vitamin A, omega-3 fatty acids, or other substances like glutamine. And then we help restore the nervous system using relaxation techniques and various methods of rebooting it. This has not been scientifically proven, but it is something that is clinically used by thousands and thousands of patients. And it seems to be working. Even when we don't fully understand what's going on in the microbiome. I've encountered this quite often, for example, I recently had a patient with severe SIBO, bloating, distension, constipation, pain, neurocognitive symptoms, fatigue, and brain fog.

I treated her with three antibiotics because she had hydrogen sulfide, hydrogen, and methane. Then I treated her with herbs to calm everything down after the therapy and gave her microbiome restorers, probiotics, etc. And she feels great. I think for people who suffer from similar problems, and by the way, it's possible to have intestinal problems without experiencing any gastrointestinal symptoms. This is an important topic that I want to talk to you about. But if they do exist, there is usually a way to overcome them. And regular gastroenterology doesn't really focus on that.

So I like your perspective on this and how you plan to bridge that gap. Yes, I find what you just said very interesting. So, if you had talked to me 10 or 15 years ago , I would have said, you know, I don't believe in that. It has to be evidence-based, we have had many breakthroughs in medicine through the traditional model and randomized controlled trials, and in the meantime I have changed my view a bit. Some mornings I feel like I have a lot in common with the functional medicine approach, and I've started getting invited to meetings, which was always surprising at first because I've never been very positive about functional medicine, but the second point is the vast body of historical evidence from ancient healing traditions; If people have been using something like turmeric for thousands of years as an anti-inflammatory , it can't be a mistake.

I mean, people wouldn't be stupid enough to use something that has no effect or benefit at all. And there are many such examples. So this historical evidence for me is also something that I am aware of, as are the flaws of randomized controlled trials, because I have seen it clearly having done many of these studies. Namely, the heterogeneity of people is one of the big problems. You know, you can do a randomized controlled trial in mice with a 100% positive result. Yes. Yes. But people are not genetically identical, they have different backgrounds, different genetics, different microbiomes and different lifestyles, and that is definitely a problem.

I think that's a fundamental flaw in the scientific model that we use, and we're not good at creating an "N of 1" study, which is actually what the NIH calls the highest level of evidence, where you take one person and use them as your own control before and after treatment, measuring change or outcomes—that's a validated measure . We call this anecdotal evidence, but in fact, if conducted systematically, it provides a great deal of information. Yeah, it's quite interesting to me that I've ever , you know, but being an avid scientist, I've always been open to ...I mean, I have my own hypotheses, and if they don't support reality, I abandon them.

I'll move on to a better hypothesis, and that's kind of what happened with the treatment of chronic diseases, you know, our... Yeah. Our paradigms and our reductionist hypotheses simply don't work for them. Bloating, gas, and irregular digestion are often perceived as minor problems, but they can seriously interfere with your quality of life. I see this all the time with patients who experience discomfort after eating, worry about digestion while traveling, or are frustrated that nothing they've tried really works. This is one of the reasons why I continue to recommend Seed.

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My favorite is Sitopia King Salmon, it's rich in bioavailable EPA and DHA, and you get so much of it in one meal that it surpasses what most people get in a week from supplements. And honestly, it tastes a lot better than a pill. So get your first box on sitopia.fish and use the code Hyman for free shipping. So maybe we should have taken a little time to step outside of this reductionist model that we're talking about and step back a little bit to say, "Okay, here's the microbiome." You have been studying it for a long time.

You have done a lot of research in this area. How would you explain to people how the microbiome interacts with the body to cause so many different health problems, and how do we start to think about the Mayer method or the Mayer model, which actually helps people " reboot" their gut? Yes, there is one simple story that I tell patients . You know, there are a lot of beneficial molecules that microbes produce as metabolites from our diet and everything we consume. And there are many compounds that cause inflammation or a weak immune response.

So when I talk about inflammation, I always prefer the term " low immune activation" because you don't get the same inflammation that you get in inflammatory bowel disease. This is not something you will necessarily see during an endoscopy or biopsy. But at the same time, microbes produce these beneficial molecules, and, you know, our knowledge of this is limited right now. So, short-chain fatty acids, mainly butyrate, have anti-inflammatory effects and many other health benefits both at the gut level and throughout the body, as well as in the brain.

So the balance between these harmful substances that enter our system and these anti-inflammatory molecules, I believe, ultimately determines the health of your organ, well, my main interest, the brain. So, theoretically, you could do some unhealthy things and still have all these chemicals in your diet. But if you eat a very varied diet rich in fruits and vegetables, you will produce enough anti-inflammatory molecules that balance these negative effects. So you will never get only a purely positive effect on the brain from your diet. It will always be a mixture.

And I believe that it's all about balance. So, that's one thing. The second explanation is that the microbiome is located at the interface between what we call the exposome—the outside world— and our immune system, microns away from all these immune cells. One mistake in this communication could trigger a deadly inflammatory reaction. It's amazing that this doesn't usually happen, because there are many defense mechanisms. But I think it's worth considering the microbiome as the main " translator" in our body, which translates everything that happens around us, gets into our food and comes to us through the mind, because it also affects microbes.

Microbes translate this information into the body's own language. And if the result of this translation is a pro-inflammatory or neurodegenerative message, then this is where disease arises. So I wouldn't say it's like people always say that the microbiome is just another organ. I like to think of it as a master translator, able to speak the same language as the biological molecules used by our brain, nervous system, immune system, and microbes. I mean, they're all similar, so they all speak the same language. But you need this translation, this intermediate stage, to tell the body how it should react.

So the gut microbiome is almost like a transducer of signals from the outside world to your body, which then changes everything that happens in your physiology. In other words, what you eat, your lifestyle, Yes. toxins, infections— all of these affect your gut microbiome, and it, in turn, affects every biological system in your body, regulating, changing, and modifying it, both through absorbed short-chain fatty acids and microbial metabolites. Stan Geisen of the Cleveland Clinic once asked, “How many metabolites in the blood, of which there are about 6,000, come from the microbiome?” And he replied: "I think a third or a half ." I don't know if this is true or if there is any evidence for this, but is it really so?

This is true, and the problem is that we don't know most of them , except for, for example, TMAO, which Stan Geisen mentioned, or certain tryptophan metabolites such as kynurenine. We don't really know about most of them, or we only know about them in a simplified form. So people would take one of these metabolites, add it to a cell culture to see what would happen, or, say, to a mouse model. But these metabolites don't work that way at all . They all interact with each other.

Here again the concept of systems biology arises. It's a whole network of what you could call potentially harmful metabolites and beneficial metabolites that are constantly interacting and shaping the outcome. And this result in a healthy person is usually always positive, which is simply amazing. I mean, when you consider , you know, what we're consuming and the environmental impacts, particularly microplastics, I'm actually amazed at the sustainability of this system. So, the evolutionary engineers, you know, did a masterful job. This is true. But I think we're really damaging our microbiome in the 21st century.

We are seeing an increase in cesarean sections, a lack of breastfeeding, early antibiotic use, an increase in toxic load, food sensitivities, I mean food additives, emulsifiers, and other substances that destroy the microbiome. And then we get, you know, poor nutrition, lack of fiber, ultra-processed foods, and the list goes on, and stress. And all of this directly affects the microbiome. If I may add, if I may comment, yes, this system has been masterfully designed over millions or billions of years, whatever you call it . The last 100 years have created a mismatch in this system, you know, with microbes that have adapted quickly to all these environmental changes.

Because with their millions of genes, you know, they're much better at it. But our bodies—no, our immune systems couldn't keep up with these changes. Nothing prepared our immune system for what we have today. So now there's this mismatch between the microbial world that has adapted to what we eat and what we feed them, and our much more conservative human biology, so this inflammatory response is essentially a response to the system not recognizing this radically changed microbiome world. Even if it's not necessarily harmful to us, the immune system is alarmed because it sees that there are fewer of these microbes , more pathological molecules, fewer beneficial protective molecules, and yes, I like this concept of mismatch that has emerged over the last 100 years.

In a sense, this is the main problem we face. And how will we deal with this ? Ultimately, I'm not entirely sure . We can try all sorts of things, as we are doing now, but unless we change the environmental situation, which I doubt, it is hard to say what it will look like in 100 years. So, well, we have to take care of our microbiome, and I think there's a real evolution of research right now that's pointing to more specific personalized probiotics, prebiotic products , the role of polyphenols, all these colorful plant compounds that help fertilize the gut, and also fermented foods as a means of impact.

So, there are a lot of things you can do to really take care of your microbiome. I don't think most of us think, "Oh, how do I take care of my microbiome?" They say, "Oh, I'll train for muscle, I'll take care of my sleep and I won't eat too much sugar or anything else for health." But people don't think, "Oh, there's a whole organ there that I really need to pay attention to and that I really need to take care of." So if people have n't thought about it, they should start, and when they do, I'd really like you to talk about your model, the Mayer model, that you've developed, about how to really take care of your microbiome in a microbiome-unfriendly world.

This is the world we live in. So I think, first of all, we have to realize that I have created these pillars that influence healthy longevity and health. And at the center of this flower is the brain-gut- microbiome system -- this complex two-way communication system from the brain to the gut to the microbes and back again, which I think of as the master homeostatic organ in our body system. So the first thing we have to realize, and the second thing is that the influences that are the petals of this flower that determine the end result of homeostasis, have different weights for different people.

It's very personalized. So, these petals, or these influences, are food (one of the most important), exercise, mindfulness, resilience, community, connection, relationships, purpose, and sleep. Therefore, these seven influences have different strengths of action on different individuals. Therefore, in one person, diet can be the cause of 100% of the variance in the final outcome of homeostasis and balance. And for someone else, diet may only play a 20% role; They may eat very unhealthy foods, not exercise, but they have a very strong sense of community— both socially and spiritually—and that makes up for everything else.

So, I think the most important thing is to realize that we are all different in terms of the importance of these influences. So we have to project—each person has to project, has to look at themselves, or their doctor has to look at what model this individual fits into. And then focus on developing those things that, you know, are most important to that person. So would I tell someone who has metabolic syndrome, obesity, doesn't exercise, that it's probably worth working on all of these levers, you know , gradually.

And that's what I, you know, suggest in this book, "The Maya Model," is to do it gradually. There's just no, you know, you don't have to do it , or you can't do it in a week . You have to work on all these challenges gradually. And in the end, you will feel that you have become responsible for your health, your overall resilience, your balance, and you will reduce your risk of developing chronic diseases. So, I mean, the first thing is to adopt the model, this seven- pillar model.

Other people have also proposed similar models. We need to move away from the idea that if you meditate 5 hours a day and do nothing else for your health, it won't help you. You know, monks don't live to be a hundred years old. You know, they usually...I always observed this when I was hiking in the Himalayas. Yes, you don't see people living to be a hundred, that's not their goal anyway, but now our goal is healthy longevity. I mean, society has finally recognized that this is the most important goal for them— healthy longevity without the billions of pharmaceutical products that sustain our lives.

And for that, I believe you need a holistic program. I think functional medicine also offers that, you don't tell someone, "You just need to take one supplement and we'll take care of everything." So, I would say that all of these things will be reflected in changes in the microbiome, which is interesting. So you might wonder why sleep affects the microbiome or a sense of purpose or a sense of community. But studies have shown this. This is reflected in a healthier microbiome, characterized by an overall increased diversity, richness, and increased abundance of anti-inflammatory organisms.

So, that's my biggest discovery in the last 10 years, I think, the shift from the mind-gut connection to this holistic program where the microbiome still plays a central role, but it's kind of an indicator that's a good thing. So, as we do stool tests, and I think we're getting better at interpreting them, I still think we're not where we want to be ultimately to have a measure with predictive value, you know, whether you're at high risk for Alzheimer's when you do it in your 20s or 30s.

But we'll get to that. I think technology is evolving, as is AI, in how to interpret these vast amounts of data that can be obtained from the microbiome. Yes, I would say that the microbiome is a great indicator , better than most other organ components in our body . I mean, it's quite interesting what you're talking about, because you're saying, essentially, you now understand that external influences, our thoughts, our feelings, experiences, all of these things affect the microbiome, exercise, stress, sleep. It's a two-way process, as the microbiome also influences all of these things.

So it's kind of a conversation that's constantly going on between the microbiome and the brain. And, you know, I think, I remember when we were taught in medical school, you're a little older than me, I think, but we learned that irritable bowel syndrome is a functional bowel disorder, and we joked that it was " supertentorial," meaning it was all in your head, and that we identified that people were anxious, and that's why they had this problem. And we kind of blamed them, because, you know, it's your fault.

You are just anxious. That's why you have these digestive symptoms. But I remember an article, I think it was in JAMA many years ago, where they, I forget the name of the scientist, but he talked about a different direction: the enteric nervous system, leaky gut syndrome, dysbiosis and inflammation in the gut sending signals back to the brain when the microbiome is disrupted, causing brain dysfunction. Whether it's mood, behavior, attention issues, or autism spectrum disorders , it's all affected. And that's why I think your model is very important because it works both top-down and bottom-up.

And this, you know, this is kind of , I don't want to use this word " trendy," but if you look at science, it's moving more and more towards, you know, systems biology, and we're doing that in our research as well. I mean analyzing these complex datasets with, you know, neuroimaging data, behavioral metrics, blood metrics, and also, you know, microbiome and diet metrics. You put all of this in one pot and then use sophisticated artificial intelligence techniques to work with this data that the human brain is unable to comprehend in the same way.

So, I think this is happening in many areas—this glut of data that we can generate and collect. But we have not yet been able to best interpret them and create action plans based on individual patterns. So, there may be pattern one in one patient and pattern two in another patient. And there are always attempts to do it in such a simplified way. Like many of my colleagues, we firmly believe that artificial intelligence will make a breakthrough in this. Let's talk about this, because I think what you're talking about is something really important, because there are probably 40 trillion bacterial cells in our gut .

There is probably 100 or more times more bacterial DNA in your gut than your own. They constantly produce proteins and metabolites. There are thousands of metabolites from the microbiome in your blood. This is almost impossible to comprehend. A regular doctor might look at a panel of blood tests. It's, you know, 20, 30, 50, maybe 100 indicators, but when you're talking about thousands, it's just hard to process it all. So you're talking about an era we're entering where AI will help us understand the complexity of human biology.

And I'd really like to hear you talk a little bit more about how this will impact our understanding of the microbiome and how it will impact the clinical practice of medicine in chronic disease and how chronic disease and the microbiome are interconnected. I think this, you know, will fundamentally change the way we look at the microbiome. I still do, although, you know, these stool tests have gotten a lot better, and some companies are using AI to interpret them or contextualize them with published data. But I think, ultimately, we will reach conclusions that go far beyond what we are talking about now.

You know, this whole current approach where we look at microbiome test results, look for abnormalities, and then focus on three or four organisms and create a probiotic or prebiotic cocktail to boost them— I personally think that's going to become a thing of the past. I think we will have “fingerprints”—we will get data on people, compare them to tens of thousands of others, and see that these patterns repeat themselves in different populations, and we will be able to link them to dietary and lifestyle characteristics. I believe this will happen within the next 5 years.

We are facing this ourselves now. We have huge amounts of data, and collecting information is one thing, but effectively running it through this analytical “ mill” is still an unsolved problem. So this will definitely happen. I think that appropriate recommendations will follow. After all, current guidelines often focus only on diet. If you look at the situation with inflammatory bowel disease, a low-fiber diet was initially recommended as beneficial for patients with Crohn's disease. And now we have pretty compelling evidence that the Mediterranean diet is the best anti-inflammatory intervention.

If you don't have stenosis or strictures. Yes. So, I think we will get much more rational recommendations. I also see, for example, at the University of California, Los Angeles, that when a complex IBS patient comes in, they don't just get dietary or probiotic recommendations. He is also undergoing a behavioral evaluation. And if, like many people who end up in a university clinic, there is a strong psychological component—childhood trauma, anxiety disorders, or depression. It depends on the patient group, but in the most severe cases of IBS, the problem cannot be solved by changing the diet or taking antibiotics alone—a holistic approach and involving experienced specialists in these areas are necessary .

Psychologists who specialize in working with the gut, CBT, hypnosis, and adapted specialists. I think it's already changing the system when I look at what happened at UCLA , because when I started there, we first opened a clinic like this, a holistic clinic, but it took a long time. It took almost 40 years before this became an official program of our gastroenterology department, and it is happening at other universities and other institutions as well. So I think we're moving forward, and I shouldn't say it's only important for IBS.

I mean, it's the same situation with inflammatory bowel disease, where we have a lot of people who are not responding well to biologics , where increasing the dose of the drug doesn't help, and we need to identify mechanisms by which the brain is actually stimulating an inflammatory state in the gut in addition to what's going on there. It's a pretty, pretty exciting time for the microbiome, I would say. I think we will learn a lot of new things . I want to dive into the other part of the conversation, which is about longevity and aging and what happens to the microbiome as we age.

And there seems to be some interesting literature on this, and you discussed it in the context of the microbiome , Parkinson's disease, and Alzheimer's disease. The question is, how do we think about the aging microbiome? Is this a sign of aging, that is, a characteristic of the aging process? It seems like this is one of those things that is getting worse. And it appears that this is a risk factor that can be influenced. We've studied exceptionally healthy older adults and centenarians and their microbiomes, and I wonder if they're different.

So maybe you can talk about some aspects of longevity, the aging microbiome, and how we should think about that. Yes, initial studies were conducted on selected population groups, for example, in nursing homes . And it was unclear to what extent the change in the microbiome, the reduction in diversity and richness, is actually a consequence of the dramatically changed lifestyles in these senior homes or nursing homes . Both in terms of diet, especially dieting , and in terms of loss of purpose and loss of social interactions .

But in the meantime, we know that this is only one factor, and many studies of the microbiome in aging have suffered from not controlling for factors other than age. So we know that microbiome diversity is fairly well preserved from middle age to old age. There are changes, of course. When you compare the microbiomes of different people, they become increasingly different. So an increasingly individualized picture is emerging. There is a decrease in the number of certain microbes that play a role, for example, in the metabolism of bile acids in the intestine.

I think we're gradually getting a pretty clear picture of the healthy long-lived, and it's not the simple explanation we gave 10 years ago— just a reduction in diversity, which makes them more susceptible to disease. In reality, everything happens much more subtly. I think there are dramatic changes happening in those factors that we talked about earlier, in those levers that influence the microbiome. Physical activity is obviously significantly reduced in most people. Dietary diversity is reduced unless, of course, you can afford to have 30 different types of plants and vegetables delivered every week.

So this reduction in the diversity and prevalence of beneficial microbes is definitely a risk factor for the occurrence of many diseases that accompany old age. But we must realize that diseases like Alzheimer's and Parkinson's begin at the microbiome level as early as our forties . There is a growing body of research showing that it is possible to predict changes based on negative microbiome readings much earlier in life. So when the functionality of the microbiome declines, disease becomes clinically evident. This is probably a good way to determine where exactly we can intervene.

We can intervene in middle age in high-risk patients who have no symptoms at all , but at the microbiome level we see signs that don't guarantee but indicate high risk. But we can certainly, as soon as the first signs and symptoms of neurological disease appear -- and I was talking specifically about Parkinson's and Alzheimer's -- really aggressively change the processes that are happening within the gut microbiome. I would say that at this age, dieting is likely to be more successful and practical than some other changes.

But social connections and purpose are also important. I mean, all of these things...I think so many older people, you know, we have this epidemic of loneliness, which is definitely reflected at the gut microbiome level, you know, it's quite intriguing. It's like, do you have this mirror inside you? The better we learn to detect subtle changes that reflect environmental influences, the better we can prevent them and aggressively treat them. If you already have advanced disease, I do n't think you need to do a microbiome test. You know, it's not going to change the situation for someone who has advanced Parkinson's disease with all the neurological symptoms.

It won't change, it won't have any impact. The same with Alzheimer's disease. In Alzheimer's disease, it's almost the opposite, you know, you want to... There's evidence that the keto diet is actually beneficial because it has an anti-inflammatory effect on the brain in people with, you know, Yeah, yeah, I've seen that. I have treated Alzheimer's patients using keto diets, and it has been remarkable to watch how it affects them. And I think my question to you now is, as we think about taking care of the microbiome, and the microbiome of aging, it's a contributing factor to accelerated aging by increasing sterile inflammation in the body and affecting all these other systems.

Let's go through the practical steps, since you mentioned 30 plants. I think this is important. I think I want to discuss with you the specifics of what exactly you recommend for people to maintain the health of their microbiome as they age. Yes, it's actually not that different from what I recommend to all my patients. And I mean, it's sometimes even a little embarrassing to admit, you know? So, despite all this sophisticated science that we have, all these subtypes and personalized diets, the approach remains pretty standard, you know, a general approach.

There should be a certain standard concept , for example, 30-35 plants and vegetables, which adapts to taste preferences, because food should bring pleasure. An important function of food for our health is enjoyment and satisfaction. This is closely related to sensory perception in the brain. So, I would, I would say, you know, start with a breakfast that has a lot of ingredients: um, seeds, um, oatmeal and, um, yeah, chia seeds , fruit, um, fermented foods, so you can easily find five to ten ingredients to add a spoonful to your morning bowl, instead of just eating yogurt with blueberries.

Me, I think now more than ever it's important to avoid ultra-processed foods, you know, eliminate them from your diet. I often say that food is medicine, but there's another part of the conversation that we don't talk about enough. How we prepare food also matters. The warmer months are actually a great time to change your habits. People are cooking more fresh meals, grilling, eating lighter, focusing on feeling better every day. And one small but significant upgrade is to pay attention to the dishes you use regularly. I was impressed with the Made In stainless steel collection because it is designed without chemical coatings and built for durability, heat control, and everyday cooking.

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I have also noticed that many people experience fewer food cravings when they take it in the morning because their bodies are finally getting the amino acids they need. Go to bodyhealth.com and use the code Hyman20 to get 20% off your first order. This is bodyhealth.com and the Hyman code is 20. And the reason is that there is scientific evidence that it is harmful to your microbiome. So, if, you know, 60% of our diet is ultra-processed food, it directly harms our microbiome and causes what's called "leaky gut" due to emulsifiers and other additives.

So, it's ... you know, it's not that artificial sweeteners don't affect the microbiome. People think, "Oh, it doesn't matter," but it's actually so important that I think if there's one thing people can do , it's replace ultra-processed foods with real foods and eat a lot of plants, right? Yes, and to make it practical, you can make salads—not the typical lettuce salads that, you know, have a bad reputation right now because of these, well, infectious diseases. Cyclosporosis. We experimented with this at home. You can easily add 10 different vegetables to a salad, into a complex salad, which.

So if you start your morning like this and , um, end your day with a salad, you've actually already met that criterion and are avoiding ultra-processed foods , especially, you know, sweets. I mean, we still don't know for sure about ultra-processed foods . I mean, there's a debate about this concept, that it's too vague, and some say it's just the sugar, but it's definitely not just the sugar, because No, no. Mmm, like all these chemicals, I don't even know what they are. They are printed on the label.

This is kind of strange. Like, for example, on the plane you look at these, well, so-called pretzels. Pretzels are just a small part of it. And every small package, if it doesn't contain simple ingredients that you recognize, definitely won't do you any good. Hmm, do you pay much attention to prebiotic products for humans? Because I think there's more and more evidence about prebiotics and polyphenols than probiotics as being beneficial, because it really changes the composition of your microbiome over time. Whereas probiotics simply provide something extra, but they don't really affect the formation of microorganisms that grow there.

Yeah, and coming back to that, I mean those 30, you know, fruits and vegetables. So, most vegetables and, I mean , some fruits as well, fiber is, of course, a very important component, a component that promotes health. Because microbes are masters, they love fiber because they break it down into their own basic food source. But they also convert it, for example, back into these short-chain fatty acids. From a lot of fruits you get polyphenols , and that's a group that, you know, I would say, has been misnamed or mischaracterized, calling them antioxidants, because Mgm.

They are an interesting part of our diet, just like fiber. Yes. It's not absorbed in the small intestine, um, the molecules are too big, so they need to be broken down. The same goes for polyphenols: they are broken down in the gut by the microbiome into smaller molecules, which are then both food for microbes and absorbed as health-beneficial phenols and phenolic compounds that circulate in the body. So there are some really good studies, and people always forget that, you know, with some of the polyphenols, like flavonols, for example, the studies go all the way down to the molecular level, um, showing that they , you know, promote vasodilation of the small blood vessels in both the heart and the brain, um, increase the production of nitric oxide, um, which is a vasodilator, um, and so we know the mechanism of how they actually protect these organs, both the brain and the heart, and we have clinical outcome data from fairly well-designed clinical trials.

So this is an exception, you know, that... I think this is often, this is often glossed over when people say, " Yes, antioxidants." Yes, it's good to have antioxidants. This, this is something much more than this, you know, this Yes, I call them biological response modifiers. They're essentially signals or chemical signals that regulate all sorts of systems in your body, and I think we evolved with all these plants to do all of that for us, especially our microbiome. And you know, we, we have to feed ourselves, but we also have to feed the microbiome, and I think the emphasis is on more prebiotic foods, more fermented foods, more polyphenols.

These, these are things that are different than just taking probiotics that I think people could really learn about, and I think you could probably cover that in your book, right? Mayer's model and talk about these different aspects of how to optimize your diet for your microbiome. Yeah, you know, I always emphasize this point, you know, it's actually pretty easy to find the right diet. If you find a diet that's good for your microbes, for their diversity, health, and abundance, that's going to be the best diet for you, too, because we've been living with these organisms for, you know, millions of years.

Our ancestors, you know, even prehuman ancestors, did the same thing. So you always say that the general advice is to eat what's best for your microbes. And, um, the two main categories that come up are, of course, fiber, prebiotics, and, um, polyphenols. I mean, there are many other vitamins and minerals that can be added, but the main "workhorses " are these three groups of ingredients. So, it's fiber, polyphenols, and prebiotics. I didn't quite understand about the third point. It was prebiotics and polyphenols, and what was the third?

Yeah, I mean, the third thing I recommend for the diet is, you know, naturally fermented foods. And the reason I say this is because people always say, "So, when did people start eating yogurt?" . But our ancestors fermented foods for millennia to preserve them, not for their own health. So our immune system and, you know, our gut has had enough time to genetically adapt to these fermented foods. Again , the greater the variety of these fermented components, the better, we believe. I mean, diversity is always a key component in recommendations.

It's not just about what you eat, but how varied your diet is and how often you eat it. Yes, and I think that to be more specific, there are many specific foods that are beneficial to consume. And, you know, I try to cook them and eat them regularly. These include, for example, garlic, onions, shallots, leeks—great prebiotic foods , asparagus, dandelion greens, beans, lentils, chickpeas, oats , barley, boiled cooled potatoes, cooled rice or pasta, which creates more resistant starch, and green bananas. There are a whole bunch of products that are really great.

I think there are also polyphenols, for example, cranberry, pomegranate, green tea, and many colorful compounds that help a lot. And I have personally used them to help my own microbiome, and I see changes. Have you had your microbiome tested? I'm sure you've had a lot of microbiome tests done on your stool sample? Yes, yes. Oh, yes. I've been testing them, and they definitely change and adjust depending on what I eat and my overall health. So, you know, it's hard to actually change your microbiome with probiotics alone, but if you're consuming fermented foods, prebiotics, and polyphenols, you're actually growing a better "garden" in your gut.

And I think that's something to think about when you're choosing what to eat—it's very inspiring. Use scientific data about what your microbiome likes to feed not only yourself, but it too. And this, you know, is not higher mathematics at all. It's actually quite simple. Once you accept this concept, it becomes clear that there is nothing complicated about it . This should be enjoyable. I always emphasize this: if you go to Mediterranean countries, you can see how much they love their food . They don't eat it because it's healthy, you know, they...

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Go to bioptimizers.com/hyman and use the code Hyman to save 15% on your order. That's right. It's simple. And if you eat like this , you can cook delicious food. I'm just thinking about being more conscious. Um, and also just being aware of all the things that are bad for your microbiome. And I think it's important to realize that consuming ultra-processed foods , taking many different medications, and being exposed to environmental toxins—all of these things affect your microbiome. Stress, your relationships, your connections, the amount of exercise, everything you talked about in the MAYER model; all of these change the microbiome in one way or another.

And the levers of influence exist. Um, I guess I'd like to close by asking you: This is kind of a general conversation about creating a healthy microbiome. But I see it as a target, a very, very specific target for treating many medical conditions, using the microbiome as a direct route to many health problems, whether it's autoimmune diseases, allergies, asthma, fibromyalgia, or even migraines, or what you talked about, strobolom, which is estrogen metabolism in the microbiome. We didn't go into it too much, but it affects female hormones.

Therefore, treating the gut can often be the key to solving many different problems in many different areas of medicine. And I'm curious what you think about this and where the evidence is now on this. This is impressive. I'm still amazed by this, and as a doctor and a scientist, it's not my place to say that this is some kind of " string theory" of health and diet that explains everything. But I think the microbiome has this property that you could use it as...and I keep emphasizing the connections between the brain and the gut.

I mean, the gut is an amazing organ. It has all these components: the immune, hormonal, and nervous system component. And microbes know exactly how to communicate with these systems in our gut. So, uh, I would say, um, it does n't surprise me that it has such a big impact, especially on the immune system, when you consider that almost all immune cells pass through the gut and reach their distant destinations. As it was during COVID, you know, COVID doesn't start in the gut, but the immune cells that are in your lungs have a connection to the past when they passed through the gut immune system .

And the same goes for the brain. So many cells that enter the brain have a history of interacting with the microbiome. Um, I, I, I, I think, you know, we have to be careful not to make simplistic conclusions, like, now we know everything, but I think we have to admit: we have unexpectedly discovered a system in our body that almost rivals the brain in its complexity and influence on It's like . I mean, we're in a new era in medicine right now. I think the microbiome has to some extent shaken up some of the fundamental tenets of traditional medicine, which is focused on specializations and organs, and now we understand how the gut is connected to every system in the body, that the body is a network and the microbiome is part of it, so we have to think about network and systems approaches to treating disease, not this reductionist model.

And I think, you know, in my years as a physician, I've found that when I focus on gut health in people with different diseases, whether it's Parkinson's, allergies, migraines, PMS, or anything else, like autoimmune diseases, people get better. People are really improving their condition. And you know, I see this over and over again, and it's pretty impressive. And I think the methods are still being developed and we're just at the beginning of this era, but that doesn't mean we can't apply these principles clinically and practically because they tend to be very low risk.

They are very, very often effective. You know, there are no particular downsides to eating healthier, controlling certain things, using prebiotics and probiotics. This is a fairly low risk, and the payoff is quite high. So, I think this is a pretty exciting moment. So, how do you see this area developing over the next 10 years and its rapid growth? I believe we are in for bigger breakthroughs in terms of practical applications than those that have occurred in the last 10 years. Aha. I think science is still accelerating.

I think the professional acceptance, that is, you see the growth in popularity of functional medicine, even among traditionally trained doctors, is constantly increasing for this very reason. And so I think we have very serious challenges ahead. You know, we're going to face the fact that the next 10 years... it's hard to imagine what this world is going to look like because of all these multi-crises that we're going through, which are also going to affect food production , environmental impacts, heat, and other things. But I think there's going to be a new era of holistic, you know, I have to use this old-fashioned term, but holistic medicine—a medical practice that takes into account all this knowledge that comes from understanding and integrating all this diverse information.

I hope that people, you know, we see some efforts adapting with the MAHA movement. This is something that could not have been expected 10 years ago, that something like this could happen. What, excuse me, what kind of movement is this? MAHA, M A H A. MAHA, MAHA, yes. Yes, yes, Make America Happy Again. Of course. In my opinion, this is not enough, you know, there are still many gaps that will not give what...But this is certainly something that could happen. Imagine what will happen in the next 10 years, you know, but...

Yes, it's true. This is an exciting time with the convergence of systems medicine with artificial intelligence, with changes in health policy, and people's realization that we are living in a different era. I find it quite fascinating, and I think your work is a key part of that, and you really make a huge contribution to the industry. I definitely advise all listeners to buy your first book—the updated edition of The Mind-Gut Connection . And also a new book, "The Mayer Model," which can be found where you usually buy books.

And the Mayer Model is really about practical application. A great book, well designed and easy to use. I think it covers seven fundamentals that really help your microbiome: nutrition, exercise, mindfulness, resilience, community, purpose, and sleep. And it's about how to focus on a proper diet —we discussed very specific things in even more detail. I think this will help everyone listening to develop a healthier microbiome , which is key to feeling good. I think many ancient healing systems understood this a long time ago, but we in the West are finally coming to it too.

So thank you very much for your work, your contribution, and your new book. And I'm looking forward to what happens in the next 10 years. Thank you for inviting me, I really appreciate it. Mark, if you liked the previous video, you'll like the next one. Check it out here.

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