Feel Better, Live More with Dr Rangan Chatterjee - How To Reduce Your Risk of Alzheimer’s and Keep Your Brain Young with Dr Tommy Wood #316

Episode Date: November 30, 2022

In the UK, one in 14 people over 65 will develop dementia, with that figure rising to one in six once we’re over 80. It’s fair to say it’s the disease many people fear the most. But this podcast makes it clear that cognitive decline is not a natural or inevitable part of ageing. During the course of this conversation, returning guest Dr Tommy Wood outlines plenty of simple, enjoyable things that we can all start doing right now to improve our brain health and stave off age-related dementia.   Dr Tommy Wood is Assistant Professor of Pediatrics and Neuroscience at the University of Washington, US. He holds a degree in biochemistry from Cambridge, a medical degree from Oxford, achieved his PhD in physiology and neuroscience in Oslo, and has published papers and lectured across the globe. It’s fair to say that when it comes to brain health and longevity, he knows his stuff.   We kick off our conversation with the empowering news that we can resist declining brain function simply by challenging ourselves more. We can make new cells, new connections and change the structure around them, harnessing the neuroplasticity of the brain. And it doesn’t matter if we’re 28 or 80, he says. MRI scans prove the brain can adapt at any age.   Tommy explains the importance of rest, for the brain to consolidate all its new pathways, and nutrition to provide the fuel it needs to function well and grow. We talk about the role of B vitamins and omega-3 fatty acids for brain development, and the fact there’s no one-size-fits-all when it comes to optimum diet.   We also talk about the similarity between training your muscles and training your brain. And the research conclusively shows that the more muscle mass you have, and the more you move it, the lower your risk of cognitive decline. Tommy talks us through the types of exercises and the number of reps we need to do to gain muscle and brain benefits. And it's probably less than you think.   We also cover the surprising value of video games, the importance of social connection, and why going to dance classes might just be the best thing you can do for your brain and body. This is a fantastic episode, jam packed with life-changing practical information. I hope you enjoy listening. Support the podcast and enjoy Ad-Free episodes. Try FREE for 7 days on Apple Podcasts https://apple.co/feelbetterlivemore. For other podcast platforms go to https://fblm.supercast.com. Order Dr Chatterjee's latest book Happy Mind, Happy Life: UK version: https://amzn.to/304opgJ, US & Canada version: https://amzn.to/3DRxjgp Show notes https://drchatterjee.com/316 DISCLAIMER: The content in the podcast and on this webpage is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or qualified healthcare provider. Never disregard professional medical advice or delay in seeking it because of something you have heard on the podcast or on my website.

Function will decline over time in anybody from your 20s or 30s it on average steadily decreases but you can change the trajectory quite dramatically the cells you have can make new connections you can change the structure around those cells in the brain which is what helps support their function and you can slow the rate of brain atrophy and cognitive decline hey guys how you doing Hope you're having a good week so far. My name is Dr. Rangan Chatterjee, and this is my podcast, Feel Better, Live More. Do you think that your brain function has to decline as you get older? Well, if you do, I think today's episode may pleasantly surprise you.

Maintaining the function of our brains is arguably one of the most important things that we can do. And what a lot of us don't realize is that there are some simple, enjoyable things that we can all start doing right now that will immediately start to improve our brain health. And my guest today, in my opinion, is one of the very best people to talk to us about this very topic. Dr. Tommy Wood is Assistant Professor of Pediatrics and Neuroscience at the University of Washington. He holds a degree in biochemistry from Cambridge, a medical degree from Oxford, and achieved his PhD in physiology and neuroscience in Oslo. Tommy has published papers and lectured across the globe, and it's fair to say when it comes to brain health and longevity, Tommy knows his stuff. For long-time listeners of my show,

you may recall that Tommy first came on the show back on episode 167. That was a fantastic episode that I would highly recommend if you have not listened yet, but you do not need to have listened to that one to enjoy this new one. We kick off our conversation with the empowering news that we can all improve our brain function simply by challenging ourselves more. We can make new nerve cells, new connections, and even change the structure of our brains. And it doesn't matter if you are 28 or 80. MRI scans prove that the brain can adapt at any age. Now, in our conversation, Tommy shares the critical importance of rest. He also goes through what exact nutrition our brains need to function well and grow. And we also talk about the role of B vitamins and omega-3 fatty acids for brain development

and the fact that there's no one size fits all when it comes to the optimum diet. We also talk about the similarity between training your muscles and training your brain and the research that conclusively shows that the more muscle mass you have and the more you move it, the lower your risk of cognitive decline. Tommy talks us through the types of exercises and the number of reps we need to do to gain muscle and brain benefits, and it's probably less than you think. We also cover the surprising value of video games, the importance of social connection, and why going to dance classes might just be the best thing you can do

for your brain and body. This is a fantastic episode, jam-packed with life-changing practical practical information. I hope you enjoy listening. And now, my conversation with Dr. Tommy Wood. I think that the common view in society is that as we get older, our brain function has to decline. What's your view? I think that it's true that it does on average. And you can see that multiple large population studies show that pretty much every cognitive function that you can measure decreases fairly linearly over time,

except for memory about the good old days. The majority of people seem to be able to remember the good old days, but every other, you know, the executive function, short term memory, all these other functions decline over time. However, I don't think it needs to be that way. Part of what I find to be very interesting about cognitive function and the way we think about it when we age is that there's this story that says you're born with X number of brain cells. And then every time you maybe drink a little bit too much or you don't sleep, you're killing brain cells. And it's just this inexorable decline that you can't change. And that's not true. that you can't change. And that's not true. We can make new brain cells in some areas of the brain,

particularly in some areas of the hippocampus, which is associated with memory. But even then, even if you're not making new cells, the cells you have can make new connections, you can change the structure around those cells in the brain, which is what helps support their function. And you can see that in multiple studies. Even as people get older, you give them a new challenge of some kind. You challenge their brain, and then they'll make new connections. Those areas of the brain will get bigger. You can see it on an MRI scan. So what I find interesting is that just like the muscles of your body,

which is easier to think about because you can visibly see it if you train it it gets bigger you can see strength much more easily but the brain is is very similar if you challenge it and you ask it to do new things it can adapt um pretty much any time in life so part of it is getting over this thought that um you know i'm old my brain doesn't work anymore, there's nothing I can do about it. So stop telling yourself that story and then introducing things to ask more of your brain and then it will function better. That's really empowering for us to realize that there are actually things that we can do. We're definitely going to get super practical and talk about a lot of those things. You mentioned that there are studies showing that various functions of cognition,

various functions of our brain, do start to go down with age. These studies that have been done, when have they been done? Because we know that there's a poor level of background health in the population. Metabolic health, cognitive health, all kinds of things. Generally, society is pretty unhealthy now in many ways. So therefore, are we just studying a sick society and seeing cognitive decline go down? Or is it something that's actually an inevitable part of aging in your view? Or is it something that's actually an inevitable part of aging in your view?

So until we get to the point where we can completely stop the aging process, which I think is unlikely to happen anytime soon, function will decline over time in anybody. How long that takes and what sort of the ultimate end of that, I think is modifiable and very much so. So there is going to be a decline over time, but you can change the trajectory quite dramatically. So that's where you end up. But when you ask about how these studies are done, I mean, I guess there's two different ways. One is you do this large population observational study so you you look at the cognitive function in multiple people of different ages and then you kind of see that

across ages as you look at older people their cognitive function declines uh you can do that in large populations uh in a smaller population you might be able to take the same people and look at their cognitive function over time um and or look at their you know future risk of dementia and that's and that's been done too um however when you're studying the population and in general these are studies done in modern westernized industrialized populations and we're at a stage where we have to say that those populations are on average unhealthy um. The vast majority have at least one of the components of metabolic syndrome. They, on average, take one prescription medication, on average have at least one chronic health condition.

So we know those various things that poor systemic health is associated with worse brain health and an increased risk of cognitive decline. So you're right, it's very difficult to study very healthy people and look at what happens to their brains because there just aren't very many of those people to study anymore. When we think about cognitive function, a lot of people are thinking about Alzheimer's. They're thinking about, I don't want to get Alzheimer's when I get older. Maybe they've got a parent or, you know, an auntie or a grandparent. You know, it is affecting many people's lives these days. They're seeing what happens.

So I wonder if you could explain, first of all, what is Alzheimer's And just compare that to cognitive function, because declining cognitive function, so declining brain function as we get older, is not necessarily the same as Alzheimer's, is it? What we call Alzheimer's disease is essentially two different diseases in my mind. The original Alzheimer's disease, as described by Dr. Alois Alzheimer is what we would now call early onset or familial Alzheimer's disease. It's caused by a single mutation in a single gene. There are a few genes that you could have a mutation in, we just need a mutation in one gene that causes early dementia, like 30s or 50s. So third to fifth decade of life, and has sort of like a steady decline and quite rapid.

And that's a huge genetic component. It's almost all genetic. And it's less than 5% of cases of Alzheimer's disease. So it's fairly rare, relatively. What most people think about when they think about Alzheimer's disease is what we might call sporadic or late onset Alzheimer's disease. It maybe occurs in your 60s to 80s or later if you live longer. And it's very heterogeneous. It's very variable from person to person. There's this old adage that says that if you've seen one person with Alzheimer's,

you've seen one person with Alzheimer's because it's like how it expresses itself in different people is very different based on their environment, their genetics, their lifestyle, their general health. And that second disease, I don't think is Alzheimer's disease, as he originally described it, they're very different. And you can you can look at them completely separately. So that we might call or I have called in a paper that I published with a colleague of mine recently, age-related dementia. And it's influenced by all the things that we just mentioned, and we could talk about that more. As you go into that, there is this period of cognitive decline. So clinically, you might call it mild cognitive impairment as a specific diagnosis.

And again, it's sort of like the prodromal period before frank uh dementia sets in but everything happens on a continuum so if you look at cognitive function over the life over the lifespan like i said it it's sort of from your 20s or 30s it on average steadily decreases um so these processes are happening are starting much earlier in life. And that's been described. These processes of maybe the brain atrophying, starting to lose cells, but also measurable changes in function. Some of these things you can see on scans. It might start very early,

but it takes a long time before you get to the point where your actual function is detectably decreased, if that makes sense. And the way I, again, liken it to physical function, and because, again, I think that's something that people can picture more easily. So if you imagine that whatever you're able to lift, say, on a daily basis, shopping bags, things like that. You can probably lift more than that, right? You have this headroom, what you have to do every day versus what you would be capable of doing. However, as function declines, eventually, your maximum capacity is what you're able to do

every day. And that's what we would call frailty, physical frailty, because you have no capacity for, so say if you stumble, you can't save yourself, right? You're going to fall over. Or if we're thinking about leg strength, your leg strength will decline to a point where getting up from a chair is as much as you can do, right? You have no headroom. And so that's what happens with cognitive frailty

or cognitive decline. You just don't have any extra capacity you know there's the brain can't do any more than you're asking of every day and eventually the you get to the point where the function isn't good enough to do your your daily tasks and then that's when you start to go down into dementia yeah super helpful and really really clear so as we progress this conversation, let's be really clear that when we're talking about Alzheimer's, we're not talking about the early onset, the classic Alzheimer's. We're mostly going to be talking about age-related dementia. This, I think, is what many people are quite

scared about. Certainly the older people get, and it's not uncommon now in people's 30s or 40s to go, man, I can't remember stuff like I used to, right? So I think everyone is aware of the kind of phenomenon we're talking about. Let's say people get a diagnosis in their 60s. When does it actually start in their brain? So it probably starts right after your brain finishes developing. So after you've built the brain, you've built the connections, you've put down the final parts of white matter in your prefrontal cortex that maybe happened in your 20s or mid-20s 30s that's that's when the decline starts so you you increase you build the brain you increase its function and then it starts to decline i don't mean that in a negative way

that is just when the process starts and part of that i think is driven by societal pressures rather than some process that we have no control over. Yeah. And what I mean by that is I to try and think about what a brain needs to maintain its function because I'm a neonatal neuroscientist. That's my day job. So I think about what does it take to build a brain in the first place and obviously you need you know the actual structure so you need the nutrients and the fats and the things that that make up your brain but you also need the kind of stimulus that it takes to build build connections and so think about babies and toddlers they're continuously exploring trying new new things, failing, building motor skills, tripping over, trying to stand, trying to climb trees. But they do the same with language. They

do the same with social skills. They're constantly pushing themselves, trying new things. And sometimes they fail. But they laugh it off and they just keep going. And then they do that for a period of time and then they sleep. They rest and recover. They need that for what we call consolidation in the brain for that period of plasticity where you're sort of building new connections. Adults don't do that.

We do the same things again and again and again. And part of what I think happens in your 20s and 30s is that you leave formal education, you leave that period of trying new things, learn new things, you know, learning how to drive, all of that's done. And then you become increasingly good at the things that you do every day, which isn't stimulating your brain in the same way. So I think we can build those things back in. But part of the reason why that decline happens

at that period of time is because that's the time when you stop challenging your brain to develop new connections and to maintain the structure that it has. Yeah, I mean, it's so beautifully simple the way you look at that when you look at kids.

Try new things, they're failing, they're exploring, they're experimenting, then they sleep. So giving it the stimulus you're giving it that new information so the brain adapts and then you're resting so it can grow stronger yeah and yeah as adults certainly as adults in the current society in which we live um we don't tend to do that. It's really interesting, Tommy, as you were talking and you were saying that that cognitive decline, that decline in brain function probably starts somewhere around our early 30s. And before you were talking about how our brain mirrors our muscle, well, we know that from the age of 30, we start to lose lean muscle mass

unless we do something about it. So there really is a very strong similarity, isn't there, between muscles and brain? The more I think about this and look at this from the societal down to the biochemical level, I think they mirror one another almost exactly. And it's the same with almost any tissue in the body. In particular, the thing about muscle tissue in the brain, it's very easy to draw lines across them, which is that the structure and function of a tissue is directly proportional to the demands you put on it, right?

The more you challenge your muscle, the more muscle you grow. But in order to grow, you need a period of rest and recovery. And the brain is exactly the same. And you can think about that in terms of building new connections, building new cells, but also processes of repair. So autophagy is this thing that people are really interested in now where you start to break down the accumulation of damaged proteins and other things within cells. And in muscle tissue, the best thing to do if you want to increase autophagy in muscle tissue is you exercise it, you move it. And it seems that the brain is the same, that stimulating the brain is protective because it upregulates these repair processes.

And so that then gives you this framework where you say, well, in order to improve the function and structure of my brain i need to challenge it but then i also need to give it everything that it needs in order to adapt to that challenge so that can be nutrients it can be sleep and recovery it can be making sure that there aren't toxins in your environment like we know air pollution is linked to an increased risk of dementia things like that which then may inhibit your ability to to adapt but the primary driver in my mind really seems to be like how much are we seems to be like, how much are we asking of our brains? And how much are we allowing it to recover? And that brings in a part of things around health equity, because not everybody gets to sleep. People working multiple jobs with

lots of family members in a small space, it's very difficult to sleep. Or being chronically exposed to societal stresses and that chronic stress is probably something that prevents adaptation because you don't get a recovery period. So you can start to see how all the things that we know are linked to an increased risk of dementia may be linked to, first of all, how much are we challenging our brains

and then how are we supporting it and its ability to then adapt to that challenge i want to get to the practical things we can do shortly earlier today i spoke to tim peak um british astronaut He spent six months on the International Space Station. And there's a couple of things in that conversation that I think really speak to what you have been speaking about. He spoke about the training process. He had six years of training. Now, in that training, there's all kinds of things they do. They put them in super uncomfortable situations. They're really trying to build physical resilience, psychological resilience. They take them to cold, dark caves. They deprive them of time. You see what happens when you are under that much pressure. So, they're being pushed out of their comfort zone to see how they respond. But he also had to learn Russian.

Now, I don't know how old Tim was, but that's interesting based on what you have said, right? Because I'm thinking, yes, he's been trained to be an astronaut. So, you know, teamwork, be resilient, deal with pressure. But actually, a lot of that training is also going to reduce the likelihood that he's going to get age-related dementia. What would you say to that? I'm sure that's the case. Other than the fact that microgravity or lack of gravity… I was thinking that as I said the question. Has an interesting effect, at least on muscle tissue.

And so how it affects the brain would be an interesting thing. But in general, from his time on Earth, yes, all of those things. Had he done the training and not gone to space, then that would be excellent brain training. But again, learning Russian, like we tend to learn languages at school because we have to. But that new paper you published which was wonderful like it's such a good paper and we'll definitely link to it in the show notes people can read it themselves you made a very strong case with your I think co-authors

yeah um that a lack of stimulus to our brain may well be causative. So not associated with, but causative of this age-related decline in brain function. So that's certainly how I read the literature. And so I published this paper with Dr. Josh Turkin, who's a neurologist. who's a neurologist and it's difficult to really unpick causation in humans to say you've really proven it and in fact it's impossible to prove anything in biology i think that you know people need to appreciate that however if you look across a broad range of animal studies, human studies, that's really, again, how it looks. And it comes down to how much you're challenging your brain and then supporting your ability to adapt to it. So it's not the only thing.

But again, to draw a connection back to muscle tissue, imagine you had the perfect diet and plenty of sleep and strong social connections all these things that we know are supportive of health um but you didn't do any exercise you were you know you were you sort of confined to your bed and there's been hundreds of studies done on bed rest or immobilizing a limb you know if you've broken your ankle and then you put your leg in a cast when you take that cast off the muscles on that leg have gotten smaller and or if you lay in a bed and you don't move your your muscles get smaller. So even if everything else is perfect, if you don't stimulate that tissue, it will reduce in both size and function. And the brain seems to be the same. I think one of the most interesting lines of evidence that supports the

idea is based around retirement. There are multiple studies in multiple populations that suggest that the earlier you retire, the earlier you get cognitive decline and dementia. And this is particularly in people who have cognitively stimulating jobs. In fact, then the effect is bigger there. And this is after you adjust for, you know, you might retire early because you have a medical condition that's also associated with there. And this is after you adjust for, you know, you might retire early because you have a medical condition that's also associated with cognitive decline. This is after you adjust for those things. You see this sort of rapid decline

in cognitive function when people retire. And that's because work is the thing that's most cognitively stimulating for most people. And then you remove that and you don't replace it with other stimulus. That's when you start to see that sort of inexorable or sort of faster decline in cognitive function. So for people listening, right, Tommy,

who either have retired themselves or are thinking about their parents, or we have a lot of younger listeners these days who might be thinking about their grandparents. Based upon that, they've retired, they've left their job. So what practical advice would you give to them as to how they can sort of make up for that lack of cognitive stimulus? So what's nice about this is that it seems that there are many different ways to overcome this, all of which are very likely to be effective. So you alluded to one of them, which is learning a language. And learning languages, even late in life, have been shown to improve cognitive function

and be protective for certain areas of the brain. Physical movement does it. There are randomized controlled trials that show that resistance training improves the structure and function of certain areas of the brain. So just going and starting to lift something, if you've never done that before. With respect to movement, it seems that you get more benefit if you do a movement that has some kind of coordination component. So you might think Tai Chi or yoga. One of the modalities that's best researched is dancing. So if you

have older adults in their 60s and 70s, and you make them do some kind of circuit training at the gym or the same amount of effort of activity but in a dance class instead, they'll get more cognitive benefit from the dancing. And actually, you can even see that on an MRI scan. Their hippocampus gets bigger more than the other group. And what's nice about something like dancing is that there's a music component, there's a social component, there's a movement component. All of these things we know

support health, both physically and mentally. So all of those things, I understand in isolation would be helpful. Music, social connectivity, very, very good for the brain, physical movement. All these things individually, I think, have benefits, but you chuck all three together and mix them up at the same time, then you're, you know, it's almost like a three-dimensional stimulus for the brain rather than just a one-dimensional one. Yeah, exactly. And there is some specificity in terms of what are you asking your brain to do versus what did it get better at. So when they've done studies of individuals that did a very challenging learning stimulus, the best example that I know of is taxi drivers who are learning the knowledge in London. So they took three groups or they ended up with three groups of individuals.

So for those who don't know, I guess people don't need to learn the knowledge anymore, but it's 25,000 streets, a six mile radius around Charing Cross Station in London. You have to learn to be a taxi driver in London. So it's a huge amount of things you have to like, I mean, just the memory component is incredible. And it took two years. So people who, and they did brain scans before and after.

And those who learned the knowledge and passed, they saw an increase in the size and some measures of intensity of connection of the hippocampus, which is the area related to memory in the brain. And these are adults in their 30s and 40s. Those who didn't manage to pass didn't see that. And then also they had a control group

where they didn't see any change. So this is specifically in those people who managed to do this huge learning task, saw benefits in that area of the brain. But then they saw a slight decrease in some other aspects of cognitive function because they put so much into memory. So if you really focus on one thing,

you become really good at it, but then maybe you've taken away some things from other areas of the brain, it's possible. So if you take something that gives you all of those at the same time, so you mentioned like social connection, the benefits of physical activity, plus the coordination component, plus music, I think there's multiple aspects of stimulus, there's multiple parts of the brain, but they seem to come together in a way that's, it's difficult to say if it's true synergy, which is that it's more than the sum of its parts, but definitely seems to be more beneficial

than doing any of those things individually. Just on the black cab London taxi example, which I think is a really beautiful one to think about. Certainly my experience, if I'm ever in London, is if you take an Uber and they're just following the sat-nav. You go to the black cab driver, they seem to go through all these crazy back roads and you get there quicker. So I suspect there's still something going on with that test there. But the wider point for me is, you know, we're talking about how society changes our behaviours.

Smartphones, GPSs, and our cars, right? So many people now have no real perception of where they're going if that sat-nav is not on. what do you think the consequences might be as we outsource more and more of our brain function to devices and technology i think as the way that you describe it there's there's clearly a possibility that it's going to be detrimental, right? We've offloaded all the things that our brain is really good at that make, you know, some of which make us uniquely human, and we've offloaded them, we no longer ask our brains to do those things. And if you don't ask a tissue to have a certain function, it will no longer have that function, right? It's the same with, you know, your cardiovascular function if you're running.

So I think that's definitely something we need to consider. But there's also the possibility that with the advent of new technology, we ask our brains to do different things and be good at different things. And that may also be just as good, right? So I noticed myself, because I mean mean i've access to huge volumes of information and for my job i need to know huge volumes of information and the majority of the time i probably don't remember all of the things that i could possibly need to remember and i

notice that what i remember instead is where that information is right so i still have memory of important things but i don't necessarily remember the exact fact but i know where that information is, right? So I still have memory of important things, but I don't necessarily remember the exact fact, but I know where that fact is. So when I'm preparing to do a podcast, I'm like, I know I need this piece of information from this paper, and I know who wrote it, and I know where to find it so I can go back and read it.

So I'm still requiring memory, but just in a different way, which I think is probably not not necessarily detrimental it's just different yeah and i guess you know thinking about what you said just before that that if you are putting all your attention on learning the huge amount of roads and back roads around charing cross station that takes up so much of your cognitive reserve that you have less available for other stuff. So yeah, sure, you're a great taxi driver, but maybe other areas of your brain have been neglected. I guess you could make the case with technology that, I don't know, let's say you're driving to a podcast to be a guest. instead of using up your cognitive reserve

on the way trying to figure out where we're going where's the street actually it can make it quite a stress-free experience if it's all working and you know things go smoothly which means that you have more cognitive reserve for the important activity that you're about to do yeah i think so um there is you know more and more evidence that suggests that you know you can't you don't burn more calories by thinking harder um but it doesn't require your brain doesn't require more or less total energy but there certainly seems to be reserves of things like you know willpower and decision making and you know access to cognitively challenging things that you can probably only do for a short period of time before you need some rest and recovery so if you're offloading difficult

but more menial tasks to something else that does give you greater capacity in theory to then apply that to other to other areas we. We know that the brain does not multitask. As much as we like to think that we multitask, people don't multitask. When you task switch from one thing to another, you end up wasting a lot of time as you adapt from one task to the other. So if you're in some deep period of writing and you just stop to check your email, it'll take several minutes when you switch back before you get back into the same flow of the writing that you were doing before. So being able to be more fully focused on one thing

because you offload tasks, say, to technology, I think could be very beneficial. And there were other tasks that maybe didn't exist 10 or 20 years ago or 50 years ago that now our brains are very good at so recently somebody asked me about video games and a lot of video games can involve you know reactions fine motor control problem solving um all these things that we we can sort of like be challenging our brains in in in in a completely different way from how we might have done 100

years ago. But that doesn't mean it's not beneficial. I think that's very beneficial. It's just different. Different. You know, what's really interesting on that, I heard over the past few months, you may know best than me, because I know you do some work with Formula One. I believe one of the current top drivers apparently was an avid video game player growing up. And actually, because of the way these cars are now controlled, hey, I'm no expert on this. This is just what I've heard from someone in Formula One.

That actually, there may well be a lot of transferable skills from your ability to handle a video game controller and your ability to drive a Formula One car. Just taking a quick break to give a shout out to AG1, one of the sponsors of today's show. Now, if you're looking for something at this time of year to kickstart your health, I'd highly recommend that you consider AG1. AG1 has been in my own life for over five years now. It's a science-driven daily health drink with over 70 essential nutrients to support your overall health. It contains vitamin C and zinc, which helps support a healthy immune system, something that is really important,

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end of January, they are doubling the five free travel packs to 10 and these packs are perfect for keeping in your backpack, office or car. If you want to take advantage of this limited time offer all you have to do is go to drinkag1.com forward slash live more that's drinkag1.com forward slash live more. That's drinkag1.com forward slash live more. One of the reasons why I said earlier that to some degree, maybe the challenge doesn't matter, like there's some specificity, but just increasing challenges on the brain may give you greater overall adaptability and function is because we know that formal brain training, so like computerized brain training, which is used

very frequently in adults with cognitive impairment or cognitive decline, because it's something that's very easy to standardize, systematize, easy to track. So it's often implemented in clinical trials. If you do this sort of abstract online brain training games, it translates over to better working memory, executive function, and sort of things that you actually need in real life. You don't just get better at the game.

You also get better at the things that you actually need in real life. You don't just get better at the game, you also get better at the things that transfer. So, of course, video games may be very similar to driving a Formula One car, but there is some, you know, just overall challenge increases overall function, which then does sort of translate to other areas. You mentioned the term executive function a couple of times in this conversation.

Can you just elaborate exactly what that means? In the simplest sense, the way I think about executive function is your capacity to make informed decisions about your behaviors in the moment, generally. And it's more complex than that. Maybe people have heard the old stories where we learned about different areas of the brain based on uh either soldiers getting very specific um damage to areas of the brain during war or that you know there's this very famous case where a guy got like a railway pylon that just like took out just his prefrontal cortex of his brain and that guy you know just said whatever he thought, and it was very vulgar and very impulsive.

And an executive function is essentially your ability to override those things. So, like, we all think stuff, and then there's a part of our brain that says, don't say that, right? It's a really bad idea for you to say that. Or, you know, you sort of have these, everybody has intrusive thoughts occasionally, you're like, well, what would happen if I just jumped out the window right now? I've randomly

had that thought, but executive function is, no, you really should not do that. So it's those things which require, and it happens just a fraction slower than the impulse, and it's your ability to control that and then sort of have some control over your actions yeah so executive function is clearly a higher brain function that we would want yes to maintain we don't want it to be declining yeah um you know she was saying that i was thinking you know if you look around on social media these days, sometimes you see comments and I'm thinking, you know, that's a public comment, don't you? You know, other people are seeing that. I mean, that's just like, well, I guess it's off topic, but is it? No, that's kind of, that's an element of executive function. I think so. And I guess there's two parts to this, right is that you know people talk about um the anonymity

of social media you know you could just say stuff because there are no repercussions right usually part of you deciding not to do something is because there's some social repercussion which in general on social media that there isn't um the other parts of it which i've read about um from mark banson who's just one of my favorite or my favorite pop psychologist, if you want to call him that, where he made the point that because of social media, you're exposed to the opinions of far more people than you would be otherwise. Right. otherwise, right? So 100 years ago, when you couldn't have online interactions with people you essentially don't know, you might have seen 10 people in a day, and you might have seen 100 people in a week. And some proportion of the population are probably people who are going to say things that you don't agree with, or just aren't very nice, right? But on social media,

you may be exposed to 1000 or 10,000 people a day,000 people a day if you've got a lot of comments on social media. So part of it, I think, is directly in relation to how you might behave differently in social media rather than in person. And part of it is that you're exposed to so many more people that some of those people are just going to be unpleasant and you're going to see that. If we get back to that family member who's retired, and so you were suggesting certain things that they could do to maintain that cognitive stimulus to reduce the likelihood that they're going to get age-related dementia in the future. I know we touched briefly on this in our first conversation, but I think it's worth going into again, Tommy. It's not about mastery, is it? It's not about being an expert. In fact, in some ways, you're better off doing something that you're not very good at. That's one thing I wanted to talk about.

And then I wanted to almost go from there to something practical for people, because let's say we're trying to reduce the rate of decline in our brain function. Something that I've been thinking a lot about over the past couple of years, maybe influenced by our first conversation as well, if I'm honest, Tommy, is what am I doing in the next five years of my life or in this decade of my life that is different and new and something I couldn't do in the last decade. And I think about this, I have this thing inside me that at some point in the near future, I'm going to take up martial arts because I'm fascinated by it. I've never done it before. I'll probably be pretty poor

at it when I start. But for my brain function, that's probably a good thing, is it? Yeah. And specifically related to martial arts. So there are multiple different sports where they've looked at this. But if you match the exertion level during learning martial arts versus some other thing like running, we can get the same cardiovascular workout, but there's no movement or coordination challenge or having to think about not being punched in the face

or kicked in the face or kicked in the face if you're actually sparring, you get a greater measurable benefit from the martial arts than you do from the running in terms of cognitive function because there's the additional challenge. The question you asked about doing things that you're bad at, I think is the perfect one because that then allows you to figure out the things that you might want to do in order to increase the sort of stimulus, prevent the cognitive decline that we talked about earlier. And one of the best examples that I have of that is a study that was done in musicians. And they looked at how old their brains

look on a brain scan. So you can do an MRI scan of the brain, and then there's this machine learning algorithm called BrainAge that basically says, how old does this brain look? You know nothing about this person, but how old does their brain look? And they did a study of musicians, and they had professional musicians and amateur musicians. And compared to the average population, all the musicians had brains that looked younger on the scan than they were in terms of their actual age and years.

So being a musician seemed to be beneficial regardless of what type of musician you were. But the amateur musicians had a greater benefit. Statistically, significantly younger looking brains compared to professionals because it's harder. If you're an amateur and you're not very good at it, then it's more of a challenge. That's what the conclusion that the authors came to. So there's an interesting conundrum here. For me, as I hear that, right, I'm thinking,

okay, so someone may hear this and go, all right, I'm in, right? I don't want my brain functions to go down. I'm going to learn a new language yeah so they sign up for a course or they buy a book or whatever it might be and they start learning that language and find out oh man this is really difficult oh god i can't do this is really really difficult i've got a few words i can't put it together in a sentence okay if they persevere with that that's going to be great for their brain function.

But I guess if they're not enjoying it because they're not good at it, they're probably not going to do it much. So, you know, help us understand practically what we should do in that situation. And that's absolutely right. So I think the process of learning and failing, developing a skill that you can probably only do in 20 or 30 minute chunks. If you think about a martial arts class, after you've warmed up and the warm down and the stretching,

like how much time are you spending learning new patterns, new movements? It's maybe 20 or 30 minutes in a class. If you do a language class, you know, after you've said hello to everybody and kind of got into it and opened the books and you know, you have a language class, you know, after you've said hello to everybody and kind of got into it and opened the books and, you know, you have a couple of conversations, how long do you really spend sort of pushing the limits of your language skills? It's maybe 20 or 30 minutes an hour, because that's really the period of time when humans can really sort of like push on the edges of their skill. So if you think about learning new skills, then that's kind of what you're thinking about. Something that you can spend 20 to 30 minutes, you know, really sort of exploring the limits of what you can currently do, getting a little bit better.

And that's it, right? It should be hard after that. And then, you know, you get frustrated or you get cognitively tired and that's when you need to rest and recover. What you choose to do that, I think, matters a lot less. Because of all the things we've talked about language we talked about movement you know it could be like knitting um it could be video games it could be online brain training all of these things have been shown uh to have benefit and so yes just doing something that's hard is going to be is going to be beneficial to a certain extent but if it's not

something where you can continuously go back to it because you enjoy it, then you're not going to stick to it. So it's the thing, it's a combination of something where you're learning over time and getting better, but also something that you enjoy because that's the thing that you're going to do more of. Yeah, so that's super practical for all of us, whether it's our retired parents or ourselves. It's like, what are we doing in our lives currently that is challenging and that we enjoy, I guess. And you're saying this sort of 20 to 30 minute period. Are there any specific trials on that? Or is that sort of an amalgamation of other neuroscience research that means, yeah, we kind of think it's about this time yeah it's it's probably um at least partly related to you know focus and attentional capacity and in other areas you see

something you see something similar so i'm i'm stealing ideas from say the pomodoro technique which is where you have uh 20 or 25 minutes of focused work rather than a five minute five minute break where you completely detach yourself because 20 minutes is is the period of time where you can really focus on something and and devote yourself to it before again your mind starts to drift or you go elsewhere and then if you think about well in scenarios where we're teaching people new skills you know of course you're usually trying to fit something into an hour because that's just the standard unit of time. But in general, how long are people really working on these things?

And it seems to be something like 20 to 30 minutes. So part of it is practical, but then part of it is based around, on average, that's the period of time when somebody can really focus on something. Crosswords, Sudoku, do they help? crosswords sudoku do they help i don't my guess is a little bit but probably not nearly as much as any of the other things that we've talked about um purely because there just isn't that kind of there isn't that kind of challenge or skill in the same in the same way. Maybe cryptic crosswords are their own separate, because there's a skill around cryptic crosswords, right? You need to know what the clues are

for what you need to do with either the words or the letters in order to get the final word. A traditional crossword is usually just memory. And yeah, that can be useful, but it's not that same kind of challenge. And then again, once you're good at it, so once you're really good at cryptic crosswords, it's probably not the same challenge anymore.

Once you're really good at Sudoku, it's probably not the same challenge anymore. And people often like to do those things because it takes five or 10 minutes, it passes some time, it's nice to complete something, but then you're in some area where it's not really the same kind of challenge.

So maybe, but probably not the same way as some of those sort of more all-encompassing skills that we've talked about yeah i love this tommy it's it's super practical i know we spent a lot of time on this kind of um how are you stimulating your brain in a new way in a novel way that's challenging we'll definitely talk about food and sleep and movement and stress and that stuff. We're definitely going to get to that. But I think it's worth, I think it has been worth really hammering home this point. In terms of looking at what we can do to prevent our brain function going down with age, I love the way that I've heard you think about this before. I say the reason we know what to do is because we know how to create cognitive decline in animal models.

And I thought that's a really beautiful way of us looking at it. So perhaps you could explain your framework and then we could see where we're up to and where else we need to go sure so again like i mentioned earlier uh in my day job i'm a neuroscientist and the vast majority of that is doing work in animal models of brain and brain injury and brain disease neurodegeneration i think what you see is that we are from those models and and what's nice about those models you can isolate a single thing so i've been talking i've been having conversations about this recently in relation to, you know, what do you need? You know, what's important for cognitive decline? What's causative in humans?

And I've had some conversations around the work of David Smith, who's a emeritus professor from Oxford, who ran, you know, groundbreaking trials showing that if you give B vitamins to lower homocysteine in humans who have elevated homocysteine, you can slow the rate of brain atrophy and cognitive decline, like just with a simple multivitamin. And then there's an interaction with omega-3 status as well. So nutrition, incredibly important. But then there's a question of the homocysteine which is the thing that you measure to decide whether this person needs this supplement or not um is the homocysteine damaging itself or is it just telling you something about this nutrient deficiency um and that's a question that we can't answer in humans because you can't dissociate the marker the thing itself from what's

causing it to be elevated yeah You can do that in animals. I don't think it's been done in a way that sufficiently answers the question that I have, which is that, is it just the B vitamins? Or does the high homocysteine itself have a causative effect on cognitive decline? And some people think yes, and some people think no. But that's a question you can only answer in animals. But more broadly, you need, answer in animals. But more broadly, you need, you know, there are essentially three different ways that you can create cognitive decline in animals. And that's not doing genetic manipulation. That's kind of, I'll keep that separate. Assume that you just have an otherwise healthy rat or mouse. You can decrease the supply of things that are important for the brain.

And you can do that in two ways. You can either decrease the amount of those things being around, so nutrients being one, we just talked about some. Or you can decrease the flow of blood and oxygen to that area of the brain. You can create like a chronic decrease in blood supply to the brain. And so you're either not providing enough of the nutrients or those nutrients aren't able to get there. That's one thing.

So on that one thing, for a human, that's a poor diet, not getting enough nutrients in to supply the brain, or it's having, again, a non-scientific term, but furred up arteries so that, you know, you can't deliver as many of those nutrients that you may be taking in to that part of the brain. But that's all part of that first thing that you can do to cause problems. Okay. So yeah, so any kind of vascular supplies that could be, and it can happen in the arteries in your neck, arteries in the brain, and it's usually, you know, it's the same kind of process that happens in the arteries in the heart.

It might lead to a heart attack. Can we just pause on that a second, Tommy? Because a theme, I think, throughout this conversation is that you may not get the diagnosis of age-related dementia or Alzheimer's until you're 65 or 70. Alzheimer's till you're 65 or 70. But the process that leads to that diagnosis may well be starting in your 30s or your 40s. I know Professor Dale Bredesen, who I've spoken to before on many occasions, the neurologist in America, I'm pretty sure he said, you know, this starts at least 30 years beforehand in the brain. Yeah, exactly. So I think that's a key point. So we're going to talk about diet shortly. And also in terms of nutrients getting up,

again, people may be familiar with strokes or heart attacks, where that's a very late stage when actually you've got problems and symptoms. But many of us probably, without realising, may well have degrees of furring well before that yeah and so everything happens on a on a continuum and you can yeah you might have this you know acute very acute change or lack of blood flow that's what we would call a stroke an ischemic stroke but you can also just have um and it may not even be right if you had a a scan on your arteries you may not even see

that there's this huge blockage or anything like that but over time again as your vascular system you know your your blood vessels as they age and that's related to a whole bunch of these very similar things um they become more stiff and when they're more stiff they it means that they can't regulate themselves the way they normally would and we we do this process in the brain called neurovascular coupling which basically says that when a neuron is more active it asks for more blood flow right i'm gonna and the muscles do the same right when you work your muscles harder your body diverts blood to those muscles and the brain should be the same way but over time the blood vessels may not be able to do that so when the brain is asking for more oxygen or is asking for more nutrients the vessels don't respond um so that's so that's kind of one

thing you're not getting enough of whatever it is you need to the to the point then another way is to provide some kind of chronic for one want of a better word, toxic exposure. This is the second way to damage your brain. This is the second way to create cognitive decline in an animal model. And you can poison very specific parts of mitochondria or other things. So they've done it with very small doses of cyanide.

But you could equally do it by by exposing uh an animal to um like car exhaust um you know sort of more common things that that we know are part of the environment and so those things essentially inhibit either energy production or the ability of the the cells in the brain to to to respond or or adapt or maybe directly damaging. So toxic exposures, so it could be cigarette smoke, it could be car exhausts, it could be heavy metals and fish. So heavy metals and fish, so potentially mercury, although if it comes from fish, the selenium and the omega-3s and things like that in the fish may protect us yeah may

protect us and sort of overcome any any detrimental effect there uh but something like lead seems to be um you know and it's very common in some water supplies even in you know industrialized countries so for years it was in the paint yeah yeah in the paint in the pipes i mean we're in in so that was part of air pollution right because of leaded petrol of course i mean we're in in so that was part of air pollution right because of leaded petrol of course i mean we're only two into the three ways in which you can cause actually a fourth i forgot it's actually there's a fourth right so only two of the ways in and i'm already thinking about what you said at the start about the societal pressures and you know poor nutrition poor lifestyles um air pollution right it's no wonder when we currently

study populations like there's a linear decline in in our brain function yeah so with all the good news let's go for let's go to number three it's lack it's lack of stimulus right so we've already talked about that in multiple ways but if you um the way that we would do that in animal models um is we either socially isolate an animal which is incredibly stressful and you have to get um what's interesting and it's important it's incredibly important for doing high quality animal work that's ethical and that actually helps us move human health forward which is ultimately the goal if it's not doing that i don't think it's worth doing.

In order to do ethical animal work, you have to look after those animals as best as you possibly can. And one of the ways that that's ensured is, there are committees at every university that make sure that every experiment that's proposed is as ethically sound as possible. But unless you have a really good reason to, there are two things you're not allowed to do you're not allowed to socially isolate the animal and you're not allowed to remove any stimulus from the environment what we call environmental enrichment and that can be in

terms of uh like a running wheel for mice or it could just be like toys or something in the cages um and if you think about humans socially isolated isolated, lack of cognitive stimulus, like we're doing this to vast proportions of our population, particularly as they get older and we've taken away social connection, we've taken away stimulus. You're not allowed to do that to a rat in a lab unless you have a very good reason for doing it. But you can do it to a human, no problem. That is, just to look at it through that lens is completely nuts isn't it yeah

wow so that's that's the third part and then the fourth part we kind of talked about a little bit as well which is that well you need the stimulus you need the things that require nutrients to respond to the stimulus you need the absence of toxins and then you need some kind of period of rest and recovery so that's why sleep is critical. But then also absence of chronic stress is probably something you could put into that bucket as well. And you can do this with social stressors, say, if you're going to do this in an animal model. So we talked about social isolation.

That's a chronic stressor. But you can also do it with aggressors. So you might have an aggressive mouse that you introduce into the cage and then that continuous aggression, which could be discrimination based on your physical ability, based on your race,

based on your socioeconomic status. You know, these things that people are exposed to again and again and again, we might model it in that way. And then that's, you know, there's a whole host of physiological immunological you know things that we can measure that result from that but you know cognitive decline and chronic health conditions can be one of the things that come from yeah i'm thinking of that aggressive boss that aggressive family member but the sort of thing

we can all think about in our own lives, whether currently or previously, and what an impact that can have. And it also speaks to what you said early on in the conversation. And it's something we have to be super conscious of when we're talking about making changes to improve the quality of our lives. You know, I'm all like you for empowering people with helpful information. But I think we do need to acknowledge, maybe in this wellness community, more than often does get acknowledged, that there are huge psychosocial stresses, cultural stresses for different communities, financial stresses, racial stresses.

These things hugely impact our biology and our physiology. And for some of us, it's easier to make those changes than for others isn't it yeah and i think it's uh it's been something that's sort of aimed at uh whether you you know the lifestyle medicine or functional medicine or integrative medicine uh ancestral health communities you know there's people who focus on these lifestyle factors that we've talked about and it's a worthy criticism criticism to say not everybody can do that right not everybody has the financial ability to remove themselves from the

environment that they're in if it's you know um they have to live close to a road or they have to live close to uh refinery right so in the in the united states um you know near you know large petrochemical plants that's where you've had redlined housing areas where people from low socioeconomic status usually more likely to be black have been put around these areas and then it's you know it's baked into the environment and you can't afford to move out um and or it may be you know we talked about food but you know what food do you have access to um do you even have a kitchen you know do you have are you working two jobs do you have time to cook um you know we need to be very mindful that the social determinants of health play a big role here yeah i mean i totally agree with that i think it's i think there's a lot of nuance to that because sometimes that criticism gets leveled and say we

shouldn't be giving any information out because it's not relevant to that community yeah i don't agree with that it's like we should definitely be giving any information out because it's not relevant to that community. I don't agree with that. It's like, we should definitely be giving out information, but we also need to be aware that that information may not be relevant or as relevant. And so we shouldn't look down when people can't take that advice, for example. You know, and I've always fought for that wellness, for want of a better term, is for everyone. I think every single human being has the right to good quality health information that they can try and apply in their own life. And my bias comes from my clinical practice. So I've worked in lots of different practice throughout my career, but there was a particular period of time where I worked in a practice in Oldham in North Manchester, and it was a very low socioeconomic

status area. Lots of immigrants, lots of people on benefits, people working two jobs, lots of single parents. A lot of, in adverse commas, struggle for day-to-day life compared to other areas I've worked where it's more affluent. There's struggle there as well in a different way. And you know what I learned, Tommy, in that? Because I think it's easy, and I see this in the media a lot, it's either we can empower people with their lifestyle choices, or we say that there's huge social determinants of health. It's kind of like, well, why does it have to be that black or white? I think all these things are nuanced.

And I do passionately believe that this information is relevant for everyone and we should be giving it to everyone. But with the acknowledgement that for some people it's harder. Yeah, and I completely agree. And in that line, I think it's very both patronizing and disempowering

to say that, oh, you shouldn't be talking about lifestyle or diet because it's, you know, these people, you know, may or may not have an ability to change that. It's very condescending. It's incredibly condescending. But we just need to acknowledge that all of these things are important. But again, there have been, there was a recently published study that came out in Lancet Public Health a few years ago that looked at, using UK Biobank data, looked at mortality risk, and they stratified individuals by some lifestyle factors, so based on quality of diet, whether they smoke, physical activity,

and then also stratified them by social deprivation. And you see that, yes, as your socioeconomic status decreases, overall risk increases. But when you look at the effects of lifestyle, movement, diet, there's still great benefit there. So yes, the overall risk is greater, but there are individuals there

reducing it through those activities. So to say that we shouldn't be talking about it, I think is incredibly condescending. And also, what I found, Tommy, is that if I change the advice I give them, because I make that assumption, I'm depriving them of good quality advice. And what I learned there is actually sometimes in the poorest communities, they would actually literally follow my advice to the letter more than in more middle-class affluent communities. I remember I thought there wasn't much money in the family. And at the time, I don't think we

were allowed to give vitamin D. This lady had really bad pains and I was convinced it was related. And she went and bought from the local health food shop supplements for her and her family and got huge improvement. And it's unfair to think that we know what they will prioritize with their money. It's not up to us. This is complex, but I think it's important that we talk about it, actually. Yeah, absolutely. All of these pieces, different parts are important for different people in different amounts and um there's you know part of it is just getting information out there and and so again empowering people to to know what may or may not be important uh for them for and it could be whether they're worried about their risk of dementia or heart disease or you know

they just want to be able to play with their grandkids uh you know often people's goals are much more practical than a doctor might think. You're worried about some diagnosis or something, but people want to be able to just interact with their family or something like that. And different things are going to be of relative importance for different people,

but they should be allowed to make those decisions. Yes, I think that we need greater support for behavior change for individuals who want it. We don't necessarily do a good job of that. And doing something new that's stimulating and challenging, there are a lot of low-cost ways to do that, if not free ways to do that. Balancing, hopping around your, you know, I don't know, we could make up all kinds of things that would actually provide a stimulus.

Yeah, absolutely. And so I think that's a great piece of practice advice. Okay, so that was in the first bucket. The second bucket was about important nutrients not getting to the brain, whether that because we're not taking them in, or because we're taking them in, or we might be taking them in, but they're not able to get to where they need to get, because let's say our blood vessels are in poor health for whatever reason. So you've been on a bit of a journey, Tommy, since I've known you and from what I've seen in public. As we have this conversation in 2022, what is your current viewpoint on nutrition for human health uh i guess specifically we're talking around brain health preventing cognitive decline as we get older which i think everyone wants what kind of advice would you give to people regarding foods Before we get back to this week's episode, I just wanted to let you know that I am doing my

very first national UK theatre tour. I am planning a really special evening where I share how you can break free from the habits that are holding you back and make meaningful changes in your life that truly last. It is called the Thrive Tour. Be the architect of your health and happiness. So many people tell me that health feels really complicated, but it really doesn't need to be. In my live event, I'm going to simplify health. And together, we're going to learn the skill of happiness, the secrets to optimal health, how to break free from the habits that are holding you back in your life, and I'm going to teach you how to make changes that actually last. Sound good? All you have to do is go to drchatterjee.com forward slash tour and I can't wait to see you there.

This episode is also brought to you by the Three Question Journal, the journal that I designed and created in partnership with Intelligent Change. Now, journaling is something that I've been recommending to my patients for years. It can help improve sleep, lead to better decision making, and reduce symptoms of anxiety and depression. It's also been shown to decrease emotional stress, make it easier to turn new behaviours into long-term habits, and improve our relationships. There are, of course, many different ways to journal, and as with most things, it's important that you find the method that works best for you. One method that you may want to consider is the one that I outline

in the three question journal. In it, you will find a really simple and structured way of answering the three most impactful questions I believe that we can all ask ourselves every morning and every evening. Answering these questions will take you less than five minutes, but the practice of answering them regularly will be transformative. Since the journal was published in January, I have received hundreds of messages from people telling me how much it has helped them and how much more in control of their lives they now feel. Now, if you already have a journal or you don't actually want to buy a journal, that is completely fine. I go through in detail all of the questions within

the three-question journal completely free on episode 413 of this podcast. But if you are keen to check it out, all you have to do is go to drchatterjee.com forward slash journal or click on the link in your podcast app. I think the starting point is that you should eat something that is accessible to you, that you enjoy and is sustainable. That has to be a starting point because I could give you a whole bunch of recommendations, but if it's none of those those things then you're not going to do it or not going to stick to it and one thing that constantly fascinates me about the human body is how adaptable it is um and the wide variety of diets that people evolved while eating or you know ancestrally you know the the different diets that you know my ancestors

ate a very different diet to your ancestors because of where they are on the planet and they both thrived and i find that fascinating and so it's the same thing now like what somebody enjoys and is sustainable to them is very different from the person next to them and they may sustain their health in an identical manner with objective measures that you could take. So I don't have any particular one way that I would recommend that people eat, but it should support your health. And we can certainly talk about things

that you might measure and want to track over time. Specifically for the brain, because we have interventional studies that show it's the case. B vitamins are incredibly important. So we're talking B12, which generally you can only get from meat and animal foods. If you are vegetarian or plant-based, I think the best people who promote or work with individuals of those diets would recommend you take a B12 supplement. Then folate, B2, which is riboflavin, and B6. Those are probably the most important nutrients for brain health. And again, any diet that has a

reasonable number of whole foods, plants, vegetables, eggs, meat, fish, will have enough of those, probably. Then the other important thing specifically for the brain is the omega-3s, long-chain omega-3s. And in these studies I mentioned earlier by David Smith, they showed that the greatest benefit from the B vitamin supplement came from those who had what they called adequate omega-3 status. And again, these long chain omega-3 fatty acids like EPA and DHA, which in the diets are generally only available from seafood. But there is a slight genetic component based on people who can take shorter ones that you might get in chia seeds or walnuts and then convert them to longer chain ones um but so again there's there's a slight genetic component there but some seafood is probably important as well yeah okay this this is super interesting so you first mentioned b12

and as you say if people are eating animal products in their diet, they're likely to be at least taking in enough B12. What I've found, I want to use some measure of this quite a lot, is that even people who were taking in reasonable amounts of B12 had suboptimal B12 levels on their bloods. There's a whole variety of reasons why that might be. I have my view, I feel, I certainly feel stress is a huge part of it, because to be able to actually absorb that B12, what needs to happen can be impaired, I think, by too much stress. Because I was thinking, why is it that they're eating enough B12 from what I can tell, yet that's not being shown up? And there's all kinds of reasons for it, that's just one of my views i mean what's your perspective on that is that something you've

seen and do you have any opinions as to the reasons why that might be yeah absolutely and i i remember even um you know 10 years ago uh which is now 10 years since i worked as a doctor pretty much uh as a junior junior doctor at St. Thomas' in London. I was working on the elderly care ward. And when people got a first diagnosis of dementia, even then one of the first things we did was something called a dementia screen, which we looked at iron status, vitamin D, and some B vitamins, B12 and folate at least. And then if B12 was low, there was a second test they called methylmalonic acid, which is produced when you're B12 deficient.

And so even then we were doing it in an NHS hospital 10 years ago. Just these basic nutrient status checks. And I think stress certainly may affect acid production, which is really important for B12 and also iron absorption. But then some medications can do it. So metformin can affect B12 absorption, proton pump inhibitors, which people might take for reflux, that can affect B12 absorption. And these are very common drugs to prescribe. So there's probably some lifestyle factors, but then it may also be a result of something else that somebody's taking. Yeah, I remember probably some lifestyle factors, but then, you know, it may also be a result of something else that somebody's taking. Yeah, I remember Professor Bredesen, when I spoke to him about this a few years ago,

he will work with his patients to do all the tests, the homocysteine, the MMA that you mentioned, and the serum B12. And at the time, I remember thinking, I can't get this stuff in my NHS patients back then. time I remember thinking I can't get this stuff for my NHS patients back then and he said he likes to see for cognitive function a serum b12 right so that's your regular cheap uh b12 test um and you know I'm going to say it depends on your lab but you know the normal value that will be reported would typically be something like 200-250 to 700-800, maybe 900, depending on the lab. So huge, huge range of normal. And he said in his experience, if it's under 600, he would treat it. And I remember I came back because I was chatting to him in America,

and I tried that with a few patients actually. And again, this is just anecdotal. It's not a scientific study, but people would come back and say, yeah, they feel sharper, their cognitive function has got better. When I'd treat their serum B12 from, let's say, a normal level of 250, what do you think to that? I think that's, I mean, I'm not necessarily surprised. Again, it probably depends. What's interesting about the difference between the US and the UK

is that in the US, you can't get an active B12 test, what we would call holotranscobalamin. It's very common to do in the UK. You can't do it in the US. So on the US test, you probably need to be at the upper end of normal because there are lots of other things that can cross-react with the test and they look like B12 but they don't have the function of B12.

And that's the case with some plant-based B12 analogues. So for him, I imagine that's probably one reason why that may be the case. But equally, more broadly, I spent a lot of time looking at and thinking about blood tests. And if we think back to what we said right at the beginning, which is that the average adult has at least one chronic condition, takes at least one medication, has at least one, if not two, of the components of metabolic syndrome, of which there are five.

If that's the average person, and the normal range is just, the way you define the normal range is you test a whole bunch of people and you take the middle 95%, and whatever the bottom, the lowest person of that middle 95%, and whatever the top person is,

that's the normal range. And if the average person is sick to some degree, then what's normal is not necessarily normal. And I think that's part of it. And you see this again and again. They've changed the ranges over time. That's been the case for certain sex hormones. And people have talked about this a lot you know they're decreasing the normal range for

testosterone in men because they think that testosterone is decreasing uh on the population level whether it's actually true or not is up for debate but there's something that's happened that's you know they've changed the ranges if they see that you know overall the population level changes i saw something similar when they were trying to develop normal ranges for grip strength. And what they saw over generations from Generation X, Generation Y, Millennials, coming through to what in America we call Gen Z, grip strength was declining particularly in males so there was a publication that said that and said we need to change the normal range for grip strength rather than saying we're getting weaker why aren't we working on that and so you know it's it's like um the the frog that sits in water from when it's cold and if you if you boil it it will slowly heat up it will never jump out because it

never realizes because it's so incremental and slow and so that's that's one of the problems is that we're looking you know some normal ranges are constructed around a population that's sick so the normal isn't necessarily isn't necessarily normal and that's that may be playing part of the role there too yeah it's it's super interesting hopefully we'll get time to go into some blood tests that people can do you mentioned. Why do you think seafood is so important for our brain health? And then for people who are vegan or choosing not to have animal products, can they still have good brain health and get those nutrients that you would get from seafood in other ways so there are a few strands um then the of information that lead me to think that that seafood or i say seafood because it's the the most common dietary um component that gives

us long chain omega-3s what i'm really interested is long chain omega-3s. What I'm really interested in is long chain omega-3s, particularly DHA in the brain. And again, if I go back to what does it take to build a healthy brain in the first place, DHA is preferentially sucked up into the brain while you're making it, as much that the mother will sacrifice her own DHA status so that the baby gets enough. Because it's one of the most critical fats that makes up the brain for a number of reasons. Um, it, and it goes, it goes directly into the, the cell membrane. So people may or may not know that most of your brain, which is in water, it's fat, almost all of it, right? So, cause fat makes up all the insulation around the nerves. It makes up all the membranes around the cells and dha is incredibly important both for the function of the

synapses how they talk to each other because of its because of the because of its structure it has this you know very important um role in terms of like how the synapses work how neurons talk to each other but then it's also accumulated into the mitochondria which people might know as the powerhouse of the cell it sits inside the cell generates most of the energy and some of it is really cool physics that basically how electrons travel through dha is really interesting um but equally you know it's sort of like a more basic way you can see that the more dha that's in a mitochondria the greater energetic capacity it has the more energy it can produce um and that's the reason why and and there are some evolutionary theories that say that you know maybe the human brain as it currently exists developed in a sec in like a

group of hominids that had either direct access to lots of seafood or to the brains of other animals because brains are an incredibly rich source of DHA because your body preferentially shuttles it to the brain during development. So it has this really important functional role. And when you don't have it as associated with neurodevelopmental disorders or developmental delay um risk of other neuro like neurodevelopmental issues um and then you can also see things like um there have been some interesting studies done in the uk and in the seychelles where uh you look at the the amount of seafood that a mother or her her children eat and then you look at long-term neurodevelopment and you you asked about heavy metals earlier particularly mercury is important for seafood.

But it seems that even if you have a higher mercury burden because you eat a lot of seafood, you get greater benefit because of the omega-3s in the diet. So that sort of first principles approach says, what does a brain really want when it's developing? And it really wants DHA. It's essentially, that's where all your dha goes is your brain and again one of the things that um is interesting about humans is that we're the only mammal that has fat babies no other animal has fat babies and one of the reasons reasons why human babies are fat is because they have adipose tissue as

a store of DHA for the brain as it grows. When you say fat, you don't mean unhealthily fat. No, I mean like healthy, chubby, plump little babies, right? So if you look at any other mammal, when they're born, they're very lean, even other primates. They don't have large adipose stores. And so it's an energetic store, right? We know that adipose tissue, fat tissue is a store for energy. But it also stores fats that are then particularly used to the brain, and DHA is one of them. So a developing brain needs it.

Yes. Can we therefore say that a developed brain also needs it so this is an exceptionally nuanced topic even more so than any of the other topics that we've talked about a colleague of mine dr rory heath and i wrote a paper recently about dha and alzheimer's disease and some people have said that the dHA in patients with Alzheimer's disease in their brain is low. Others haven't quite found the same thing. Part of it is probably that, again, your adipose tissue is essentially a very nice buffer of DHA that you can use across your lifetime. So it's quite, if somebody is, unless somebody has never eaten seafood or has never eaten really any long

chain omega-3s, it's very unlikely that you're going to be deficient for the brain, for cardiovascular function and other things that may not necessarily be the case. And that's why the omega-3 index or your omega-3s in your blood is an increasingly used risk predictor of cardiovascular disease and things like that. So it's very nuanced. But if you're going to be maintaining cell membranes and cell function, you're definitely going to need some. And then the much better line of evidence comes from systemic measures of omega-3. It's impossible for me to measure how much DHA is in your brain, right? But I can measure how much is in your blood. and when these studies were

done at oxford they showed that you needed both adequate b vitamins and enough omega-3s in order for you to get this slowing in in brain atrophy and cognitive decline so if you measure omega-3 levels in people and they're low they have a faster rate of cognitive decline, which tells me that that's important because if you fix it, then you can change that. Yeah, it's super nuanced, but it's super important because, you know, tell me one of the things that I've noticed is I have seen patients thrive on radically different diets. So I'm like, there is no one true human diet that's for everyone, in my view. It's just based upon 21 years now of clinical experience. It's like, I've seen nothing to back that up.

There are some principles, whole foods, as much as you can, minimally processed, decent amounts of healthy fats. There are some basic principles, but you can twist it in many different ways, culturally, ethically, taste preference-wise, using those principles to seemingly be in good health. So I completely agree with everything that you you've said and i've also seen people thrive on an incredibly wide range of diets like i said earlier i think that's one of the most fascinating things about humans and we have to take individual health into consideration and so lots of things are done at the population level that are very important but if two different

individuals can thrive on very different diets and it supports their health in objective ways and they feel good we have to be able to support them and and in doing that um and to go back to omega-3s like i don't if you don't want to eat seafood there are algal um sources of long chain omega-3s right so you can do plant-based versions absolutely and you would recommend that to people? I would recommend... So I don't want to show up and just say people should take all these supplements. Ideally, you'd test, right? It's not difficult.

I mean, in my perfect world, you would have access to this test through your doctor. It shouldn't be something you have to pay for because it's much cheaper than you getting a whole bunch of cardiovascular and cognitive diseases because you just didn't know that what you needed was a bit more omega-3. So you would do one of those, what, blood spot tests? Yes, you do a blood spot for an omega-3 index.

And if you're in a good range, then don't worry about it. So I think that's really empowering. It's like, look, if you're choosing to eat predominantly plants, you're choosing not to eat animal products, and you're maybe thinking about what Tommy just said, another guest has said in the past, thinking, okay, well, why don't I just go and measure my levels? That seems like a pretty practical approach to take.

Yeah. And there are some studies that have been done that have looked at the omega-3 levels, the DHA levels of omnivores versus vegans. And sometimes vegans have lower levels, but there have been studies that showed no difference, right? So you can eat a plant-based diet and maybe you don't have any issues whatsoever. One thing that's interesting is that there may, you know, I don't at this point believe in nutrigenomics, where you can measure your, you can, you know, get a genetic test that will tell you the foods that you should eat i don't think

we're at a point where we can do that but one of the things that we know the most about is how our body metabolizes specific types of fats and there have been there have been some studies that showed that if your ancestors became agriculturalists longer ago, so they were usually close to the equator, usually became farmers further away in our ancestral history, like more thousands of years ago, then the body has adapted to being able to take shorter omega-3s, like ALA, which you can find in nuts and seeds and some grains,

and then turning it into these longer chain ones. By comparison, say half of my family is from Iceland, you can't grow grains in Iceland. There's not a starchy carbohydrate to be seen anywhere. They ate seafood and they still do, and that was where they got their omega-3s. So their bodies never had to adapt to it. So there may be some people, and one of the reasons why they thrive

on a completely plant-based diet is because they're really good at converting some of these precursors to the longer chain omega-3s. And that's partly based on their ancestry and some other genetic components. So that's why I don't think that everybody who eats a plant-based diet should take an omega-3 supplement.

I think they should test, and then if they need to change something, they should. But if they don't, then great. Yeah. Something potentially so simple has become so complicated because for years we would have just had our nutrition dictated by geography, climate, by culture, what our parents and grandparents fed us. You know, what was really interesting to me, I went to Greece this summer

and we were on this island called Ithaki, beautiful islands. We'd been in Greece for about 10 days at this point. And we'd been enjoying chill out time, my wife, myself, the family, we'd been enjoying Greek foods. But most of the vegetables we were getting served were aubergines and tomatoes, like literally every day. And we were at this restaurant in Ithaki. And I remember, I think the kids fancied and i said to their i think she owned the restaurant she was serving us i said hey um you know do you have any like other vegetables at all like i don't know broccoli or something else and i've learned so much tommy because she just looked to me baffled and she just said no they're not in season. And I thought, isn't that interesting?

She couldn't even fathom what you want to eat something that's not in season. Like it didn't compute. And it was really lovely, actually. It really made me think about how by having access to different foods three times a day and seven days a week, we can eat something different. I don't know. Any comments on that at all i think more broadly it's very possible that in the future we'll figure out the perfect human diet we can engineer it down to like the micronutrient and

the exact level that each individual needs for each you mean the personalized diet for each person at some point in the future that may be be possible. But right now it isn't. And so where I think we should get a lot of our information around our diet are those things like what's seasonal, what was available to us in recent history. And then, yes, I think you should also take advantage of modern medicine and test the things that you should test. And there are objective measures that we can take for our health from blood tests or colonoscopies and all these things. There are these things that we can

take advantage of. If your diet is supporting your health and or you feel great and everything is going well, I see no reason to change it. And I think that's what's really critical. Yeah, why would anyone change their diet when they're thriving? Yeah. Whatever it is. Whatever it is. And one of the hidden, one of the unintended consequences,

like I want to talk about gut health with you because you published, I read it today. It's a brilliant, brilliant paper. I think it was in 2021. Did you publish it? Yeah, last year. Yeah. One of the other things I've been reflecting on over the summer is gut health. We didn't know about this organ really on a big scale, maybe 10 years, maybe 15 years ago. It's pretty new. What are we missing? And in particular, Tommy, you mentioned some of your friends who are eating maybe what might be termed a carnivore diet these days, and they're seemingly thriving. I'd had Tim Spector on in July. And I mentioned to Tim,

because Tim was talking about gut health and talking about 30 plant foods a week. And I mentioned, and I've got patients like this, I've got friends like this. One particular friend of mine who I spoke to Tim about, I said, Tim, but I've got a friend who has tried everything. She used to be paleo, she was vegan, She was raw food. She's very educated on health. She's a practitioner. And about five years ago, she pretty much moved to close to carnivore. And I don't know many people. She's in her 50s. She is thriving. She looks great. She can run ultra marathons. I've done stuff with her. I've seen her work. She can work for 14 hours straight, cognitive function, completely just as good at

9pm as it was at 7am. It's phenomenal to see. But I'm thinking, if we take a step back for a minute, there are so many reports of people thriving on these animal heavy diets, autoimmune symptoms going, joint pain going. We can either put our head in the sand as a profession and go, no, you've got to do this. You've got to eat more fiber or go, wait a minute, what's going on here? Why are people not following the dietary advice and are thriving? And she's also done all her blood tests, her triglycerides, HDL ratio is fantastic, her HbA1c is amazing. What's your perspective, Tommy? So I completely, you know, on the gut front, and again, I know people who are much smarter, I know much more about this than I do.

So I've learned a lot from them. One of them is Dr. Lucy Mailing, who I wrote this paper with. And I think the gut has really been this thing where the more we know, the more we realize we don't know. And again, the paper we wrote tried to come at this from a first principles idea, which is that, so if we think about the wide variety of environments and diets that humans thrived in and thrived on, how common is it,

how common would it have been for you to have 30 different plant foods in your diet in a week right you're in greece two things are in season tomatoes and aubergines you talked about that right what are the other 28 that you're supposed to find in the environment like it's just not something that our guts ever you know are used quote unquote used to seeing that doesn't mean it's bad right i'm not saying that it's bad. I'm just saying, like, what are the things that, you know, our guts have helped us through in the past? And if you think about it that way, then you have to think about scenarios when, like,

there were no plants, right? So, you know, we've come at it from this idea that, for the gut, plants are essential, fiber is essential. And that's pretty much because in large population studies, we've told people that that's the case. So people who are more health conscious do that, but they also don't smoke and they sleep more and they exercise more, right?

The healthy user bias. And if we think about our guts and the rest of the body is the same but in a healthy individual it's it's adaptable to many different types of fuel right um is it blood glucose or is it fat or is it ketones right these these different um sources of energy that you can use that you need to run your heart or your muscles or your brain your gut is the same and the traditional story is that you need fiber that your gut bugs turn to something we call short-chain fatty acids like butyrate that provides the fuel for your enterocytes the cells in your gut but what you see quite clearly

is that your gut can use a wide range of fuels so yes yes, it can use those. If you eat predominantly plant foods, you'll make short-chain fatty acids like butyrate. That will be the source of fuel. But if you eat more protein, then you'll make what we call iso-short-chain fatty acids. And those essentially have the same function. So you can support your gut health just fine with the metabolites from meat rather than plants. The gut cells will still use it. You can also use A-cell carnotines, which are metabolites from meat rather than plants. The gut cells will still use it. You can also use A-cell carnitines, which are metabolites of fats. Or if you're on a ketogenic diet,

it doesn't come from inside the gut like those other things do from the gut bugs. It can come from the blood. So you can take the cells in the gut can take ketones from the blood. If you're fasting or fasted because there's no food available, right? If there's no food available right if there's no food available your gut still has to be able to survive it can't just like give up and stop

working right because as soon as you get food it needs to function so then if you're for whatever reason don't have access to food your body makes a bunch of ketone bodies and the gut can use those for energy as well so the gut is incredibly metabolically flexible based on the systemic health of the body and physiology of the body so what i think we've seen in a lot of studies around the gut is that something that affects systemic physiology affects the gut and then that affects the types of microbes that get selected for within the gut. Let's just back up. Systemic physiology, how would you say that in layman's terms?

Yeah, so basically your general health. So you do something that's affecting your general overall health. Yes. That's then affecting the health of your gut. Yes. And then you're measuring bugs in there, and we're drawing conclusions from that. Exactly. And it goes in both ways. So we know that the bugs in your gut can affect your body, but it really seems like

what's happening in your body elsewhere, and that can happen with changes in sleep or diet or physical activity, right? So when you exercise, that affects your general health it affects what happens in your heart and your blood vessels and your muscles they you know secrete a bunch of um chemicals and hormones and things like that that can that affects your health it also affects your gut and then what happens is your gut is affected by that right just by your health changing that then changes the kind of bugs that survive in that gut. So you'll see things change within the gut, right? You'll see different bugs, but it's because of what's happening elsewhere in the body. So I think we've ascribed too much

to the bugs that we measure. And it's also the bugs we can measure. There's a whole bunch of stuff that we're just not able to measure and this has been another problem with um studying the gut microbiome is that historically we've used um a cheaper measure called um looking at something called 16s rna um and when i've talked about this um previously the level of information it gives you is it's like if you think about the lineage of dogs right they're in animals and then canines and then the the sort of the house dog the dog that we have dogs that we have at home so a 16s rna can tell you this is a dog rather than a cat but it can't tell you whether it's a french bulldog or a doberman right which are vastly different dogs and it's the same thing with gut bugs so it might tell you whether it's a French bulldog or a Doberman, right? Which are vastly different dogs.

And it's the same thing with gut bugs. So it might tell you, yes, I think I have an idea what this bug is. But it tells you nothing about its specific functions. And a lot more about what's happening in the gut is based on the function of the bug rather than what the bug is. And so vastly different bugs can have the same function. But you might just focus on one that has a specific function and think we need this, when actually something else entirely could take that function.

So the information that we have is incomplete. I think we've ascribed too much to its activity. It doesn't mean it's not important. I think it's very important. No, for sure. But I think we've given it too much credit and and taken away what's maybe happening elsewhere in the body and also maybe it's not even giving it too much credit but it could also be you know we're overly focusing on

lifestyle change influencing the gut microbiome influencing influencing our overall health. Maybe it's just the lifestyle change is influencing our overall health, as you say, which is then influencing the gut microbiome. Exactly. And this is one of the key things I think I've evolved my view on over the past few years, is this maxim that we need fibre for optimal health? I don't know the answer to that. I'm very open minded and I can't make that work in my head cognitively and also see many many people thriving literally thriving in every way that i can see on low fiber diets yeah i think it doesn't add up like we've got to do better like that's that's you know what i mean yeah and and again um i think when we when we've looked at some,

I'm not going to say that fiber isn't important because I think in the setting of the modern mixed diet where most foods are ultra processed and we think about the things that we talked about earlier that may be able to help support gut function, you're probably not getting any of those. And in that setting, fiber may be able to help support gut function. You're probably not getting any of those. And in that setting, fiber may be beneficial. It's also fiber in the diet

when we ask people about their diet. It's like a marker of a bunch of other things. Usually if you're eating more fiber, you're eating higher quality foods and fiber may affect things like satiety, right? So if you're eating more fiber, then maybe you eat total fewer calories in an environment

that encourages us to eat more calories than we need so there are these signals that maybe it's beneficial but that doesn't mean that it's essential yeah and just to just to clarify my own view i'm also not saying fiber is not important there is plenty of research which is suggesting that more fiber is associated with better health outcomes. I've written about this before, right? So I'm just, I think we always need to remain open-minded and go, just because we believe this to be true, just because everyone said it was true, maybe it's a partial truth. Maybe it's true for a lot of people. And also the other thing I think with diet, Tommy, is that when we look at these ancestral populations, these hunter-gatherer tribes, and we look at what they're eating, and the Hadza tribe in Tanzania are reported to

eat a ton of fiber, maybe 100, 150 grams a day. I've seen in some reports compared to an urban population, a Western population that may be struggling to get 15, 20, 25 grams a day, right? So I get that on the face of it, it seems like a huge difference and, hey, we want their health outcomes, so let's do that. Let's increase the fiber. But it also depends, doesn't it, that diet on top of what? Yeah. So if you've grown up there with low stress, eating naturally in sync with the seasons, without the urban Western societal pressures that affect all aspects of our physiology, well, maybe that diet works really well. But maybe in the world in which we live, you live in America now, I live in the UK,

but so many people have got poor metabolic health already. They've already got suboptimal health. So maybe they need a corrective diet. Do you know what I mean? It's kind of like, and I sort of hypothesized in my first book why a low-carb diet seems to work so well for so many people in the Western environment might be because we're overly stressed, we're underslept, we're undermoved, we've had too many calories at the wrong times. The calories, we are insulin resistant. And therefore, maybe in that setting a there's a kind of unique role for it yeah i don't know i mean i'm not saying i've got the answers or i don't think you're saying you've got the answers either but it's worthy of discussion yeah um in my mind uh there's this

you know every every everything that we use to describe human health everything we use in biology is some kind of model, right? And because we can't, we're unable to completely explain everything, right? It's not physics. And even in physics, they can't do that. But there's this famous, George Box is a statistician, has this famous quote, which is called, which says, all models are wrong, but some models are useful. And I think that's really, and I think that's really important to think about

because everything we're talking about here is some kind of model to describe human health. And if your model doesn't allow for the individual that is doing amazingly well eating nothing but beef then your model is wrong right then it's more wrong than any kind of model you can build that that that encompasses that so i always think like the outliers are important because they force you to change the parameters of your model and if you don't i think that's incredibly unscientific so yes you can say that's interesting i want to learn more about that but at some point you then have to try

and incorporate it into whatever model it is that you're building that says you know well why is it that we've seen you know if humans can thrive in a scenario where they're not eating any fiber then that has to be incorporated into the model somehow yeah i love that i love that muscles right we've we've drawn an analogy you've drawn an analogy early on about muscle health to be incorporated into the model somehow. Yeah, I love that. I love that. Muscles, right? We've drawn an analogy, you've drawn an analogy earlier on about muscle health and brain health. And I'm really interested as to practically, what advice would you give to people who want to optimize their brain health in terms of, yes, physical activity, but I guess specifically I'm interested in muscle. I know you lecture on this, you're going to give

a talk, I think, this weekend on muscle mass and longevity in the UK, which you'll hear. We had Dr. Gabrielle Lyon on recently. She was talking about protein intake, the importance of resistance training. I would love your perspective on these things. So I obviously haven't heard your interview with Dr. Gabrielle, but I imagine that I will have agreed with pretty much everything she said. So you can hear what I say, because in general, I think she's fabulous and she she focuses on really important

things which is muscle tissue and protein intake um and the i mean there are multiple reasons why muscles are important there are biggest glucose sinks so you talk about blood sugar you talk about you know that being important for diabetes risk but also cardiovascular disease risk dementia risk 75 of your blood sugar is taken up into your muscles and the more muscle you have and the more you move it the more glucose blood sugar that they take up so if you're trying to regulate your blood sugar which is relevant to the vast majority of of adults because they probably you know again the average individual at least has pre-diabetes, average adult in the US and the UK, and similar studies have been shown that in Europe. That's pretty alarming.

Yeah. And so I think the projected number in the US is 60% have at least pre-diabetes, or obviously if you progress then that includes pre-diabetes and frank type 2 diabetes, 60% of US adults. Currently? Currently. And do you know what that figure is in the uk um i believe it's 40 or 50 yeah so muscles are your most important glucose sink if you want if you want to regulate your blood sugar you need to create somewhere for that blood sugar to go right um and muscles are the thing at 75 of blood sugar to go, right? And muscles are the thing. 75% of blood sugar goes up into your muscles. So the more muscle you have,

the easier it is to regulate your blood sugar. Absolutely. And the more you move it. So both are important, right? So the total mass and then how much movement, the amount that you move it. And there are several studies that have shown that. But you can, again, in type 2 diabetics,

you can put on continuous blood sugar monitors or look at their blood sugar, and the more they move, the better their blood sugar is controlled. And if you have more muscle and you move it more, you can control that even better. So that's one reason why muscle is important. It's also, um, it's a, it's an organ. It secretes factors and hormones and things that we're still learning about, right?

Um, every month there's a, another paper in a fancy journal that says, we just learned this thing that happens when you exercise and it makes this molecule. And then we inject that molecule into mice and they live longer. That speaks to what you just said about the gut, right? How long have we been studying muscles compared to how long have we been studying the gut? Years, decades on muscles, and we're still learning new stuff that we're like, oh, we didn't realise. Yeah. So, it's kind of naive on the gut, isn't it? To think after 10 years of study, we kind of know all this stuff.

Yeah, exactly. And so, one of the reasons why I like to use exercise as an example is because Exactly. And so one of the reasons why I like to use exercise as an example is because everybody, right, diet we can argue about, some other things we can argue about. Nobody argues about physical activity, right? Yeah. Everybody recommends it. Every health body, every governmental organization, every non-governmental organization says you should move more, right? Physical activity is good for your health. But we don't know how it works yet. I mean, lots of things but we don't know all the things that happens when it happens when you exercise and so what you know it's um when you when you exercise you release a whole bunch of factors that you know directly support the brain things like brain derived neurotrophic factor you secrete things that decrease systemic inflammation um a whole wide range of things so it's this it's a secretory organ of course you know just like um just like the the pancreas or the thyroid um but when you move it um and then sort of more practically as you get older we we know that you lose muscle mass as you age and it particularly

starts to decline from about 60 muscle muscle mass so it starts slowly in your 30s and then it really accelerates when you hit about 60 on average but strength declines pretty much continuously from your 30s so you lose strength more than you're more more quickly than you lose muscle tissue and strength is really the thing like functional um functional capacity of muscle is is really important it's like saying you don't want a bigger brain you want a brain that works better right that's that the function is the important thing and strength is a really important predictor of mortality and cognitive decline and there are simple things like if you have enough muscle mass and enough strength then you're not going to fall over you know and break a hip and right if you have enough muscle mass and enough strength, then you're not going to fall over and break a hip.

And if you get into your 70s or 80s, you fall and break a hip, you have a very high chance of dying within the next, well, even days, then also weeks and months afterwards. So your muscle tissue supports pretty much all these important, it supports every other organ in the body.

And what's interesting to me about exercise, particularly when you think about longevity and aging, there was a, about 10 years ago, there was a paper that came out called The Hallmarks of Aging, which are all these things that you can measure biochemically in cells that happen as the body or the cell ages. that happen as the body or the cell ages. Physical activity and exercise is the only thing that reverses all of those components, right? It's the only thing that can actively anti-age you in everything that happens as you age. So it basically affects everything.

And then I know it's important to give practical advice right how how well what's how much is enough and um you know whenever i talk about muscles i have to you know i have a philosophical conflict which is like i really like lifting weights right so everybody you know the first thing that happens when i talk about muscle mass is people like well i don't want to look like don't want to look like you. And like, that's fine. That's great. You don't have to. And you basically just have to be

in the top 50% of the population, right? So if you go out and you find 10 people like you, if you're in the top half in terms of the amount of muscle mass, then you're good. That's enough. That's the challenge to the listeners. Find 10 people who are like you and have a press up competition. That's enough. So that's the challenge to the listeners. That's the challenge. Find 10 people who are like you

and have a press-up competition. Yeah, exactly. And if you're in the top half in terms of the number of press-ups you can do, then you're fine. You don't have to do that. So what does it take to achieve that kind of, something like that?

And it's really not very much. If you've never done any kind of resistance training, and resistance training, I mean, it could just be body weight stuff. Some of the things from your books, like your kitchen workout, you can use bands. Yes, you can use weights and go to the gym, but you don't need to.

This morning, I watched a talk by Professor Seymour Gray, who was talking about the healthiest thing to do with bags of sugar is to use them as weights. I was like, great. Yeah, so you could use bags of sugar. You could use cans of beans. That provides resistance. And if you do two to three sets per muscle group, right? So maybe you have to do bicep curls and squats and a press to like cover all your muscle groups. Two to three sets per week is probably enough. Two to three sets per week?

Per week. So the minimum effective dose to increase strength is somewhere between two and four sets per muscle group per week. And when you say sets, is that 10 bicep curls? Is that five? Is that 15? How do we define a set? So that's a great question. And the, again, what's really great is the answer is it doesn't matter as long as you go to something approaching what we call voluntary muscular failure, which is basically, this is really hard. i can't do anymore right so if you pick if if whatever you're doing you can do five and you're like i can't do six then that's enough but if whatever you're doing you can do 30 but you can't do 31 then that's enough so you just have to get to a point where it gets hard enough that you say i probably can't do anymore um and

you don't need to like really push it and like get to the point where you're like, you know, yeah, your form looks terrible because you're sort of like trying to muscle this thing up. You don't need to do that. It's the same principle as doing something new, isn't it? You're just saying maybe 20 to 30 minutes on something that you find challenging,

but then it's probably enough after 20 minutes or so. It's a similar kind of principle with the muscle. Yeah, exactly. And so 20 minutes, two or three times a week. And even if it's just one set each time, where in whatever you're doing, so say you're doing some squats, and if you can't do squats,

then you could just do like getting up and down from a chair, right? If that's the limit. And if you get up and down from a chair 15 times and you're like, oh, I probably couldn't do a 16th, then that's great that you've done something you need to do. Yeah, I think the important message there is for people, because people tend to get hung up on numbers a lot of the time. Is it 10? Is it 15? Is it five?

It's like, no, it's voluntary muscular failure. So, and that's going to change as you get stronger, right? So maybe it's, you can do only two press-ups now, but as you get stronger, it'll be, you can do only two press-ups now, but as you get stronger, it'll be five is what you need to do. And as you get stronger, it's going to be 10. Yeah. So that's the minimum effective dose. Yeah.

Okay. So the premise is we're trying to maintain our brain health as we get older. Above the age of 30, we start to lose muscle mass. You're making the case that lean muscle mass is very important for our cognitive health and many other aspects of our health. So you're saying the minimum effective dose

is two to three sets on most muscle groups a week. So that's going to do something that you're going to get benefit from that. You've given us the minimum effective dose, but presumably more up to a point i guess can be better yes and so what i think is the bat that like the best balance of like the amount of response you get versus what's practical for most people is probably something more like eight to 12 sets per muscle group per week split over two to three sessions. And so it's very common in the exercise literature to see three times per week, three sets per muscle group.

And then, you know, they usually do like something like 8 to 12 reps and and uh change the weight to get it so that by you know 10 or 11 you're at that point of failure like whatever that is for you yeah so that's and that's very common and so there was um they've done studies where they've compared individuals in their 70s versus individuals in their 20s and with that kind of training protocol so three times a week three sets per muscle group maybe so maybe six to eight different exercises each time even individuals in their 70s you know gaining significant muscle mass significant strength right so again it's not the thing you can't do it right the body still responds it still adapts once you've achieved whatever level you

want to achieve you need much less to maintain it, right? You can maintain it with those levels we were talking about before, two or three times per week, whatever you've built up. So that's important too, right? Maybe you get to a certain point and you're like, well, I only just want to maintain my strength. You need much less to maintain that you need to actively build. So that's important too. There was a very nice study called the SMART and two um there was a very nice study uh called the smart the smart trial where they did gave people either resistance training or cognitive training or both and they looked at sort of function and and um and things uh like structure of the brain they were looking particularly at the brain and these again individuals in their 70s and the resistance training protocol which

significantly improved function and structure in some areas of the brain because we were talking about the brain was just that it was three times a week uh three sets of six different machines in the gym so you could go to your local you know local gym you just do like some kind of row some kind of press a leg press right five or six different machines three times a week three sets of eight to 12 for each. And then that showed significant benefits in the brain. Each session was close to half an hour. So it's 90 minutes a week.

Very doable. Yeah. And to really tie in what we were talking about before, Tommy, about access and making health advice relevant to everyone uh maybe people who don't have much disposable income yeah gyms can be expensive oh yeah right this doesn't have to be a gym you mentioned bags of sugar they can be used as weights tins of beans you know many of us have got dumbbells kicking around you know in the first lockdown in the UK back in 2020 you could not buy dumbbells or kettlebells anywhere I think after a few weeks

literally everyone had sold out yeah so based upon that this is not science but based on that there are many people who have got dumbbells or kettlebells kicking around, sitting at home, maybe in a box, maybe in a cupboard, maybe in the garage under some dust. It's not costing any money if you've already bought it. Huge, huge benefits for your current health, your metabolic health, your brain health. I mean, I know we know this stuff, health, your brain health. I mean, I know we know this stuff, but when you say it out loud, sometimes you go, guys, you got it. You just got to do it. You can't just hear the podcast and go, oh yeah, I know how important muscle mass is. You've got to actually go and do it. But what you're saying is it's not actually that much. I think that one of the most important messages that I like to give around exercise is that literally anything is beneficial.

It's linear. Anything more than what you're doing now will have significant benefits for your health. And what we often think, and we may have talked about this in the last podcast, was that if you're going to go running, it has to be an hour and it has to be hard for it to be doing. You're just like, what's the point in going running if I don't have an hour or if I don't get really out of breath? And that's not true, right? It could be 20 minutes and it could be a brisk walk. And we know that has significant health benefits. And resistance training is the same.

People think that, you know, what's the point in doing it? Because, you know, it's only a four kilo kettlebell. Like surely that can't make much difference. It does. It makes a huge difference. Uh, so it doesn't take much. Um, and you can do it with, so like, um, I'm traveling for 10 days right now. I won't have access to a gym. I brought two things, a set of resistance bands and blood flow restriction cuffs, which you can talk about more if you want, but basically it makes any exercise that you do much harder with your body weight and you sort of augment the response to it um and it weighs i don't know maybe a kilo could put it in the bottom of my backpack and i will get great workouts and oh and it maybe costs 20 quid in total the things that i have in my bag um and that would be enough, right? If I was somebody

who was just focused on resistance training for health, I could have those two things and do everything that I needed to do to get almost all the benefit. Yeah. You know, when I travel, do you know what I take with me? What? Skipping rope. Yeah, great. Now, I'm super tall, right? So I had to get an extra long skipping rope maybe about seven years ago so I got it with my life it's quite hard to get you know people don't realize when you're as tall as a giraffe it ain't easy to get stuff but I took that holiday with me this summer pretty much done more skipping this summer than I've done in my life it's phenomenal oh yeah uh you know this whole thing about it not being accessible, that's accessible.

What you just said is accessible. These restrictors, these blood cuff, what were they called again? Blood flow restriction. Blood flow restriction. Yeah. I do want to talk about them, but I think we're going to have to save that for conversation number three,

which I hope we can have because I so enjoy talking to you. We've tantalized people with blood tests throughout this conversation. So some of these blood tests that are, you know, pretty well available for people. What blood tests do you recommend? What do you think are the most important ones? Are they only going to do a few? And I wonder if you're open to sharing what you think are the most important ones are they're only going to do a few and i wonder if you're open to sharing what you think the optimum parameters are what people should be aiming for i've done like i said earlier a bunch of work in blood tests and i've also done a bunch of gut testing and fancy urine testing and all these all these kinds of things on yourself on myself

others on you know clients and athletes that i've worked with and again again again i just like come back to some of the basics that i think can can be really important the average adult in the uk probably has at least one or two of the components of metabolic syndrome and so just say we what metabolic syndrome is? Yeah, so we talk about metabolic health, we talk about insulin resistance, these things related to diabetes and cardiovascular disease risk and dementia risk.

And one of the easiest ways to explain metabolic health to me is the absence of metabolic syndrome, which is this um syndrome that's um increasing in prevalence and it basically the the more factors you have increased your risk of cardio acid disease certain cancers and it's basically this expression of systemic insulin resistance so your body's inability to handle energy properly that's probably the the easiest way to do it and or to to talk about it And the way we measure that is with the blood sugar test. That's one of the ways we measure insulin resistance.

Either just a fasting blood sugar in the morning or on HbA1c, which is more of like a, you know, a picture of your blood sugar over the last couple of months. And the components of metabolic syndrome are an increased waist circumference. They are low HDL cholesterol. It's different for men or women. High triglycerides, high blood sugar, and then high blood pressure. So if you were to avoid having any of those things,

you're already in such great shape. And that's a really low bar to hit. And those are things that you can get from your GP. And you can easily track over time. And they're very cheap. So that's absolutely where I where i'd start okay so let's go through some of them yeah uh fasting glucose so fasting glucose um the the criteria for high fasting glucose in metabolic syndrome is the the presence of pre-diabetes so um there are two ways that you can diagnose that one is either a fasting blood

sugar over 100 milligrams of deciliter, which is 5.6-ish millimoles per liter, or an HbA1c above 5.7%. I can't remember what that is in millimoles per mole. But you know what's really interesting is that in the US, the pre-diabetic threshold is an A1c of 5.7. In the UK, it's 6. Oh, interesting. So we have actually a different arbitrary number when we call it pre-diabetes. Yeah, and it is arbitrary. We've had to pick a cut-off point, but of course these things are on a continuum, like everything that we've talked about today.

So if we go on A1c and fasting glucose for a minute, because there's normal, there's okay, and then there's optimal, right? So, of course, not being in the abnormal range is a good start, but many people, I would guess, many people listening to this show are actually going, yeah, okay, but what should I be really aiming for? So with an HbA1c, again, in kind of old money, So with an HbA1c, again in kind of old money, you know, 6.5 is a diagnosis of type 2 diabetes, 6 in the UK or 5.7 in the US is a diagnosis of pre-diabetes.

Where would you ideally like to see people's A1c's? Can we say that yet? So there are a number of very large population studies that have looked at blood sugar levels, both fasting blood sugar and HbA1c, and then looked at things like mortality, which is like a hard endpoint. It's easy to know, like, is this person dead or not? And you can then say, well, where is the lowest risk of death on, you know, on the glucose scale. And it seems to be somewhere around maybe 4.5 to just over 5 millimoles of fasting blood sugar. And maybe something similar for HbA1c, like 5 to maybe 5.5 is where the lowest risk of mortality is at the population level. That's probably because having much lower blood sugar is usually associated with other problems

like alcoholics have lower blood sugar. And it's not the low blood sugar that's the problem, it's the fact that they're alcoholics. So you're looking after someone and they've got an A1c, an HbA1c, which everyone listening to this show at the moment probably has access to for either free or very low cost. So it's something practical that people can actually measure, look at, and then compare it to what we're saying. If someone's got it between then 5 and 5.5, let's say it's 5.5, so only 0.2 away from 5.7.

Are you happy with that or do you think lower might be better or does it depend on the context of everything it absolutely depends on the context of everything else if your uh hpa1c is 5.5 and you you know you have um i think waist circumference is tricky um i like waist to height ratio. Yeah, me too. So say you have an HBMC of 5.5, but your waist to height ratio is close to or below 0.5, which I think is a good cutoff.

And again, above that is associated with a higher risk of mortality. And you have good blood pressure and everything else is good. No, I'm not going to focus on decreasing it further. What's tricky about HbA1c is that an HbA1c is supposed to be a picture of your average blood sugar, but you and I could have the same HbA1c and have very different blood sugar over time because there are a number of things that affect red blood cells, which are then part of that HbA1c measurement. So say you're at the upper end, you're near the threshold, then I would look at fasting blood sugar. You know, if that looks good, you know,

you know, you can if you want to dig even deeper, you can look at like, how hard how hard is your blood sugar spike after meals, right? Because if it goes really high, and it takes a long time to come down, and you've got a sort of a borderline HbA1c, maybe that's a picture of you're maybe on the way to having some blood sugar. I guess that's harder for people to measure unless they're wearing a continuous glucose monitor. Because, you know, it's certainly in the UK not that accessible to be able to do something like that. But I agree. And I guess a wider point, Tommy, which I think it's worth just pausing on here is looking at just one of these tests, sure, can be helpful. But it's best to look at them in combination altogether. You know, what is your blood pressure? What's your triglycerides? What's your A1C? You know,

to build up a picture. Would you agree with that? Oh, absolutely. And I think one thing that particularly individuals who are very health focused, is they become too focused on optimizing each individual thing. When in reality, we have no evidence that that's that important um which is why i think taking the context of like one thing being maybe close to a cutoff that somebody said wasn't that great in the you know if everything else looks really good and you feel good i mean i think at that point you should just you should just stop worrying about it right take it into the context of everything else don't like hyper focus on every individual number and try and maximize it blood sugar in the context of brain health cognitive health right just to sort

of close that loop a little bit um we're talking about fasting sugar we're talking about hba1c things that people can do they can see what you know if it needs improvement if they need to make some changes but what is the relationship between high blood sugar uh raised blood sugar uh swinging high and low blood sugars basically what is the relationship between poor metabolic health in in many ways and brain health some people have called alzheimer's disease like the late onset alzheimer's disease the age-related dementia we're talking about type 3 diabetes some people may have heard that and that's because the brain becomes insulin resistant you see that the brain is able to take up less glucose and with that you're delivering less of one of those things that we talked about, right? Glucose as an energy source is one of the things that your brain needs,

like we talked about earlier. And there are a number of reasons why that may happen. But when we see peripherally, when we measure our blood sugar, there was a nice study done, I believe it was done in the UK, the Aging in England study or something like that. And they looked at individuals that had normal blood sugar, pre-diabetes or type 2 diabetes. And within those categories, as you went up each category, the cognitive decline was faster and brain atrophy was faster. So the higher your blood sugar that's associated with

faster cognitive decline within those within those categories either by normal pre-diabetes or types of diabetes and it seems that this is like systemic reflection of your health that is directly affecting the brain and we see similar things with blood sugar swings so there there's a nice study done in japan and actually a lot of a lot of studies looking at blood sugar swings so there there was a nice study done in japan and actually a lot of a lot of studies looking at blood sugar variability have been done in japan where they look at something called the mage the mean amplitude of glycemic excursions which basically says how big are your spikes in blood sugar and the bigger your the bigger your spikes in blood sugar after a meal a core is correlated with those things we talked about pre-diabetes type 2 diabetes so the bigger your spikes in blood sugar after a meal is correlated with those things we talked about,

pre-diabetes, type 2 diabetes. So the bigger the spike, the more likely you are to have pre-diabetes or type 2 diabetes or get those conditions. But related to the brain specifically, this was a trial of a drug to treat type 2 diabetes. And at the beginning of the trial, they looked at MAGE, like how big are an individual's blood sugar spikes. And of all the trial they looked at mage like how how big are this an individual's

blood sugar spikes and of all the things they measured blood sugar spikes were the best predictors of cognitive function i.e the bigger the spikes the worse the cognitive function but what's really nice and really important is that this effect was reversible. So the greater, the more that somebody's spikes improved over the two-year trial, the more their cognitive function improved. So again, it's one of those things where, you know, somebody could say, well, I have pre-diabetes, it's going to affect my brain, there's nothing I can do about it. That's not true. Like there are studies that show this is reversible. If you can improve your blood sugar control, you can improve your cognitive function. Yeah mean that's super powerful tommy and

again we're trying to close down this conversation there's there's new avenues being opened up all the time so we're gonna have to we're gonna have to commit on air to a part three at some point uh just to finish off the podcast is called Better Live More. When we feel better in ourselves, we get more out of our lives. In the context of brain health, right at the end of this conversation, for people who want to optimize their brain health, reduce how much it declines as they get older, have you got any final words for them? Yeah, it all boils down to everything we've talked about

in relation to the brain and the body. The function depends on the demands you put on it. And I mean that in a good way. So do things that are difficult and then give yourself a period to rest and recover. That's it, really. It's fairly simple. And anything that you enjoy, you know, if you can do it in a social situation, maybe that's even better, right?

There are benefits from social interaction. So a few times a week, spend 20 minutes doing something that's difficult, learning a new skill. And that's probably by far the biggest change that you can make to really change the trajectory of your long-term brain health. Dr. Swami Wood, thank you very much.

Thank you. Really hope you enjoyed that conversation. As always, do think about one thing that you can take away and start applying into your own life. Now, before you go, just wanted to let you know about Friday Five. It's my free weekly email containing five simple ideas to improve your health and happiness. In that email, I share exclusive insights that I do not share anywhere else, including health advice,

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