Don't Wait for Alzheimer's — A Neurologist's 30-Year Plan to Protect Your Brain with Dr. David Perlmutter

Mark Hyman, MD

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

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

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Full Transcript

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

Dr. David Perlmutter
When we recognize that forty to fifty percent of adults in America who live to be age 85 will have a diagnosis of Alzheimer's disease, at 65 years and older, risk is one in nine or eleven percent of people aged 65 or older have dementia. It is almost a fully preventable situation that people shouldn't fear, that people should feel empowerment as it relates to making the right choices.

Dr. Mark Hyman
David, welcome back to the podcast. So good to see you again. And I know you're coming in from British Columbia, which is exciting. And I I think, you're you're taking well deserved rest before the launch of your new book, Brain Defenders, which I'm very excited about. How to harness the power of your immune cells to protect your brain for life.

We're gonna get all into that and go deep on this because it's really an important topic. You know, David, I I I think, you know, we've known each other for, I don't know, cut thirty years now, and and you were one of my mentors. You originally taught me so much about the brain that I recollecting about the original book that you had had written that helped me understand Parkinson's, mitochondria. And you you were the first one to talk about this idea of the brain on fire.

Dr. David Perlmutter
That's

Dr. Mark Hyman
right. And you you had this really crappy slide.

Dr. David Perlmutter
What? All of our slides were crappy back in

Dr. Mark Hyman
the day. And it was at the conferences, and it it really stuck with me. And it that so much of what's wrong in the brain, whether it's neurodegenerative diseases or mood disorders, The whole spectrum of brain dysfunction is in some ways tied to dysregulation of immune function and immunity and inflammation of the brain. And your new book goes really deep on this. So maybe you can kind of start out by helping us understand a few things.

Why are you focusing now on this whole framework of immunometabolism, the mitochondria, and the immune system interacting in the brain as a root cause with so much of what we're seeing that's wrong in today's brains?

Dr. David Perlmutter
Well, Mark, this represents, I I think for me, a a significant convergence of everything that we've been talking about for such a long time. And I've it it's incredible because it really unifies, the mechanisms that we've talked about. You you mentioned the brain on fire. This embraces the idea that neuroinflammation is a central player in what makes a good brain go bad. But beyond that, well, then where does the inflammation come from?

And it comes from exactly what you described, those microglial cells, these brain immune cells, the innate brain immune cells. Who knew that the brain had its own immune system? And, you know, we tend to think about, well, that's what makes a good brain go bad. And the reality is these cells are, I hate to say designed, but what they're what they do on a good day is maintenance and good things. They maintain our synapses.

They maintain the function of the neurons. They maintain the blood brain barrier. So it really broadens the scope of what we would classically consider to be immune function. When you ask somebody, what does the immune system do? And the response is going be, well, that's what comes into play when there's a challenge, by a bacterial infection, viral infection, surveillance for cancer cells, whatever it may be.

But the reality is that, you know, these firemen in the firehouse are doing a lot of work, to maintain the fire engine when there's no fire. And I think that's that tends to broaden our understanding of this immune system. It has a good side and a downside. And to be very technical about it for our discussion today, these microglial cells can exist either in a very supportive, we call it the m two role, where they're shoring up these barriers and keeping our synapses working, or they can shift to being destructive, what I call in in the book, the evil twin, the m one configuration, where they are going around and destroying the synapses, creating that neuroinflammatory environment where the neurons can't work well anymore, and the blood brain barrier becomes more permeable, letting bad things into the brain. And that said, the most empowering part of our discussion today is that the shift from being supportive to being destructive is under our control.

And, you know, for me, that really represents a whole heck of a lot because it explains everything we've been talking about for so long. It explains why, you know, in GrainBrain, why a higher carb diet, and we'll unpack this today, is associated with activation of these microglial cells. It explains why permeability of the gut for all you know, of all things, from having changes in our gut, bacteria leads to increased inflammation that will activate these microglial cells and shift them to becoming, again, the evil twin. We now see that we can, research wise anyway, image the brain in living humans using what's called a TSPO scan. This scan images when the microglia are activated to their destructive state.

So a positive TSPO scan shows activation of the microglial cells. And we see that the TSBO scan is positive, as you would expect, in Alzheimer's, in Parkinson's, in multiple multisystem atrophy, progressive supranuclear palsy, major depressive disorder, post traumatic stress, and even long COVID. So really, it this whole notion of activation of the brain's immune cells called microglia throws an incredibly large net, and that is giving us all a level of empowerment now that we've never had access to in the past.

Dr. Mark Hyman
You know, I think I think there's a whole new way of thinking about the brain. I think we've we've kind of lost this sort of central idea in medicine, which is that we can help the brain. We know we can prevent heart disease by lifestyle. We know we can prevent diabetes by lifestyle. I mean, we even know in some ways cancer can be prevented by reducing toxin exposure and helping with your metabolism and a lot of other things.

But brain health is just something that we we think of as this black box and that traditional medicine doesn't know what to do with. It's like, okay. Well, I'm I hear so much of this from my friends who have family members with Alzheimer's, and they go, well, I don't wanna know my test because there's nothing I could do. They're in this fatalistic view that the brain is fixed or it's it progresses towards disease with with this inextricable path that can't be altered. And in this what's so important about your work and and the things that you highlighted, you know, decades ago and that you continue to work on is that the brain is is changeable, that the brain can be influenced by what we're doing, by our microbiome, by our diet, by exercise, by sleep, by our nutritional status, by reducing exposure to environmental toxins, by helping our mitochondria work better.

There's so many pathways to actually improving brain function and not only just slowing and preventing neurodegenerative diseases like Alzheimer's or Parkinson's, but actually intervening and reversing many of them. And that's kind of a heretical thing to say in medicine. Some of what

Dr. David Perlmutter
you just said. You're right. It's considered heretical. But as our colleague Dale Bredesen has mentioned many times, we all know of cancer survivors. Do we know of any Alzheimer's survivors?

And now we're starting to see that happen. And it's really based upon what you just described, and that is these metabolic inroads. And that is what you originally teed up for our conversation today, this concept of immunometabolism. Immuno being what we're talking about, these microglial cells in the brain, the brain's immune cells, and their metabolism. So when these immune cells shift their metabolism, when their metabolism changes, then they shift in becoming the evil twin.

They shift from being supportive to being destructive. It's all predicated on their metabolism that changes. Their mitochondrial function is declining suddenly and rapidly, and that induces this shift to becoming what we call M1 and destructive. And here's the take home bullet point message, and that is that the metabolism of the microglial cell mirrors the metabolism of your body. Wow.

That is incredibly empowering. So if I dedicate my lifestyle choices to improving my body's metabolism, to keeping my weight down, to keeping my blood sugar in check, to keeping insulin functionality where it needs to be, to keeping keeping my blood pressure where it should be, then I am actually working lovingly with my microglial cells to really become the architect of my brain's destiny. And, you know, in in my case, having a family history of, Alzheimer's, it's what I need to do, and I am certainly not alone in that. When we recognize that forty to fifty percent of adults in America who live to be age 85 will have a diagnosis of Alzheimer's disease tells me a couple of things. Number one, that's a flip of a coin, and I wanna make sure it it lands on the right side for me and for everyone I'm interacting with.

Yeah. Number two, we should absolutely consider this to be an epidemic. That segment of our population is the most rapidly expanding. And when you look at those statistics in terms of Alzheimer's risk, I mean, 65 years and older, risk is one in nine or eleven percent of people aged 65 or older have dementia. I will say here on your podcast, it is almost a fully preventable situation that people shouldn't fear, that people should feel empowerment as it relates to making the right choices.

It's an awful situation for certainly the patient and for the loved ones as well. Having been through that, you know, I again, I want to dedicate everything I do to giving people this information that this just we can rewrite your brain's destiny.

Dr. Mark Hyman
I think that's important, David, and this is such an important concept that we we can do stuff to keep our brains healthy, functioning, and mentally sharp. And the question is, you know, I'm 66. You're a little bit older than me, not too much. And you're like, a little ahead of me like my Tell

Dr. David Perlmutter
you what. I'm on the continuum.

Dr. Mark Hyman
You're you're my big brother. You know? Like, how how do we keep our brains healthy for the next twenty years? So we're thinking about it for ourselves, but it's it's it's a really an important concept. What causes brain damage?

What can I do differently now to make sure I stay mentally healthy and my brain stays healthy and I have no neurodegenerative diseases over the next twenty years? And what should I be measuring and looking at in my own biology to track what's happening? And and and this is important for us to sort of unpack, I think, because, you know, we we know that the changes happen in the brain decades before you ever forget your keys or somebody's name or, you know, get lost in a grocery store. The these are things that happen, you know, in their thirties, forties, fifties before you see any changes in people's sixties, seventies, and eighties. Can can you help us understand what are those things we should really be thinking about in terms of what is causing brain damage, and how do we stop that?

How do we how do we stop this fire in the brain that you've been

Dr. David Perlmutter
Yeah.

Dr. Mark Hyman
So elegantly describing for decades, and this this kind of how do we optimize our metabolism, reduce inflammation, and all these core concepts? Because it we know now so much more than we did even when we all started this thirty years ago that that it's it's really doable. Well, I I think the most important step is that you embrace the idea that you are in charge.

Dr. David Perlmutter
If you don't do that, then, you know, you're not going to pursue the other things that we will now talk about. So, really, job one is I am the architect of my brain's destiny. Okay. Doctor. Perlmutter, doctor Hyman, what do I do?

That's your question. And and the reality is, it's not difficult. It's not really that sophisticated. If what makes a good brain go bad across the entire spectrum of neurodegenerative conditions yes, we're fearful of Alzheimer's, but there's a long list of other of other things that can make a good brain go bad. That's for sure.

I mean, you know, people don't realize that Parkinson's is also influenced by metabolism. If you have type two diabetes, your risk of Parkinson's is increased by eighty five percent. So this notion that metabolism is important is, you know, the answer to your question, we've got to do everything we can to remain metabolically intact in our forties and fifties. We have a big buffer there cognitively, such that we don't really see the cognitive changes in the brain until, you know, maybe we're in our sixties, maybe we are in our seventies and are forgetful of our keys, Wi Fi codes, grandchildren's names, etcetera. We're way down the continuum of brain decline when that stuff starts to happen.

And you're exactly on point that the issues that sow the seeds for the brain's degeneration happen when we are a lot younger, in our thirties and in our forties. That's who I'm hoping are listening to our conversation today because that's when we really begin to establish our personal set points as it relates to metabolism. That said, to answer one other part of your question, then what are those markers? And they are very straightforward, simple markers that you've talked about for years. How important is your fasting blood sugar for your brain's destiny?

It is fundamental. Know your fasting blood sugar. And and that is something as need I tell you, you don't need a doctor's prescription to understand your fasting insulin level, your A1C. Want to take it a little deeper? Let's look perhaps at your C reactive protein.

And as I describe in the book, there are a suite of very brain specific blood tests that we can get, like p tau two seventeen, which we we could talk about. But the main players are, those blood tests that I mentioned that look at your blood, metabolic markers, know your blood pressure, and and buy a very, very sophisticated and expensive tool called a tape measure, and put it around your belly and put it around your waist. And then do the math and determine your waist to hip ratio. And, you know, this is an extremely valuable way of understanding what is your risk. How does that relate?

Well, when your belly is big, you have more visceral fat and you're increasing inflammation. Those microglial cells in your brain that are in charge of whether your brain will be healthy or not, call it like it is, are very receptive to inflammation coming from anywhere in the body. When inflammation chemicals called cytokines are produced anywhere in the body, like from a leaky gut for all, who who knew. Right? Those chemicals can make their way to the brain through the blood brain barrier that becomes less and less functional as we age.

Those microglia see inflammation, and they shift to becoming the evil twin. Now that they're shifted to becoming the evil twin, they go around the brain and destroy synapses. The the the main issue in the Alzheimer's brain that leads to decline in cognitive function is the loss of connection, one neuron to the next, via the synapse. That's the connection. So at a microscopic level, it's a loss of connection.

At a macroscopic level, Alzheimer's patients lose connections with themselves, with people around them, and with their entire environment. So this loss of connection is really, you know, kind of the central issue that is involved in the Alzheimer's brain. But, you know, we lose connection in Parkinson's as well. We lose connection of these cells that make dopamine in the part of the brain called the substantia nigra projecting to other motor areas. And it's the same mechanism that was demonstrated by Doctor.

Langston in the 1980s when he, first saw these patients who used a designer IV drug that was contaminated, the microglia were activated in their brains immediately and destroyed those cells that made the dopamine. And immediately, they got Parkinson's. And he studied their brains thirteen, fourteen years later, and these microglia were still at it, still destroying tissue. So this is you know, Science Technology magazine called this the number one discovery of twenty twenty five, the incredibly central centralized role of microglia in brain degeneration. And, gratefully, it's great to have another explanation finally that takes us away from this idea that, for example, Alzheimer's is caused by ask anybody.

They'll tell you what causes Alzheimer's, the accumulation of beta amyloid in the brain. I think my blood pressure just went up saying that because I'm really getting tired of hearing it and reading. I read it last night, in some news report that what can we do to lower beta amyloid. That is absolutely not the cause of Alzheimer's disease. I I say that in the book, provide the data, explain how the whole amyloid hypothesis was flawed.

But when we look at that discussion through the lens of these new amyloid targeting drugs, they are not working. If beta amyloid is the cause of Alzheimer's, then you would think getting rid of the beta amyloid might do some good. A Cochrane analysis was published about two months ago. This was an analysis of the 17 top studies that evaluated the effectiveness of the drugs that do indeed lower beta amyloid in the brain. The study that involved 20,342 individuals, each study lasting about eighteen months, looked at two things, risk and benefit.

That's what we always do, right, to determine, are we gonna write a prescription for something, an intervention? What's the risk and what's the benefit? What they found was the benefit was zilch. That's not the word they used. The word they used was trivial.

They don't work, and the risk was really high. Twenty to twenty five percent of these people on these drugs develop brain hemorrhages, brains and or brain, swelling or or even death and for a drug that doesn't work. So that's a powerful argument against putting people on these $40,000 a year intravenous infusions every two weeks. And the response when I when I challenge doctors who are doing this therapy is, well, we've got to do something.

Dr. Mark Hyman
There's nothing else to do. Right? But that is

Dr. David Perlmutter
You've got to do something.

Dr. Mark Hyman
You've got

Dr. David Perlmutter
to offer something. Well, you're offering something that is very threatening and has no efficacy. So that that raises the hair on the back of my neck. And so what do you do in a situation like that? You write a book.

Dr. Mark Hyman
Thank god. I mean, one of the things I think, you know, you you hinted it a little bit, which I think is important to double back on, is is this really important idea that all the conditions that happen to the brain, Alzheimer's, Parkinson's, ALS, MS, long COVID, fibromyalgia, chronic fatigue, mood disorders, psychiatric disorders, they're all related. They may manifest differently in different people based on their particular unique genetics or predispositions, but the fundamental mechanisms underneath all these things are very similar. And they have to do with our our inputs. Right?

The things that we have control over, our diet, our lifestyle, exercise, stress, sleep, all that, environmental toxins, and our microbiome. And and then the downstream effect is very similar dysfunctions around inflammation, around mitochondrial dysfunction, metabolic dysfunction, you know, oxidative stress. These are all things that we actually have been talking about for decades in functional medicine, and we're down you know, into the kind of weeds of things looking at these diseases rather than kind of zooming out and saying, okay. What do they have in common? What can we do to optimize our overall health, but particularly our brain health, you know, from this lens?

And and that's what we should be focusing on. And and I think, you know, the you know, this is a very powerful modality. I remember I had a patient who had pretty significant dementia. We really helped her in so many ways. She had heavy metals.

She had methylation issues. She had gut issues. We we fixed a lot of things, and she kinda did really well for quite a while. Then she had a decline because her husband died, and it was a big loss for her.

Dr. David Perlmutter
And

Dr. Mark Hyman
I said, well, why don't we just try a ketogenic diet? And this might have been twenty years ago because, you know, I was reading about the literature and mitochondria and inflammation and insulin resistance to the brain and type three diabetes, which would be Alzheimer's. I was like, let's try it. And it was it was amazing. You know?

The the family was wealthy enough to have a chef. They gave her the food, and it was like she woke up. And, you know, it it lasted for quite a while, and it just it just alerted me to the fact that even in people who are are fairly down the road, there there are things that can be done to really help this. And as you mentioned, you know, Dale Bredesen is talking about the Alzheimer's survivors. You know?

Nobody's who's an Alzheimer's survivor? Nobody. Right? But there are now people, and I've I've had them in my practice as you have, that and when you aggressively treat these factors, the causes, and you optimize the immune system, you optimize mitochondria, metabolic function, that these people do better. And it's quite remarkable.

Yeah. You bring up a really

Dr. David Perlmutter
good point. I don't wanna miss this while it's still, in our minds, and that is

Dr. Mark Hyman
Yeah.

Dr. David Perlmutter
That you mentioned mitochondria multiple times, and that is the metabolism of these microglial cells. And, ultimately, when the microglial cell shifts from being supportive to being disruptive, it actually is characterized by a loss of mitochondrial function. The m one disruptive microglial cell does not use mitochondria to any significant degree. It's using glycolysis, so its energy production is much less efficient, much less ATP produced. So in a very real sense, all of those neurodegenerative conditions that you listed are mitochondropathies or based upon failure of their mitochondria.

You can get there from mold exposure, from having insulin resistance, from head trauma, from exposure to environmental toxins, from PM two point fives 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.

Dr. Mark Hyman
Well, there was something really new that you said in your 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 of the immune cells. And that was a kind of an for me. Like, wait a minute. The metabolism, mitochondria, of immune cells, when it goes awry, is what's causing so much of the brain inflammation and the brain and fire that you've talked about for so long, and it's contributing to all these neurodegenerative and neuropsychiatric disorders.

Is that right?

Dr. David Perlmutter
Immunometabolism. What a term.

Dr. Mark Hyman
So talk about this because I think this is a new a new idea. I mean, Jeff Blandis 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? How do we start to think about it? How do we start to act on it and even diagnose it?

Dr. David Perlmutter
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. It 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, 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, you know, the markers of metabolism that we can easily measure. When 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 two seventeen, which is a blood test you can get, you know, doing function health, for example, you can go and get your p tau two seventeen measured, is a very valuable indicator of loss of synapses. If you really want to know what it's telling you, the higher the level of this p tau two seventeen a 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 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 you're evaluating what next is 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 your waist to hip ratio.

Dr. Mark Hyman
Yeah. I think it's important. Let's just kinda double down on this because I think this is a really this is a 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, if you diabetes oh, my blood sugar is high about diabetes, my blood pressure is high about high blood pressure. 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 we could check your APOE four gene, which gives you a risk of Alzheimer's, but those are genes that can't be changed. You can change your expression of them. But now we have biomarkers that are really revolutionary, I think. It's it's it's like a it 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.

You know? 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. You know? Maybe my p tau two seventeen 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. 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 it gives you an opportunity to think about creating a plan for yourself that that's very proactive instead of reactive. I mean, by the time you are an end stage Alzheimer's, there's not a whole lot you can do. But early on, you can see a lot of things changing. And then this 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, all a lot of things you're mentioning. And so resistance markers, insulin a one c, particle size, hormone levels, toxin levels, nutritional levels, homocysteine, all the things you'd wanna look at as a foundation. But we also offer an advanced sort of brain panel, allows us to look at p tau two seventeen, amyloid a d forty two forty, looking at neurofilament light chain, which is often, you know, damaged when the brain's damaged from traumatic brain injury and other injuries, and and GFAP, which is another protein. So there's a lot of things you can look at. And so I think for me, it's it's a really empowering moment in in in neurology.

And and, yeah, I mean, I'm gonna make fun of you. You're a neurologist, but the the joke we had about neurologists in medical school was diagnosed in adios. Basically, you would just you would be great at diagnosing things, but there was nothing you could do about it.

Dr. David Perlmutter
It is so

Dr. Mark Hyman
true. And and, you know, now that like diagnosed in adios is diagnosed in in Ola, almost us. Let's go.

Dr. David Perlmutter
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. And what you're describing is the approach of keeping people healthy in the first place. Which is more valuable? I mean, would submit it's absolutely the latter.

And, you know, we describe our health care 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 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, Sunny Boy. But 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 them or whatever the interval was, have a mammogram. Mammograms don't prevent breast cancer. Excuse me. They early detect breast cancer.

So I I think that what you're describing, and in fact, that suite of blood tests that you described, you know, the g a glial fibrillary, the GFAP, the neurofilament light, NFL, the looking at phosphorylated tau, p tau two seventeen. 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. And and, you know, people talk about, well, what about your genetics? And what if I do carry the APOE four allele, and I know, therefore, if I'm heterozygous, I have a fivefold increased risk. If I have two of them homozygous, my risk for Alzheimer's may increase twelvefold.

Should people even know that? And my answer is, you bet a 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 health in order, and you can, absolutely rewrite your destiny. And that's what this is all about. And and it does it fly in the face of modern medicine, how medicine is practiced here in America? Yes, indeed, it does.

I mean, you know, we see how the deck is stacked, and that's okay. I mean, Robert Kennedy senior 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? Hundred percent. If that existed, if GLP ones turn out to be effective, I'm gonna sign up for that.

You bet. I will I will be recommending that, and I talk about that in the book. I you know, 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, you know, having mentioned GLP ones, I think there is some promise there. But for now, let's do the metabolic work.

Dr. Mark Hyman
Yeah. I think it's so important. And and your the name of your book is so important, Brain Defenders, because it it talks about how to how do we defend our brain. Like, what are the things we can do to defend our brain? And right now, I think people don't really know.

Like, they know if I I shouldn't smoke and I should manage my blood pressure and I should, you know, 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 on going

Dr. David Perlmutter
just said. Go ahead.

Dr. Mark Hyman
Well, it's those things too. Yes. It's like, the good news is what treats anything treats everything. You know? It's kind of like a 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 that determine who we are. And and those things are highly modifiable, and we can't change our genes or we can change the expression of those genes. And so let's talk about, like, the fundamental things that that people can do other than the looking at these these causes, right, and looking at the blood tests, which help 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 I I mean, the brain and the body are the same. Like, it's not like we have you talk about the body mind, mind body. This is one thing. It's not like two things. So I think that we kinda get all confused about that.

But I I think we really need to think about, you know, what are those things that people can can do very practically that had the most impact on the brain? And maybe you can walk us through what you what you discovered around how to optimize immunometabolism related to the brain.

Dr. David Perlmutter
You bet. And and again, you know, there so many things, came to mind when you in that setup. And and first, you know, 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 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. Alright. Now where are those what are the decisions? And I'm not gonna 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 by the 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 fifty percent reduced risk for developing dementia. And by and large, these modifiable factors are the things we've already talked about that affect metabolism. Interestingly, as a kind of a sidelight, they did not mention diet. They did not mention nutrition. So I, along with doctor Robert Lustig, wrote a letter to the Atlanta editor saying, hey.

You know, it must have been an oversight. Here are the references that 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 gonna publish your letter to the editor. So I don't know what's going on with that. We'll leave that.

But let's let's first talk about exercise. So, you know, the data that that relates regular exercise with reduced risk of cognitive decline is vast. And, you know, that really came to us in actually the late 1980s from a doctor 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. And 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.

You know, the 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 period of time demonstrating that when they change 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. By and large, it stopped declining completely.

Dr. Mark Hyman
That's crazy.

Dr. David Perlmutter
And in fact, this is in seventy percent of their interventional people. In many of them, it actually improved. I'm gonna 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 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 weight lifting 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, a 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, therefore it's an endocrine gland, more involved in, you know, regulating metabolism. The aerobic part of the story improves blood supply, improves insulin functionality. So it's it's the combination. 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 age 65 or older, you and me, and also those individuals who 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.

Dr. Mark Hyman
Great. Well, I I worked out in the gym this morning at seven, and I went for a hike up the mountain. So, like, I got my I got my exercise in. My brain feels good. So, David, let let's talk about a a few other things around diet and and what is so crucial to understand for people as they bring a healthy diet.

And I think I think we've talked about this a lot, but I think it'll be good to just crystallize your thinking about this in 2026.

Dr. David Perlmutter
What I endeavor to do in Brain Defenders is simplify because as you all know, there there are so many diets out there, whether it's Mediterranean, Mediterranean Plus, added greens, the MIND diet, you know, 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 but with some stipulations. And I think most importantly, it's a diet that's going to control your blood sugar. And I I will say that we've got to get some metrics here, and 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 I'd 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 described 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.

So I 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 doesn't the outcome doesn't get, as much attention as it needs. And that's what I focused on in this book.

Dr. Mark Hyman
Yeah. And and also, think, you know, 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 related to changes in the microbiome and gut dysfunction. And and maybe you could kind of talk about that because you wrote a whole book about that, but I think 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 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.

So can you kinda talk about a little bit about the microbiome and the brain in that context?

Dr. David Perlmutter
You bet. And 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 and the gut is somewhere South of Los Angeles. And so, yeah, it was an interesting time, but now I think the the mechanisms have been, you know, much more fully fleshed out, delineated that we can understand, you know, the the fundamental relationship between what's going on in the gut, even beyond the microbiome, but 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.

You that's the term you use. Make 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.

Dr. Mark Hyman
I probably did at some point.

Dr. David Perlmutter
I 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, and 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? People may have heard of that, lipopolysaccharide. 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 a publication publications 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 setting 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. Now 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% of calories are coming from these frankenfoods, as 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? Be still my beating heart. And this study that came out last year followed a group of 1,111 individuals over a period of twelve point seven years and basically asked these folks during this twelve point seven year during the period of time that we're gonna 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 thirteen percent increased risk of Alzheimer's disease, a disease

Dr. Mark Hyman
Just one serving. Woah. That's not much. That's a

Dr. David Perlmutter
handful of chips. That's a thirteen percent increased risk of Alzheimer's, a 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 in the context of a country where 60% of our calories is coming from

Dr. Mark Hyman
those foods.

Dr. David Perlmutter
So that's not out of that's 10 No. Hand servings of chips.

Dr. Mark Hyman
That's probably on the low end.

Dr. David Perlmutter
Yeah. Their risk has increased two hundred and seventy percent. That's of a disease for which we have no meaningful pharmaceutical treatment.

Dr. Mark Hyman
So Two hundred and seventy percent.

Dr. David Perlmutter
Two yeah. Three basically, a threefold increased risk of getting Alzheimer's, which, you know, you if you live to be aged 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 vis a vis the discussion we just had. We know that's bad. When 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. These 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.

Dr. Mark Hyman
I I think you're you're what you're saying is so important. 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 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 are everywhere. We're exposed to so many of them, and yet many of us don't really have a a way of sort of understanding how to diagnose them or treat them. And and we feel a little bit confused because it's like, well, what do we do? And I think I think you and I both been involved in this field, and and I think that having a 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. I I think that was one of the biggest 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 all phenomena of autogens, are autoimmune inducing toxins. The same can be true for the brain, I think. So maybe you can sort of help us understand that a little bit.

Dr. David Perlmutter
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 the 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 let's look at toxins that are directly affecting, the mitochondria. I recently had the opportunity, I think you did too, to interview doctor Ray Dorsey. I think you had him on your podcast.

Dr. Mark Hyman
Yeah. Yeah.

Dr. David Perlmutter
Yeah. And he 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 eighteen hundreds 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. When 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 doctor 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 Doctor. Dorsey, 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 and there are places where groundwater is still contaminated by TCE. And, you know, in my in my lecturing, I've opened up this discussion a little bit further, looking at first something I I alluded to earlier, this MPTP contaminant of this IV drug that people were using in the eighties 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.

Let'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, in that 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.

And let me be really clear about this paraquat thing. Paraquat is used experimentally to create Parkinson's in primates in research lab and we are spraying it on our food. Something, 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 befoul 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 at the hardware store, and, you know, spray it around your vegetables, I'm telling you not to do that, is similarly a mitochondrial toxin. And

Dr. Mark Hyman
Mhmm.

Dr. David Perlmutter
We're seeing the politic around glyphosate currently, and we'll see how that ends up 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 are having 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 it's not like this smoke is benign when it's coming to our cities and we are breathing this.

These particles, these PM two point fives, 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. And also, the PM two point fives 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 wanna cover real quickly, and then we can unpack whatever else you want. And that is a what we call a feed forward cycle. That inflammation experienced from any source, be it the permeability of the gut, be it the p m 2.5 particles that we might inhale, inflammation from any source will shift the microglia to becoming their m one 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 back. That's what our work is all about. But once they're in that m one 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 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. Once this process, has taken hold, it's a feed forward

Dr. Mark Hyman
Hard to stop. It's hard to stop.

Dr. David Perlmutter
But not but not impossible to stop. Can very well be stopped as you've demonstrated in your patients in whom you've improved their cognitive function, as doctor Bredesen has demonstrated, as I'm describing, as doctor Tanzi and described in his recent publication, you bet.

Dr. 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 is really understanding how to optimize the microbiome to what we call the five r program as a reset for the gut. And and these are just a a different set of lenses and a different set of tools we use to address these kinds of chronic, often very quite scary illnesses.

But but we can really make a difference. And I think, you know, your work has just been so inspiring for me. Your this book is incredible. I encourage everybody to get a copy of it, Brain Defenders. And 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. Are you up for that?

Dr. David Perlmutter
Are these double value, two points each? Yes. Go

Dr. Mark Hyman
ahead. Okay. What's the single worst daily habit for your brain health?

Dr. David Perlmutter
I would say lack of connection. Right? Lack of connection to others. Yes.

Dr. Mark Hyman
I like that. And just as a side note, there's a in 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 it's you're right on target. What's the single best daily habit for brain health?

Dr. David Perlmutter
Connection

Dr. Mark Hyman
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,

Dr. David Perlmutter
our messaging has changed over the years. Never it's a it's a toxic, event, and it's never good for the brain.

Dr. Mark Hyman
How about sleep? How many how many hours should people sleep every night?

Dr. David Perlmutter
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 as to the quality of your sleep.

Dr. Mark Hyman
You kind of addressed this a little bit, but what's more important for the brain aerobic exercise or strength 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?

Dr. David Perlmutter
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? That's the question. But I think walking on an incline is, you know, gonna help build muscle mass, which is important as well.

Dr. Mark Hyman
Yeah. If you're a marathon runner, walking probably won't do it. But if you're a 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?

Dr. David Perlmutter
Fasting insulin.

Dr. Mark Hyman
Agreed. Agreed. Wow. We're on the same page, David.

Dr. David Perlmutter
If Mark Hyman agrees with me, I'm doing well.

Dr. Mark Hyman
What's another symptom that makes it bad in the long run for your cognitive health?

Dr. David Perlmutter
Increasing waist size. Ah, so your belly fat.

Dr. Mark Hyman
Belly fat. That's a good one. Weighs okay. Is it ever too late to improve your brain health, and is you know, can you really reverse loss? We talked about it.

What is it too late? Is there a point at which it's too late?

Dr. David Perlmutter
Well, I 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.

Dr. Mark Hyman
What's one food that you eat regularly for your brain? Salmon. Salmon. Okay. You're catching it up there in the last in British Columbia right now.

Dr. David Perlmutter
I caught one last night when the sun was coming on. Yeah. It was great With a with an orca in the background.

Dr. Mark Hyman
Oh, love that. How about what's food you avoid? 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 one drugs?

Are they gonna be brain health drugs?

Dr. David Perlmutter
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 ones have a future in brain health, the brain health arena.

Dr. Mark Hyman
Interesting. So it's an evolving story. We'll pay attention. Okay. What's more important for your brain, doing brain games or staying socially connected and intellectually engaged?

Dr. David Perlmutter
I would say socially connected for sure.

Dr. Mark Hyman
And if you're a 40 year old right now, what are three numbers you wanna know that reflect what's happening in your brain?

Dr. David Perlmutter
You need to know your fasting insulin level, your flat your fasting blood sugar, and I would say your waist to hip ratio.

Dr. Mark Hyman
Those are good. It's all metabolic health. Okay. Now lastly, finish this sentence. The best way to stay mentally sharp for the next twenty years is?

Dr. David Perlmutter
To change your thinking today to the extent that you realize that you are in in control of your brain's destiny?

Dr. Mark Hyman
You are in control of your brain's destiny. That is a 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 forty years. This last book, Harness the Power of Your Immune Cells to Protect Your Brain for Life is amazing.

It's out now. You can check out David's website, drpromoter.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.

So, thank you, David for all these brother. I love you too.

Dr. David Perlmutter
Love all what you do. Good to see you.

Dr. Mark Hyman
Alright, buddy. Thanks so much. Enjoy salmon fishing in British Columbia.

Dr. Mark Hyman
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 Doctor Mark Hyman. Please reach out. I'd love to hear your comments and questions. Don't forget to rate, review, and subscribe To the Doctor Hyman Show wherever you get your podcasts.

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