Don't Wait for Alzheimer's — A Neurologist's 30-Year Plan to Protect Your Brain

26:27You can get there from mold exposure, from having insulin resistance, from head trauma, from exposure to environmental toxins, from PM2.5s in the air that we breathe, which is certainly very important right now vis-a-vis the incredible fires that we're seeing across North America. and you're right. And when we target the mitochondria, we get responses like you've described and I have seen and certainly Dale Bredesen has described as well.

26:56Dr. Mark Hyman:Well, there was something really new that you said in your book that I thought was so striking that I hadn't really thought about before, which is that the microglia basically are the immune cells in your brain and they have mitochondria. And I never thought of how the mitochondria in the immune cells affect the function and health of the immune cells. And that was kind of an aha for me. Like, wait a minute, the metabolism, aka mitochondria, of the immune cells, when it goes awry, is what's causing so much of the brain inflammation and the brain on fire that you've talked about for so long. And that's contributing to all these neurodegenerative and neuropsychiatric disorders.

27:36Dr. Mark Hyman:Is that right? Immunometabolism. What a term. So talk about this. I think this is a new idea. I mean, Jeff Landis talked about it, one of our friends and mentors, but like, tell us about what is this? And is this kind of a new idea? And how do we start to think about it? How do we start to act on it and even diagnose it? It's important because it's certainly not just these microglial cells in the brain, but it's immune cells throughout the body that are dysregulated when their metabolism goes awry. And let me make one point that I think is really important. This is bidirectional, that when these immune cells are targeted by glycated proteins, elevated blood sugar, toxins, inflammatory cytokines, it will then shift their metabolism.

28:23It will reduce their mitochondrial function. At the same time, as mentioned a moment ago, when mitochondrial function is challenged for other reasons, then the immune cell will be targeted as well and shift to being less supportive. So it's a bidirectional support system. Immunometabolism support, you know, it goes both directions. And the manifestations of dysregulated metabolism of our immune cell is seen throughout the body. But the central and pivotal role as it relates to the brain, I think, is so powerful because we can influence it deeply by targeting metabolism, targeting the things that I mentioned, the markers of metabolism that we can easily measure.

29:08When we do that, we are absolutely targeting our brain's immune cells, these microglial cells, to be back on our side and back to being supportive. And as we've talked about, this is the upstream mechanism well above the accumulation of alpha-synuclein or beta-amyloid or other proteins that people tend to want to focus on, even phosphorylated tau. The phosphorylation of tau happens, which is, for your viewers, phosphorylated tau, P-tau-217, which is a blood test you can get, you know, doing function health, for example, you can go and get your P-tau-217 measured, is a very valuable indicator of loss of synapses.

29:51If you really want to know what it's telling you the higher the level of this P-tau-217A blood test that is an indication of loss of synapses. It is therefore, and what is causing loss of the synapses, activation of the microglial cells. So this is a very important, and now arguably a more specific blood test, you know, in distinction, a contradiction to the simpler blood test that you and I talked about earlier. so in a very real sense you're you're evaluating what the heck's going on in your brain's immune system when you look at that test but as i mentioned earlier it can be as simple as measuring

30:33Dr. Mark Hyman:your waist to hip ratio yeah i think that's important let's kind of double down on this because i think this is a really this is really new information for people which is up till now we didn't really have a good way of like checking your blood sugar of your brain in other words what is your like your diabetes oh my blood sugar is high i've got diabetes or my blood pressure is I've got hypopressure, but we didn't have a biomarker or a set of biomarkers that we could look at that would be impacted by lifestyle. You know, we could check your APOE4 gene, which gives you a risk of Alzheimer's, but those are genes that can't be changed.

31:04Dr. Mark Hyman:You can change the expression of them. But now we have biomarkers that are really revolutionary, I think. It gives us an opportunity to start to look at people's blood work very early and see what are the progressions and what are the changes and how do we modify those? because it's not just finding this lab work and going, oh shit, I got this problem. It's like, oh wow, I have this problem. My blood sugar is a little high. Maybe I should stop eating bread and sugar. Maybe my P-Tau 217 is high. Maybe I should change my lifestyle. Maybe I should eat better. Maybe I should reduce my insulin resistance so I can improve my metabolic health.

31:41Dr. Mark Hyman:Maybe I should look at my microbiome and help that. Maybe I should look at my toxic load and things that might be triggering this. Maybe I should exercise more. Maybe I should focus on my sleep a little better. Maybe I should think about nutrients I could take that would help my mitochondria or help my regulate my immune system or my microbiome. So it gives you an opportunity to think about creating a plan for yourself that's very proactive instead of reactive. I mean, by the time you are in end-stage Alzheimer's, there's not a whole lot you can do. But early on, you can see a lot of things changing.

32:11Dr. Mark Hyman:And I've been actually using these tests. And in Function Health, we now offer a full suite of tests that include, as your basic panel, a lot of things you were mentioning, insulin resistance markers, insulin A1C, particle size, hormone levels, toxin levels, nutritional levels, homocysteine, all the things you'd want to look at as a foundation. But we also offer an advanced sort of brain panel, which allows us to look at P-Tau-217, amyloid AD-4240, looking at neurofilament light chain, which is often, you know, damaged when the brain's damaged from traumatic vein injury and other injuries, and GFAP, which is another protein.

32:47Dr. Mark Hyman:So there's a lot of things you can look at. And so I think, for me, it's a really empowering moment in neurology. And I mean, I'm going to make fun of you, you're a neurologist, but the joke we had about neurologists in medical school was diagnose and adios. Basically, you would be great at diagnosing things, but there was nothing you could do about it. It is so true. And now it's not like diagnose and adios, it's diagnose and hola, como estas? Let's go. Well, for me, it's it's I want to be interventional long before we diagnose. And, you know, I think what you just described is really fundamentally important that the the standard of approach in medicine has been to treat illness once it has manifested.

33:31And what you're describing is the the approach of keeping people healthy in the first place, which is more valuable. I mean, I would submit it's absolutely the latter. And, you know, we describe our healthcare system in America. It's nothing to do with health. It's treating illness. And so this is very much preemptive, preventive approach that you were describing. And it's very, very empowering. And I remember back in the day, this thought came to mind again. Early on in the PSA blood test, prostate-specific antigen, insurance wouldn't cover it unless you had a diagnosis of prostate cancer. Early on in the PSA, before your time, Sonny Boy.

34:14But anyway, and I thought, how ridiculous is this? And then there was a notion of breast cancer prevention and, you know, wear the pink ribbon, all this. And breast cancer prevention was really emphasizing the way to prevent breast cancer is to let women get mammograms all over the place, you know, every year have, or whatever the interval was, have a mammogram. Mammograms don't prevent breast cancer, excuse me. They early detect breast cancer. So I think that what you're describing, and in fact, that suite of blood tests that you described, you know, the glial fibrillator, the GFAP, the neurofilament light NFL, the looking at phosphorylated p-tal 217, We describe them in the book because they're available to people and they do give you a sense as to where you begin the process.

35:05And, you know, people talk about, well, what about your genetics? And what if I do carry the APOE4 allele? And I know, therefore, if I'm heterozygous, I have a five-fold increased risk. If I have two of them homozygous, my risk for Alzheimer's may increase 12-fold. Should people even know that? And my answer is you bet 100 % because that will be much more encouragement for you to do what Mark Hyman and I are talking about today. And that is get busy and get your metabolism, get your metabolic house in order, and you can absolutely rewrite your destiny. And that's what this is all about. And does it fly in the face of modern medicine, how medicine is practiced here in America?

35:51Yes, indeed, it does. I mean, you know, we see how the deck is stacked, and that's okay. I mean, Robert Kennedy Sr. once said, some people see things as they are and ask why. That's what we're doing right now. Others see things as they could be and simply ask why not. And that's what we're doing as well. Why not? Why not give people the tools to set the stage for a healthy brain now and not have to suddenly awaken at age, at my age, 71, and notice some cognitive issues and then hope for a cure. Do I hope for a cure, a pharmaceutical cure for Alzheimer's? 100%. If that existed, if GLP-1s turn out to be effective, I'm going to sign up for that.

36:36You bet. I will be recommending that. And I talk about that in the book. My mission is not to really think outside of the box. It's really to make the box more inclusive. And I am open to a drug intervention. You bet I am. And having mentioned GLP-1s, I think there is some promise there. But for now, let's do the metabolic work.

36:58Dr. Mark Hyman:Yeah, I think it's so important. And the name of your book is So Important, Brain Defenders, because it talks about how do we defend our brain? What are the things we can do to defend our brain? And right now, I think people don't really know. They know I shouldn't smoke and I should manage my blood pressure and I should not eat too much saturated fat and I should exercise to prevent myself from getting a heart attack. But if you ask people, what should I do to prevent getting Alzheimer's, it would be pretty much a black box for people. So I'd love to sort of spend a bunch of time now. Pretty much what you just said.

37:29Dr. Mark Hyman:Go ahead. Well, it's those things too, yes. The good news is anything treats everything. It's kind of a joke. But if you look at the fundamental reasons we get sick, there's only a few. It's what we eat. It's our lack of activity. It's stress. It's lack of sleep or poor sleep. It's environmental toxins. It's changing our microbiome. It's our genes combined with all those things to determine who we are. And those things are highly modifiable. And we can't change our genes, but we can change the expression of those genes. So let's talk about the fundamental things that people can do other than looking at these causes, right?

38:09Dr. Mark Hyman:looking at the blood tests, which helps you see where you are, what are the things that people should be doing to help their immunometabolism, to help their brain immune system, to help their metabolic health, both with their body and their brain? Because I mean, the brain and the body are the same. Like, it's not like we have, we talk about the body, mind, mind, body. That's just one thing. It's not like two things. So I think that we kind of get all confused about that. But I think we really need to think about, you know, what are those things that people can do very practically that had the most impact on the brain.

38:39Dr. Mark Hyman:And maybe you kind of walk us through what you discovered around how to optimize immunometabolism related to the brain. You bet. And again, so many things came to mind in that setup. And first, back in the day, there was a HeartSmart diet. Remember the HeartSmart diet? As if, well, I don't have heart disease. I have another situation, so I shouldn't go on that diet. No, it's a body systemic, good diet to be on because it's involved with keeping blood sugar where it needs to be and lowering inflammation. And those are the keys. Those are the keys for brain health too, when we talk about diet. But the big, number one, most important thing is to embrace the idea again, that you are in charge, that your decisions matter in terms of your brain's destiny.

39:26All right. Now, where are those, what are the decisions? And I'm not going to rank them, but I'll just go through them. Let's first talk about exercise. You know, when we look at the data that looks at levels of, let me preface this by a study appearing in the Lancet in 2024 that looked at 14 modifiable factors and indicated that attention to these 14 modifiable factors is associated with about a 50 % reduced risk for developing dementia. And by and large, these modifiable factors are of the things we've already talked about that affect metabolism. Interestingly, as a kind of a sidelight, they did not mention diet.

40:10They did not mention nutrition. So I, along with Dr. Robert Lustig, wrote a letter to the editor saying, hey, you know, it must have been an oversight. Here are the references that describe diet, you know, the mind diet, various diets, intervention Mediterranean and their effects on Alzheimer's risk. And we got a letter back from Lancet saying, well, thank you very much, but we're not going to publish your letter to the editor. So I don't know what's going on with that. We'll leave that. But let's first talk about exercise. So, you know, the data that relates regular exercise with reduced risk of cognitive decline is vast.

40:51And, you know, that really came to us in actually the late 1980s from a Dr. Kirk Erickson, who randomized a group of just over 100 individuals. One group stretched, one group aerobically exercised. After one year, he did two things. He did a cognitive assessment, and he actually did three things. He measured their BDNF. We'll talk about that in a minute. And he actually measured the size, using an MRI, of their memory center in the brain. He was first to demonstrate that this intervention, this program that you put people on, was associated with an increase in size of the brain's memory center, a preservation, in fact, an improvement of cognitive function just because these people exercise.

41:38The epidemiological studies looking at people based on their self-reported exercise has shown strong relationship to reduction with more exercise of risk of cognitive decline. And as we look at interventional trials, your friend Rudolph Tanzi at Harvard, along with Dean Ornish, published a study last year demonstrating an interventional trial on 51 individuals, not a huge trial, over a 20-week period of time, demonstrating that when they changed people's diets, allowed them to exercise regularly or invited them to exercise regularly, reduced their stress, these are individuals with Alzheimer's disease diagnosed, that their cognitive function didn't slow in its decline.

42:31By and large, it stopped declining completely.

42:34Dr. Mark Hyman:That's crazy. And in fact, this is in 70 % of their interventional people. In many of them, it actually improved. I'm going to let that one hang for just a minute. So, you know, getting back to exercise, the question I think that you and I are often asked is, okay, I get that being sedentary is bad for my brain, but, you know, sitting around, not doing things. And it's important exercise. One question is, well, what's better then for my brain? Is it aerobic or is it resistance? Is it, you know, the weightlifting or the bands or whatever machine you might use at the gym, or aerobics. And that was actually looked at in a journal called Clinical and Health Psychology in 2025.

43:18A study that looked at, was a review of 36 interventional trials where they put people on these programs, and it was close to 6 ,000 individuals. And their conclusion was, is it aerobics? Is it resistance training? Their conclusion was, it is both. It's the combination that seems to work best. And, you know, as you and I know these types of interventions work a little bit differently. That when we do resistance training, we're building muscles, which is really important because muscle tissue is an endocrine gland secreting various chemicals that ultimately positively influence brain health. So the muscles make chemicals that go elsewhere in the body.

43:59Therefore, it's an endocrine gland more involved in regulating metabolism. The aerobic part of the story improves blood supply, improves insulin functionality. So it's the combination. And what Zhang and the other researchers in that report noticed was that the best bang for the buck, in other words, the best response was in individuals who were 65 or older, you and me, and also those individuals already had some cognitive impairment. Yeah. For brain preservation, cognitive preservation, and even as a therapeutic intervention, exercise is really, you know, one of the fundamental legs of the stool.

44:45Dr. Mark Hyman:Great. Well, I worked out in the gym this morning at seven and I went for a hike up the mountain. So like I got my exercise in, my brain feels good. During the summer when I'm moving between work and everything else, life throws at me. I noticed pretty quickly which clothes actually stay comfortable and which ones don't. That's exactly why I've been wearing Cozy Earth all day tea so much lately. It's made with viscose from bamboo and still feels great even after a busy day. I've noticed the same attention to quality with their pajamas and their sheets too. Everything from Cozy Earth just feels lighter and more comfortable.

45:16Dr. Mark Hyman:And honestly, when something feels good enough that you stop thinking about it completely, you realize how much those small daily comforts actually matter. Now this summer, Cozy Earth all day tea and rib knit pajama set have become two of my favorites. Find yours at CozyEarth.com and receive 20 % off.

45:59Dr. Mark Hyman:more than a decade of development, and the product itself is simple. One active ingredient, C15, that strengthens your cells to support healthy aging. Don't take my word for it. Look at the science. It's all published at discoverc15.com. And that's what convinced me to take it every day. And that's what will convince you too, I think. Head to fatty15.com or slash hymen today and use the code hymen for 15 % off your 90-day subscription starter kit. So, David, let's talk about a few other things around diet and what is so crucial to understand for people as they bring a healthy diet. And I think we've talked about this a lot, but I think it would be good to just crystallize your thinking about this in 2026.

46:39What I endeavor to do in Brain Defenders is simplify because as you well know, there are so many diets out there, whether it's Mediterranean, Mediterranean Plus, added greens, the mind diet, diets named after people, paleo, primal, whatever it may be. And I wanted to look upon diet, not so much in terms of what you should be eating day in and day out by being prescriptive about that, but rather what is the effect of the diet that you choose, but with some stipulations. And I think most importantly, it's a diet that's going to control your blood sugar. And I will say that we've got to get some metrics here.

47:18And I'm all in favor of wearing a continuous glucose monitor, not all the time, but from time to time to get a sense as to what is this diet I have chosen for myself doing in terms of controlling my blood sugar, because my blood sugar is fundamental in terms of controlling my microglial cells and therefore charting my brain's destiny. So get a sense as to the foods you're eating, make choices that are reflecting a better control of your blood sugar. That said, I like a more plant-based diet. It doesn't have to be fully plant-based, but a diet that is colorful, meaning a lot of different colors of fruits and vegetables on the plate, giving you the polyphenols, giving you, importantly, the dietary fiber, that fat we describe should be healthful fat, not fat that is threatening to your body, to your brain, as if the brain were not part of your body.

48:16So I really did my best to simplify. We talk about why it's good not to eat later in the evening, to increase that window of fasting, and all of the things that people are very familiar with. But it's the outcome that is measurable of your dietary choices that I think the outcome doesn't get as much attention as it needs. And that's what I focused on in this book.

48:38Dr. Mark Hyman:Yeah, and also I think one of the things that people are understanding now about neurodegenerative disease in general, whether it's Alzheimer's or Parkinson's or even things like MS, they're often related to changes in the microbiome and gut dysfunction. And maybe you could kind of talk about that because you wrote a whole book about that, but I think it's worth sort of double-clicking on that again for people to understand how important keeping your microbiome healthy is because that's what's determining a lot of inflammation. You're just in making control and affecting some resistance. if there's bugs in there that are not friendly bugs, it can affect you by producing toxic metabolites that affect the brain.

49:20Dr. Mark Hyman:So can you kind of talk about a little bit about the microbiome and the brain in that context? You bet. And you're right. You know, I wrote a book years ago called Brain Maker. And to be fair, some of my colleagues were not, you know, the eyebrows went up. What do you mean, you know, the microbiome affecting the brain? That's the gut. That's, you know, the brain's in Chicago, and the gut is somewhere south of Los Angeles. So, yeah, it was an interesting time. But now I think the mechanisms have been, you know, much more fully fleshed out, delineated, that we can understand, you know, the fundamental relationship between what's going on in the gut, even beyond the microbiome.

50:00But let's just talk about that for a moment. So I think one of the fundamental tasks of the microbiome, aside from the metabolites that these bacteria and other organisms produce is maintenance of the lining of the gut. And as my friend Mark Hyman used to say, probably still says, you know, it's the garbage dump in the gut. That's the term you use. And things should stay in the gut that remain in the garbage. They shouldn't make their way into systemic circulation. Remember, you used to say that. I probably did at some point. No, I think I remember when you did say that. But the point is that there's a lot of stuff in the gut that needs to remain there.

50:36And it stays there because we have really good protection. We have a strong barrier that keeps that stuff from making its way into the systemic circulation. The maintenance of that barrier is predicated on diversity and good functionality of our microbes in the gut called the microbiome. When that is challenged by any number of issues that we can discuss, then they are less able to do that job, less able to maintain that barrier function things get out from the gut into the systemic circulation and even into the gut lining, the outside of the gut, and challenge immune cells. What do these immune cells do now that they are challenged with various chemicals like LPS?

51:19People may have heard of that, lipovolosaccharide. They increase their production of these inflammatory cytokines. If we go back to our original conversation early in this interview, we remember that cytokines, these inflammatory chemicals, make their way to the brain and stimulate our microglial cells to shift from being supportive brain defenders to being destructive. That connects an awful lot of dots between the microbiome being changed and ultimately paving the way for Alzheimer's, Parkinson's, other neurodegenerative conditions. To the extent that there is now

52:01publications allowing us to recognize that we can almost fingerprint the gut microbiome and relate it to risk for neurodegenerative conditions of very specific types. That's how far we've come in studying the makeup of the organisms and more importantly, what they are producing. In other words, the technical term is the metabolomics of what is going on in the gut. But let me just extend this a little bit further. The most powerful influence on the makeup and functionality of the microbiome are the foods that we choose to eat. So now we've added one more dot, one more step, fundamentally relating our food choices to our brain's destiny.

52:47Now, it's through now the lens of the microbiome that you teed up so eloquently. And having said that, it then allows us to understand why it is one nuance of the clear and present threat posed by our consumption, widespread consumption of these ultra processed foods. We live in a country where in adults, 60 percent of calories are coming from these frankenfoods, the term you've used in the past. these ultra-processed foods that represent a clear and present danger to your brain's destiny. Consumption of these foods, one study that was published in the Journal of Prevention of Alzheimer's. Can you imagine a Journal of Prevention of Alzheimer's?

53:34Be still my beating heart. And this study that came out last year followed a group of 1 ,111 individuals over a period of 12.7 years. and basically asked these folks, during this 12.7 year, during the period of time that we're going to study you, what do you eat? So they kept a food frequency diary. What did they find? They found that those individuals who consumed as an average one serving per day of ultra-processed foods experienced a 13 % increased risk of Alzheimer's disease, a disease -

54:10Dr. Mark Hyman:Just one serving. That's not much. That's a handful of chips. That's a 13 % increase of Alzheimer's disease for which there is no pharmaceutical treatment available, as you and I have this conversation. Further, they found that in those individuals who consumed 10 or more servings of ultra-processed foods a day, now that's in the context of a country where 60 % of our calories is coming from this food. So that's not out of, that's 10 hand servings of chips. That's probably on the low end. Yeah. Their risk is increased 270%. That's of a disease for which we have no meaningful pharmaceutical treatment.

54:55270%. Yeah. Basically a threefold increased risk of getting Alzheimer's, which if you live to be age 85, as mentioned, is already a flip of a coin. Now you've really tipped the scales out of your favor. And that's just based on food choices. And so what do the ultra processed foods do? They threaten blood sugar regulation. They threaten insulin functionality. They are pro inflammatory and they mess up your microbiome. These are the discussion we just had. We know that's bad when, you know, the microbiome is threatened back to that. It's not only the gut permeability issue, but it's the lack of production of certain metabolites products of these bacteria that make their way to the brain.

55:38These short chain fatty acids that are important for gene expression regulation. What did I just say? That our gut bacteria are regulating our gene expression, our life code. I better take good care of my gut bacteria because they have a big, they have a very important job. They are determining gene expression throughout my body. And yes, even in my brain for crying out loud. So, so yeah, food matters.

56:04Dr. Mark Hyman:I think you're, you're, you're saying it's so important and people don't realize how, how just dramatic diet can be in prevention and also treatment. And, and, you know, you've written a lot about it. I've written a lot about it. I think one of the things that I think would be really worth sort of diving into a little bit is, is something that people don't really think about that much, which is how do we, how do we think about the immunometabolic effect of toxins? and they're ubiquitous and they're everywhere. We're exposed to so many of them. And yet many of us don't really have a way of sort of understanding how to diagnose them or treat them.

56:40Dr. Mark Hyman:And we feel a little bit confused. It's like, well, what do we do? And I think you and I have both been involved in this field. And I think that having a understanding of how to assess environmental toxic load, how it affects the brain, how it affects metabolism, how it affects immune function is really important. And I think that was one of the biggest ahas I had early on was that toxins can be directly poisonous, but they can also be immunotoxic. In other words, they can trigger immune dysfunction. And there's a whole phenomenon of autogens, which are autoimmune-inducing toxins. The same can be true for the brain, I think.

57:14Dr. Mark Hyman:So maybe you can sort of help us understand that a little bit. Well, you know, we don't put this microglial activation in the category of classic autoimmunity, but in a very real sense, it is. These microglia are activated and then go about destroying our own tissue. So in a very real sense, I think it's fair to indicate that this is, you know, it's not a classic description, but it is an autoimmune situation. I think back to your question though, how does toxic exposure relate to this? And I think in a word, fundamentally. So I don't know how deep you want to go, but whichever toxin comes to mind, I think let's look at toxins that are directly affecting the mitochondria.

58:01I recently had the opportunity, I think you did too, to interview Dr. Ray Dorsey. I think you had him on your podcast. Yeah. And he made it very clear that he considers Parkinson's, for example, to be a man-made disease as a consequence of first the Industrial Revolution and our exposure even back in the 1800s when James Parkinson wrote his treatise on the shaking palsy is what his book was about. And he didn't describe what was, you know, it was a toxic event, but this was when people began to be exposed to these higher levels of toxins and even to this day. And, you know, by and large, the toxins that are at play here are toxins that threaten mitochondrial function.

58:46When we threaten mitochondria, we threaten the microglia and cause them to shift to becoming the evil twin. It's really that straightforward. We're threatening metabolism. And this is again, the term immunometabolism, the relationship between mitochondrial dysfunction and this dramatic life-threatening change of our microglial cells, our brain's immune cells. So what Dr. Dorsey made very clear is that we are exposed to a variety of toxins these days in our environment that directly target mitochondria and therefore can manifest as things like Parkinson's. As you discussed in your interview of Dr.

59:27Dorsey, he's really very much fixated on this trichloroethylene, which had been used in industrial cleaner, dry cleaning fluid, makes its way into water, you know, and there are places where groundwater is still contaminated by TCE. And, you know, in my lecturing, I've opened up this discussion a little bit further, looking at first something I alluded to earlier, this MPTP contaminant of this IV drug that people were using in the 80s and getting Parkinson's because MPTP targets the mitochondria. Well, are there any mitochondrial toxins that we may be exposed to these days? And the answer is you bet there are.

1:00:10Let's talk about something called paraquat. What is paraquat? Paraquat is an herbicide. It's used to kill weeds around our crops. The good news is that 70 countries around the globe, because it is such a devastating toxic experience, exposure to paraquat, have banned or significantly reduced the use of Paraquat in agriculture. The country that is not on that list is the United States. In the United States, our usage of Paraquat, a mitochondrial toxin, is skyrocketing. The reason being that our weeds are less responsive now to glyphosate. So they're developing what's called roundup resistance. So we've had to turn to the use of Paraquat, a mitochondrial toxin exposure to which is associated with increased risk of Parkinson's to treat the weeds in our modern agriculture.

1:01:11And let me be really clear about this paraquat thing. Paraquat is used experimentally to create Parkinson's in primates in research laboratories. And we are spraying it on our food. Something's wrong here. Something's very, very wrong. That we are, you know, it's been said that man is the only animal who will be fouled his own nest. So, you know, we're spraying a mitochondrial toxin on the food we eat. Something's wrong with that. Taking it even further, glyphosate itself, the active ingredient in Roundup. buy it at the hardware store and, you know, spray it around your vegetables. I'm telling you not to do that, uh, is similarly a mitochondrial toxin.

1:01:57And we're seeing the politic around, uh, glyphosate currently, and we'll see how that ends up, uh, playing. But, you know, we live in a toxic world. It's, it's true. And let me just pivot a little bit here to something I think that's really fairly germane, as you and I have this discussion in the summer months where wildfires are rampant in North America, recognize that, you know, these are by and large forests that are on fire, but it's not like this smoke is benign when it's coming to our cities and we are breathing this. These particles, these PM2.5s are powerfully pro-inflammatory, meaning they increase the cytokines in our bodies that make their way to the brain and will shift our brain defenders, microglial cells, to becoming brain destroyers.

1:02:48And also the PM2.5s themselves can be inhaled and make their way through the nose into the brain directly and can induce inflammation. Takes me to one other topic I want to cover real quickly, and then we can unpack whatever else you want. And that is what we call a feed-forward cycle. that inflammation experienced from any source, be it the permeability of the gut, be it the PM2.5 particles that we might inhale, inflammation from any source will shift the microglia to becoming their M1 destructive phenotype, we call it. That is a pro-inflammatory phenotype, meaning that once those microglia shift to being the evil twin, and let's be clear, they can shift back.

1:03:35That's what our work is all about. But once they're in that M1 damaging configuration, they are spitting out more and more of these damaging cytokines in the brain that further target other good microglial cells and shift them to being on the dark side, if you will, like zombies. So it becomes a feed forward process. So you can induce that shift from from head trauma, for example. That's why these football players with chronic traumatic encephalopathy continue to worsen once they've stopped, you know, after playing football. Look at Muhammad Ali, quit boxing, stopped the head trauma, but continues to worsen.

1:04:15Once this process has taken hold, it's a feed forward progressive event, but not impossible to stop. Can very well be stopped, as you've demonstrated in your patients in whom you've improve their cognitive function, as Dr. Bredesen has demonstrated, as I'm describing, as Dr. Tanzi described in his recent publication, you bet.

1:04:38Dr. Mark Hyman:And people are doing this. I mean, at our center, ultra wellness center in Lenox, Massachusetts, we do a lot of this. And we see these patients and we understand how to assess their nutritional status, insulin resistance, metabolic health, immune health, to look at mold, to look at toxins, to look at the microbiome. I mean, that's one of the big advances of functional medicine is really understanding how to optimize the microbiome to what we call the 5-H program as a reset for the gut. And these are just a different set of lenses and a different set of tools we use to address these kinds of chronic, often very, quite scary illnesses.

1:05:11Dr. Mark Hyman:But we can really make a difference. And I think, you know, your work has just been so inspiring for me. This book is incredible. I encourage everybody to get a copy of it, Brain Defenders. and the subtitle of this amazing book, Brain Defenders, is Harness the Power of Your Immune Cells to Protect Your Brain for Life, which is what you have to do. Before we close, David, I'd love to just do a rapid fire set of questions. You up for that? Are these double value, two points each? Yes. Go ahead. Okay, what's the single worst daily habit for your brain health? I would say lack of connection. Lack of connection to others, yes.

1:05:46Dr. Mark Hyman:I like that. And just as a side note, but there's my new book that I'm sort of working on. I talked about this guy, Steve Cole, who's come up with this whole science of how disconnection and loneliness actually activates a whole gene expression pattern that drives inflammation. So you're right on target. What's the single best daily habit for brain health? Connection to others. Okay, there we go. How about alcohol? Is it ever good for the brain? It's never good for the brain. You know, our messaging has changed over the years. It's a toxic event, and it's never good for the brain. How about sleep?

1:06:24Dr. Mark Hyman:How many hours should people sleep every night? Ideally, seven to eight, not just quantity, but I think it's important to study your sleep, wear the Apple Watch or the Oura Ring, and get a sense of the quality of your sleep. You kind of addressed this a little bit, but what's more important for the brain, aerobic exercise or strain training, if you had to pick one? If I had to pick one, I would probably say aerobic. And then walking. Is walking enough or do you need to do more? It really depends on the individual. What does walking do for you? Can you brisk walk and get your heart rate up to where it needs to be?

1:06:56That's the question. But I think walking on an incline is going to help build muscle mass, which is important as well.

1:07:02Dr. Mark Hyman:Yeah, if you're a marathon runner, walking probably won't do it. But if you're couch potato, it probably wouldn't have to start. How about blood tests? What's the most important blood test that people are not getting, but they should? Fasting insulin. Agreed. Agreed. Wow. We're on the same page, David. If Mark Hyman agrees with me, I'm doing well. What's another symptom that makes it bad in the long run for your cognitive health? Increasing waist size. Ah, so your belly fat. Belly fat. Yeah, that's a good one. Okay. Is it ever too late to improve your brain health? And can you really reverse loss?

1:07:36Dr. Mark Hyman:We've talked about it. Is it too late? Is there a point at which it's too late? Well, there's certainly a point in which it's too late. I think end-stage Alzheimer's is too late. But as we now see, interventional trials using lifestyle modification have proven effective even in individuals with established Alzheimer's disease. What's one food that you eat regularly for your brain? Salmon. Salmon. Okay, you're catching it up there in British Columbia right now. I caught one last night when the sun was coming down. Yeah, it was great. With an orca in the background. I love that. How about what spoon food you avoid?

1:08:12Dr. Mark Hyman:Fruit juice. Fruit juice. Yeah, no fruit juice. Orange juice is not a health food. And what is one supplement with the strongest evidence that you would take for your brain health? Vitamin D. How about GLP-1 drugs? Are they going to be brain health drugs? My sense is quite likely. I think there is some refinement that's obviously needed. We've seen an incredible interventional trial published in the New England Journal of Medicine where Parkinson's was stabilized. I think GLP-1s have a future in the brain health arena. Interesting. So it's an evolving story. We'll pay attention. Okay, what's more important for your brain?

1:08:47Dr. Mark Hyman:Doing brain games or staying socially connected and intellectually engaged? I would say socially connected for sure. And if you're a 40-year-old right now, what are three numbers you want to know that reflect what's happening in your brain? You need to know your fasting insulin level, your fasting blood sugar, and I would say your waist-to-hip ratio. Those are good. It's all metabolic health. Okay, now lastly, finish this sentence. The best way to stay mentally sharp for the next 20 years is? To change your thinking today to the extent that you realize that you are in control of your brain's destiny.

1:09:22Dr. Mark Hyman:You are in control of your brain's destiny. That is a big one. I think people all understand this about their heart or their weight, but they don't understand that their brain health is in their control. And I think that's what so much of York has been highlighting for the last 40 years. This last book, Brain Defenders, Harness the Power of Your Mute Cells to Protect Your Brain for Life, is amazing. It's out now. You can check out David's website, drpromutter.com. He's got a podcast, and you'll learn all about his amazing work. He's definitely one of my mentors and one of my close friends. I'm happy to be in this world with him because without him, I would be much less smart.

1:09:56Dr. Mark Hyman:So thank you, David. I love you, brother. I love you, too. I love all that you do. Good to see you. All right, buddy. Thanks so much. enjoy salmon fishing in British Columbia. If you love this podcast, please share it with someone else you think would also enjoy it. You can find me on all social media channels at Dr. Mark Hyman. Please reach out. I'd love to hear your comments and questions. Don't forget to rate, review, and subscribe to The Dr. Hyman Show wherever you get your podcasts. And don't forget to check out my YouTube channel at Dr. Mark Hyman for video versions of this podcast and more.

1:10:27Dr. Mark Hyman:Thank you so much again for tuning in. We'll see you next time on The Dr. Hyman Show. This podcast is separate from my clinical practice at the Ultra Wellness Center, my work at Cleveland Clinic, and Function Health, where I am Chief Medical Officer. This podcast represents my opinions and my guests' opinions. Neither myself nor the podcast endorses the views or statements of my guests. This podcast is for educational purposes only and is not a substitute for professional care by a doctor or other qualified medical professional. This podcast is provided with the understanding that it does not constitute medical or other professional advice or services.

1:10:57Dr. Mark Hyman:If you're looking for help in your journey, please seek out a qualified medical practitioner. And if you're looking for a functional medicine practitioner, visit my clinic, the Ultra Wellness Center at ultrawellnesscenter.com and request to become a patient. It's important to have someone in your corner who is a trained, licensed healthcare practitioner and can help you make changes, especially when it comes to your health. This podcast is free as part of my mission to bring practical ways of improving health to the public. So I'd like to express gratitude to sponsors that made today's podcast possible.

1:11:27Dr. Mark Hyman:Thanks so much again for listening.