Caring for your heart may prevent dementia, with Dr. William Li

We’re all aware of dementia. It affects more than 55 million people worldwide, and this figure is expected to double every 20 years.

But did you know that there may be ways to prevent it? 

In today’s episode, Dr. William Li, a renowned expert in cardiovascular and metabolic health, reveals why caring for your heart isn’t just about longevity — it’s about maintaining sharp, effective brain function as you age. 

He explains how simple strategies involving diet, exercise, and sleep can significantly influence brain health and may prevent dementia.

William’s groundbreaking work has led to new treatments for more than 70 diseases, including cancer, diabetes, blindness, heart disease, and obesity. He’s also a New York Times best-selling author.

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Episode transcripts are available here.

Transcript

[00:00:00] Jonathan Wolf: Welcome to ZOE Science & Nutrition, where world-leading scientists explain how their research can improve your health.

Today, we uncover why heart health plays a powerful role in brain health as you age. One of the biggest threats to brain health is dementia, and about one-third of people over 85 have some form of this condition. 

In its earlier stages, dementia can lead us to be forgetful, whether that's losing our keys or forgetting a loved one's birthday. At a later stage, it can confine us to our homes and ultimately kill us. 

But the good news is that this terrible condition is not inevitable. What if I told you you have more control over it than you think, and that the secret to maintaining a healthy mind could be beating in your chest?

Today's guest, Dr. William Li, is a world-renowned physician, heart health specialist, and New York Times bestselling author. Will helps us unravel the mysteries of the so-called heart-brain axis. In this episode, we learn how you can protect your mind by caring for your heart.

Will, thank you for joining me today. 

[00:01:25] Dr. William Li: Thanks, Jonathan. Always glad to be here. 

[00:01:27] Jonathan Wolf: So you may remember we have a tradition here at ZOE where we always start with a quick-fire round of questions from our listeners with these very strict rules. You can say yes or no, or if you absolutely have to a one-sentence answer, designed to be really hard for sort of professors and scientists.

So you're willing to give it a go. 

[00:01:45] Dr. William Li: Absolutely. 

[00:01:46] Jonathan Wolf: Okay. Is dementia connected to blood vessel damage? 

[00:01:51] Dr. William Li: Yes. 

[00:01:52] Jonathan Wolf: Can I reverse blood vessel damage? 

[00:01:54] Dr. William Li: Yes. 

[00:01:55] Jonathan Wolf: If I have dementia, is it possible to slow down the progression of symptoms? 

[00:02:00] Dr. William Li: Absolutely. Yes. 

[00:02:02] Jonathan Wolf: Does my mental health impact my risk of cardiovascular disease? 

[00:02:06] Dr. William Li: Yes. 

[00:02:07] Jonathan Wolf: Too many yeses, all right, it's pretty good, it's exciting. Can improving my diet help me combat memory loss? 

[00:02:13] Dr. William Li: Yes. 

[00:02:14] Jonathan Wolf: And finally, what's the most surprising thing about the connection between our brain and our heart? 

[00:02:22] Dr. William Li: That's not a yes question. 

[00:02:23] Jonathan Wolf: No. You can give me a sentence. 

[00:02:26] Dr. William Li: I think the gut connects the brain and the heart. That's one of the big surprises.

[00:02:30] Jonathan Wolf: You know, the last conversation we had, which was back in 2022, which was about blood vessels and heart health, is actually one of our biggest-ever episodes, with over 2 million listens. So, I'm very confident that today's episode is going to be really fascinating. And this time around I wanted to talk about something different and that's the connection between our heart health and our brain health, and in particular dementia.

And I was completely surprised to hear that there was a link between my heart and my risk of dementia. And I think that's going to be true for most of our listeners. And it's a topic that actually is very close to my heart because my grandmother had Alzheimer's and so I've seen firsthand how dementia affects not only the person who ends up living with it, but everyone else in the family.

So, I'm really excited because I think today we're going to talk about the way that there are things that you can do to change your risks. I would love to believe that my parents will listen to this and change any aspect of their lifestyle as a result. I'm pretty sure it won't happen, but I'm definitely going to share the episode.

So, can we just start at the beginning? Will, what is dementia and is it the same as Alzheimer's disease? 

[00:03:34] Dr. William Li: You've just asked a huge question because dementia is one word that represents the end result of many different processes, problems that impact our brain. And so it's sort of a final result of different types of disease states that can actually happen to us.

And people tend to underestimate how complicated and how different types of dementia actually exist. So you asked about Alzheimer's disease. Well, you can call it Alzheimer's dementia. It's the type of dementia that we attribute to Alzheimer's disease. And even Alzheimer's itself, we're beginning to realize there's different flavors or different types of Alzheimer's disease, and it's not one size fits all.

So, you know, we've kind of moved from a table of contents on dementia where we have simple chapters of understanding the brain, to really beginning to understand this is a dictionary and there's a lot of different definitions that need to be precisely understood in order for us to be able to better prevent better treat and indeed better reverse the condition.

[00:04:38] Jonathan Wolf: So we're sort of discovering that it’s lot more complex than maybe many of us listening had understood, in terms of it's not just one disease, there's many different ways and underlying explanations for why this happens. 

And if you were going to just sort of summarize, I guess, the symptoms that would distinguish someone with dementia from someone who's just getting older, what are they?

[00:05:03] Dr. William Li: You know, I think all of us inherently can recognize the symptoms of dementia if you say it. So, memory loss, cognitive problems, you know, you can't figure out, what was I about to say? Maybe misplacing your keys, maybe not being able to solve a problem, you know, executive function, decision making.

These are the things that, you know, we associate as people get older and then ultimately have dementia. We say these are the symptoms of dementia. 

Now it can get even more serious. There are, you know, well-known figures like the Bruce Willis of the world who have lost the ability to speak, as aphasia. That's another, you know, process. Our ability to speak is driven by the brain. And so when we actually have a misfire or derailing of those processes that allow our brain to normally function, it can happen through our ability to speak and our ability to think, but also our ability to breathe and our ability to eat, which is fundamental to life itself.

This is one of the reasons why dementia itself makes people feel apprehensive. You know, you sort of lose everything is the impression. But the good news is we're actually beginning to peel back the layers of the onion. And as we do so, yes, things get more complicated, but we're beginning to realize that there may be some solutions for prevention and treatment as well that we didn't appreciate before.

[00:06:23] Jonathan Wolf: I think that's a lovely sort of positive idea within something which, you know, is pretty depressing, and one of these things that I think, you know, many of us sort of fear might be happening in the future. You already mentioned in the quickfire round, that dementia is linked to our blood vessels.

Could you explain? 

[00:06:43] Dr. William Li: Okay, well, I'm an expert in blood vessels. I study blood vessels, and many people don't realize this, but we have 60,000 miles worth of blood vessels packed inside our body, adult body. But 400 miles of those blood vessels are packed inside our skull, around and inside our brain. 

Four hundred miles of blood vessels inside our brain, and these blood vessels actually grow in, it's kind of like a map, like Google maps. And if you kind of look at where are all the highways and byways of the brain, you will also see with the nerves, the nerves of the brain track alongside the blood vessels, blood vessels and nerves course side by side. 

So when our blood vessels are healthy, our brain has a chance to be healthy. When our blood vessels are sick, not a chance that your brain is going to be healthy. And so that's one of the reasons why it's so important and so possible to actually tend to the garden of our blood vessels. Those 400 miles in our brain is so important to take care of. 

[00:07:45] Jonathan Wolf: Four hundred miles. Firstly, that's an awful lot of blood vessel crammed into my little brain. So it's hard to get my head around. 

I can understand, obviously if you didn't have any blood vessels then your brain is obviously in trouble. So that follows. But how is that linked to dementia? 

[00:07:59] Dr. William Li: Okay, let's take it a little bit further back to how our blood vessels help normal, healthy brains, right? Like when we're children or adults, you know, and we're in our prime. What are our blood vessels doing? 

Well, first of all, our blood vessels are the channels, the highways and byways to bring the oxygen that we breathe to every brain cell and also the nutrients that we're eating through our diet. Those blood vessels are bringing those nutrients to our brain cells. So the highways and byways of nutrition, the lifelines of oxygen, like the scuba tanks of our brain.

This is what our circulation actually does. And by the way, that circulation, those highways and byways, have to be very, very smooth and unimpeded. There shouldn't be potholes in the road, there shouldn't be blockages in the road, no boulders should be in the road blocking the blood flow. 

Now, what happens when you have potholes is that you know, you wind up actually dinging your tire, just like when you're on a highway and you have a pothole, it's damaging to actually go down that highway where the road is damaged, blood vessels can be damaged.

And so it's so important for us to maintain the healthy lining or the surface of the blood vessel. And we absolutely need to avoid getting blood clots in our brain. A blood clot in the brain is kind of like a boulder from an avalanche that got set down into the middle of the highway. And so now you got to stop, and now the traffic piles up behind you, and that's exactly what happens in a stroke. 

[00:09:26] Jonathan Wolf: This is your boulder analogy. It's just completely blocked and so no blood can continue to flow through this particular vessel. 

[00:09:32] Dr. William Li: No oxygen, no nutrients. And what's going to happen? The brain's going to suffer, including dying, potentially.

Now, one other issue that can happen with blood vessels is you need to have the structure of the blood vessel to be really, really solid, so it's not leaking. So think about a blood vessel as a tube, like a garden hose, maybe, you know, for your lawn in the summertime, as long as the water is flowing through the tube, you're fine. You can water your lawn. 

But imagine if you actually poked lots of holes in the side of that garden hose and the water sprang out everywhere. When blood leaks out in your brain through your abnormal blood vessels, the blood leaking out can also cause a different kind of stroke. 

And there's one more thing about blood vessels in the brain, which is probably very linked to dementia and let's call it brain health before dementia. That's what we really want to talk about is how do we keep a healthy brain and avoid dementia? There is a grate, a sewer grate, a filter between our brain and the rest of our body. And it's made of blood vessels is called the blood-brain barrier.

It's not really a barrier, it's more of a filter. It actually protects everything above our neck. Meaning our brain, our eyes, all those sensitive structure from everything else in our body. So if we wind up having a raging infection in our body, that filter protects our brain from getting infected.

And similarly, that grate is made out of our blood vessels. So we need good healthy blood vessels to have an intact blood-brain barrier. It's not really a barrier. It's a protective shield, it's a filter, it's a sieve. 

Now, here's the whole thing based on everything we just talked about. Four hundred miles, highways and byways to bring oxygen and nutrients and help to guide nerves along the brain. Filters, protects our brain and our eyes, all dependent on good slick blood flow. No leaking, no bleeding, no boulders, no potholes, no sticking of anything along that blood supply.

This is really the importance of the blood vessels. As long as we actually have good, healthy blood vessels in our brain, we have got brain health. And I'll just repeat something I said earlier. When your blood vessels are healthy, your brain has a chance to be optimal in terms of its health. When your blood vessels are unhealthy, not a chance can you actually have optimal brain health.

[00:11:51] Jonathan Wolf: So you've got to have these really healthy blood vessels if you want the brain to be healthy. And if it's going to start to go wrong with these blood vessels, and I think you gave some obviously sort of catastrophic examples with like a stroke. 

But it sounds like you're going to take us through the idea that it’s not necessarily always like this instantaneous incident like that where, you know, you're healthy one minute and you're having a stroke the next minute. I'm guessing you're saying that things can also deteriorate over time. 

[00:12:17] Dr. William Li: Right. Our blood vessels are carrying us through our everyday lives and decisions, ordinary decisions we make can influence the health of our blood vessels.

How high our blood pressure is, if you've got hypertension, high blood pressure, continuously for years, put you at a higher risk of having blood vessel problems in the brain, including stroke. If you have low blood pressure, Similarly, it could actually interfere with the amount of blood that is going to nourish your brain.

If you've got clogs in your heart, if you've got clogs in your legs, you know, atherosclerosis, narrowing of the blood vessels, that's also happening in the brain. Not enough blood flow to the brain, it's going to affect the performance of your brain. 

[00:12:56] Jonathan Wolf: And Will, is there anything, because I guess, you know, I need good blood vessels, presumably in my little finger as well to make this function. So I guess across my whole body, this is important. 

Is there anything particular about the brain that makes it sort of more vulnerable to the good functioning of this? And I'm sort of curious, you describe this sort of special barrier for my brain that I don't have anywhere else. So what's that about?

It suggests that somehow the brain is different from the rest of our body. 

[00:13:24] Dr. William Li: The brain is the mastermind of health and of life itself, so you can lose an arm, you can lose a leg, you could lose a kidney, no problem. Okay, you can have failure of an organ, no problem. As long as your brain is functioning, you're going to be breathing. You're going to be thinking you're going to be able to, you know, do the fundamental things that we need to just survive. 

And so over time, evolution has made it so that the most important thing that our body protects first and foremost is our brain. It is the number one thing. So, for example, you know, people who wind up being in a bitterly cold area, let's say you get lost in the North Pole, all right? Your whole body shuts down, okay? Except for your brain. Everything gets preserved to the brain. 

[00:14:06] Jonathan Wolf: Got it. And hence, you're sort of set to try and protect this. So help me to understand a bit about then sort of the dementia link through to the heart, because you've talked a bit about blood vessels, but how are these two therefore linked together?

[00:14:23] Dr. William Li: Okay, we just talked about nourishing the brain, maintaining the oxygen status, maintaining the nutrient status, and by the way, once those oxygen nutrients get deposited in your brain, the brain is very metabolically active. Meaning that it chews up a lot of energy because it's, you're thinking, but you know, the thing is that's interesting about the brain and I'm going to connect this to the heart, but I want to make this a very important connection is that when you think your brain is least active, it is super active and that is when you're sleeping.

Most people say when I'm sleeping, I'm not thinking about anything. Maybe I'm dreaming, but it's probably, you know, I used to think this must be a little pocket in the corner of my brain. This, I don't know, imagining something, but not a big deal. I'm not doing a math problem, you know, I'm not doing my taxes.

But here's the thing when we're sleeping. The rest of our body shut off, but our brain is recycling and rebooting itself. It's cleaning itself. And in fact, the same system of blood vessels is collaborating with an entire hidden sewer system in our brain. Alright? So blood vessels are circulation.

There's a whole other system that's related to blood vessels called lymphatic channels. They're lymph channels, right? So you'd have lymph nodes under the arm and around your groin. They're also in the brain. The ones in the brain are like the sewer system of Paris. Now, if you know anything about the sewer system of Paris, you can't see the sewers of Paris from the beautiful stones and the beautiful, you know, Haussmann buildings and the incredible statues that are above ground.

But there's this amazing, torrential, cleaning system underneath the cobblestones of Paris that is continuously at work. Now in our brain, we have a sewer system of Paris of our brain that's closed during the day. Okay. Closed for up for shop. But at night when we're sleeping and especially when we get good quality REM sleep, that's deep sleep, the sewer system opens up and the sewer system drains out all the toxins that build up during the day. 

The blood during the day through those 400 miles brings in the oxygen and nutrients. The brain is churning, supercharging. Okay. And at night when we think it's inactive, it is recycling. It is dumping all the toxins that accumulate during the brain through these lymphatic channels.

[00:16:36] Jonathan Wolf: And so this just to make sure we're going to talk, this lymphatic channels I can think of as like another set of all of these vessels, a bit like the blood vessel, but it's separate, which is for sort of draining out. 

[00:16:49] Dr. William Li: And it's connected to the blood vessels because the drain has to be connected to the spigot, right? The blood vessels are bringing the fluid in and the drain is connected to the spigot. 

[00:16:56] Jonathan Wolf: This is really happening at night in our brain because it can't happen while we're awake.

[00:17:00] Dr. William Li:  It does not work while we're awake and it only happens at night when we have good quality sleep. And by the way, when you don't get good quality sleep, think about that all-nighter you pulled maybe in college or maybe a party or maybe some event in your life where you just couldn't sleep.

Well, what happens the next day? You feel kind of brain-foggy, right? You know why that is? It's because the sewer system didn't drain all the toxins. We are going through the next day with toxins that are built up in her head and the brain hasn't cleaned itself yet. That is really helping us understand, it's a window into dementia.

So, I want to back it up now because I just explained to you as to how I think, and researchers are thinking about the importance of circulation in, drainage out of our brain and protecting it, right? Okay, so how does that connect to the heart? Well, all of these functions of pumping in nutrients, pumping in oxygen, is tied directly to our heart.

Our heart is the pump, it is the pump that takes blood from the well, if you have a well in your house and you want to actually put water in your sink or in your shower, you want to take a shower, you need that water pump to be working. All right, so that's the heart. Lub-dub, lub-dub, every single time your heart contracts, it is jetting up those oxygen molecules and the nutrients to be able to feed your brain.

Weak heart, weak circulation, weak blood flow, weak brain. That's one of the most powerful connections. And so, by the way, when you talk about heart-healthy foods or heart-healthy lifestyle, you know, do your exercise, you know, lower your stress, you're actually thinking about the heart, but you're really talking about the brain.

[00:18:39] Jonathan Wolf: Because by improving the heart, you're directly going to improve sort of the health of your brain.

[00:18:42] Dr. William Li: Directly. And not only is it a physical connection through circulation, flowing blood. But there's also hormones that connect the heart to the brain and the brain to the heart as well. And this is sort of like, you know, we used to think of, Oh, it's the heart is a circulatory organ. Now, we actually realize the heart is also an endocrine organ. It's sending hormones that go up into the brain as well. 

So, you know, when you feel heartbroken, right? It literally means something, like when you feel pained, you know, broken relationship or something that didn't succeed, your brain is hurting and your heart is hurting. This is an example of that hormonal link. 

So heart and brain is connected through lots of different channels. And when we actually want to take care of our mental state, our cognitive state, we have to think about taking care of our cardiac or heart state as well. 

[00:19:33] Jonathan Wolf: And Will, you mentioned about this lymph system that I had never heard of before, has been sort of the drainage out and that that was very important for like clearing out our brain.

How is that linked to the heart health and the blood vessel health that you've been talking about? 

[00:19:50] Dr. William Li: Well, it's really interesting. So, first of all, the lymph channel in the brain has got a special name. It's called the Glymphatic, G- L-Y-M-P-H-, glymphatic, because the G part is related to glia or brain cells. We call them brain cells, glial cells, nerve cells. 

So glymphatic channels are not like any other drainage system, lymph system in the body. It's specialized to the brain. And what happens is that when you actually don't have good drainage overnight, you're not clearing the sink. 

What happens in the kitchen when you've got a clog in your drain, or you've got the stopper in, and you've got dirty dishes in the sink? It drains, it fills up, and all the goo and gunk floats to the surface, and you don't want to put your hands in there. That's brain fog of the sink. But when it, when you don't drain your brain with good quality sleep, that's now in your head. 

Now, I mentioned that the brain sends signals, neurotransmitters, that power the heart. Okay. And power breathing as well. So when you actually have a backup of the kitchen sink, by not getting good sleep, meaning that you're not getting good drainage, you've got toxins building up in your brain. It interferes with the signals that your brain is supposed to send to your heart and your lungs in terms of how you breathe and how your heart beats.

Eventually, if you don't actually have enough good quality sleep and you build up these toxins, I mean, think about these extreme situations where people are not sleeping for days. Okay. Now, look, I trained, as a medical doctor, during the training period, we had to stay up for days at a time. It did not feel good.

We always had brain fog. And, you know, and some people wound up having palpitations, you know, fast heartbeats. Our hearts weren't functioning normally either, and we would take shallow breaths. We weren't taking neat, normal, deep breaths because, as we said earlier, our brain is the engine that controls all the other healthy functions, including our heart.

And so this is why I brought up the whole issue about the glymphatic system. 

[00:21:49] Jonathan Wolf: Because if it's not draining properly, then actually it's going to end up having this sort of negative impact back on your heart. And then that's circling back around into your brain again.

[00:21:57] Dr. William Li: Exactly.

[00:21:58] Jonathan Wolf:  Okay, so you're basically saying these things are very, you know, sort of tightly linked.

I think anyone listening at this point is like, okay, so it's pretty clear I need to make sure that all of these blood vessels are in good shape because otherwise, I'm going to start to have all of these negative effects. 

Maybe, just before we go on to how we can improve them, could you help us understand, I guess, the final jigsaw, which is like, imagine you're seeing this deterioration in the blood flow in your brain. You described maybe the stroke, which is obviously like this one-off effect. But I think we were talking at the beginning more about dementia. 

How does this link through to sort of the symptoms that you were describing at the beginning?  

[00:22:38] Dr. William Li: One of the most common forms of dementia is something that is not often mentioned and not well understood by the general public, it's actually not Alzheimer's disease, okay? It's actually called vascular dementia. Vascular dementia is really just, vascular meaning blood vessels, referring to blood vessels, it's just narrowing of those blood vessels, the 400 miles, getting narrower and narrower, and not feeding the brain adequately.

So if you cut down your blood flow to your brain by 5% cut it down by 1%, you'll probably not be feeling quite as sharp as you were. You cut it down by 5%. You're going to start definitely losing cognitive ability. You cut it down by 10 or 15%, which is what we're seeing in vascular dementia. Once you get it beyond a certain level where you're just not getting a blood flow.

And by the way, this isn't only the big fat arteries that your heart pumps through your neck to your brain. We're talking about the capillaries. We're talking about the paper-, the hair-like thinness of the capillaries, the smallest blood vessels that are percolating in every tissue in your brain. When those get narrowed, guess what? You're not getting enough blood flow. 

So this whole idea of flow, flow in, flow out, normal flow, abnormal flow, vascular dementia is really the most common form of dementia. And actually it it leads to those symptoms. Compromised executive function, memory problems, difficulty in remembering what you just said, where you left your keys.

[00:24:07] Jonathan Wolf: All of this starts with just, you're talking about quite a small reduction in your blood flow, right? You're not saying it like halved or anything like that. You're saying that even like a 10%, so that's like a pretty small, you know, if I was driving, it's like going from 60 miles an hour to 54. Like, these are very small differences.

You're saying this can actually lead to this form of dementia. 

[00:24:26] Dr. William Li: That's right. And that's because our brain is so reliant on having the fuel in order to be able to function. The oxygen, the nutrients, we need that fuel. It also needs sugar. Your brain is one of the most sugar-consuming, fuel-consuming functions.

So, you know, we hear all this stuff in the public now about, you know, glucose spikes, and watch out how much sugar you eat, and you shouldn't be… sugar is dangerous. Look, our brain, the most important organ in our body, relies on sugar. It is going to protect itself, it's going to use that fuel, it's going to generate its own fuel if it needs to in order to be able to actually function.

And so vascular dementia is the most common cause of dementia. And by the way, vascular dementia is the brain part of narrowing of the arteries that can happen elsewhere in your body, including your heart. 

[00:25:13] Jonathan Wolf: And can I make sure I just heard that you said that vascular dementia is the most common type of dementia you can get.

[00:25:18] Dr. William Li: That's correct. 

[00:25:19] Jonathan Wolf: I don't think I've ever heard of it, but actually that is now, when you're describing at the beginning about the dictionary of understanding the different sorts of dimension, this is actually the most common sort of cause that we now understand. 

[00:25:29] Dr. William Li: It's a root cause of compromised brain function as we get older. And the reason is because, think about it, narrowing of the blood vessels happens everywhere in the body. Right. And we know that cardiovascular disease is the number one killer around the world. And what is it caused by? Narrowing of the blood vessels.

We used to think about it only in terms of the narrowing of the blood vessels and the heart or the limbs. And we should realize the same thing is happening in the brain as well. And so again, heart disease and brain disease, I mean, heart disease is a brain disease, which is the whole point of why you're asking this question. Heart and brain go hand in hand. 

[00:26:05] Jonathan Wolf: Brilliant. And I think I should clarify, because you were talking quite rightly about how we will die if there isn't any blood sugar in our blood, and which I know, from now being at ZOE for quite a long time, is often called blood glucose.

Just to clarify, you're not saying that people need to eat sugar in order to have sugar in their blood. You're saying that it is completely normal to have blood sugar and that actually your body is both able to create it as well as being able to take it from all sorts of, you know, complex foods that we eat, nt, not just sugar. 

[00:26:35] Dr. William Li: Here's the whole thing. Our brain and our whole body is engineered to be able to function, blood glucose is normal, healthy in the bloodstream and at normal levels. And what we don't want is extra added sugar, which is what we see in these ultra-processed foods and in sodas and things that are that we know aren't good for us.

So we don't want to be piling it on. We want to optimize and work it in sort of that perfect, you know, like our bodies a race car. You want to actually just make sure it's running on the perfect amount of fuel, not too much and not too little. 

[00:27:08] Jonathan Wolf: Let's talk now because I think you've put together a slightly scary story about how even a very small sort of reduction in the way that my blood vessels work can, you know, lead to dementia.

What is going to cause that blood flow to start to get worse and these blood vessels to cease to be these sort of beautiful highways that you're describing? 

[00:27:30] Dr. William Li: Well, you know, I'm going to turn my answer inside out to your question, which is how does our body normally prevent this from actually happening?

Because that's the amazing thing. Like why don't we get dementia when we're younger? So you know, as a scientist, I like to ask the questions that haven't, don't have the answers yet. Right? 

So the thing that's interesting is we're beginning to figure out that when we are young and when we are in our prime, our body's health defenses, these are systems in our body that are hardwired, protect our brain. And so, our bodies are normally geared, when we're healthy, to be able to do everything possible to protect our brain. 

Our body protects our blood vessels, we got good circulation, we can grow more when we need them. You don't want to actually have them bleeding or leaking or having any kinds of problems. They are absolutely slippery smooth. We actually are able to control inflammation. 

And so, you know, we talked about if you don't clear the brain and the toxins build up, that's very inflammatory. Guess what? Our body's health defense lowers inflammation. It's connected to our gut. It's connected to our immune system. Lower inflammation protects the brain. You don't want your brain to be cooking with inflammation, and that's also regulatory.

Our gut health is one of the most important aspects that we're beginning to discover. We're only looking at the tip of the iceberg. Gut health and heart health, superconnected. Gut health and brain health, absolutely connected. Gut, heart, brain, also a new connection that we didn't realize existed before. 

And so the fact of the matter is, our healthy systems are all working in tandem at the same time and together over the sequence of our life, in order to be able to prevent those circulation and dementia problems that can actually occur.

How we live our lives, what we eat, what we're exposed to, the amount of stress that we actually have, how we self-soothe, all these things actually can influence our health defenses and therefore influence our brain. 

So when you ask the question, you know, what actually happens when we start to get dementia, the overly simple explanation that we used to rely on? Look, I went to medical school in the 1980s and 90s. We used to have a simple and incorrect explanation; when you get old, you know, your brain just stops working or operating. Some people have it worse than others. That is just totally the wrong way to think about them. 

[00:29:51] Jonathan Wolf: I think that's how I was brought up as well. Like when you get old, you slow down in general, you can't walk upstairs and you lose your memory. And that's just part of aging. 

[00:29:59] Dr. William Li: Well, the wonderful thing about the research that's being done, the wonderful thing about science is we're beginning to understand how the body normally protects the brain. And if we can do that better, we can do that longer. We can do that more effectively. 

Not only are we able to prevent dementia, and this is really where I think the research is going, we're standing on the precipice of getting enough understanding to figure out how to turn that train away from the brick wall. So can we actually veer people away from developing dementia by protecting blood flow, by having better drainage systems, by preventing leakages and blood clots? Look, that is so important and hopeful for people. 

And because it's tied to diet and lifestyle and stress management, by the way, you know, that's emotional, our emotional health is absolutely critical, important in terms of brain health. 

This means that we stand a chance to within our lifetimes, to be able to actually avoid that brick wall of dementia. And I, you know, as somebody who is like everyone else getting older, I actually feel optimistic that by boosting our body's defenses, protecting our circulation, lowering inflammation, finding ways to actually get better sleep for better drainage, better mental health, all right, all these things will contribute to having longer, more vital brain health.

[00:31:15] Jonathan Wolf: What is starting to happen within, and I think we often hear about things when we go and see the doctor about maybe, like, cholesterol, what's that? We hear that actually diabetes, for example, also is something that is a risk. Could you help us just to understand, hopefully in a level that we can follow, how that is affecting this sort of flow in, you know, these 400 miles of highways and byways as you put it, in our brain?

[00:31:41] Dr. William Li: I told you that blood vessels are like a garden hose to water your lawn. Alright, that's a great way to think about it. But we get much more insight by looking at how blood vessels form to begin with. 

So let me set it up for you, Jonathan. Your Dad's sperm met your mom's egg and you and we all were once just a ball of cells that were forming. We haven't yet formed a face. We haven't yet had arms and legs. We were just starting to become something, not quite sure what it's going to look like yet. 

Well, one of the first organs that forms within a couple of weeks of fertilization in the womb, in your mom's womb, is our circulation. It's one of the first tissues that form, you know why? Because every organ is going to need a blood supply. Right? 

And so what happens is that the circulation, the blood vessels start forming, ultimately 60,000 miles worth 400 in the brain, but they all start forming by these little channels and these channels are tubes, right? 

So now let's think about the garden hose for a second. Have you ever had a garden hose and maybe most people haven't done this yet. I've done it. Take a pair of garden shears and chop that garden hose in half and look at its cross-section. All right, you got the hole in the middle, that's where the water flows through, but there's a wall in the garden hose, and that's why it's thick, and that's why it's strong, and that's why you can drag it through the, through the brambles, okay, and you still, it's just not gonna rip open.

And so, just like your garden hose, our blood vessels, everywhere in our body, from our heart to our brain, okay, have a thick wall. And that wall is really important because that wall is lined on the inside with what I would call seemingly like Saran wrap, you know, the plastic wrap sandwiches are wrapped in it and all that kind of stuff, probably shedding microplastics, not good for the body.

But in the case of blood vessels, really good for the body that that Saran wrap lining…

[00:33:31] Jonathan Wolf: Presumably not made of plastic, I'm guessing.

[00:33:33] Dr. William Li: It's not made of plastic. It's actually it's one of the most important cells in your body. They're called endothelial cells. E-N-D-O-, thelial; T-H-E-L-I-A-L. Endothelial cells are the lining of our blood vessels and they are responsible for allowing our blood to flow smoothly without interruption from our heart where they get pumped from the blood cells get plumped from all the way to our brain. Also to our fingertips, you mentioned to every organ in our body. 

So when the endothelial lining is slippery and smooth, it's a wonderful thing. Now, the lining has got to be smooth, a wall that's got to be solid and thick, right? So if you actually perforate the wall, it's going to start leaking and bleeding.

So you need to have good structural strength. And the reason I'm explaining that healthy part of it is because our diet and lifestyle affects the integrity of this lining, the endothelial lining, as well as the walls of the blood vessels. 

I want to say one more thing about the lining. Have you ever gone ice skating?

[00:34:34] Jonathan Wolf: I have gone ice skating. Okay. May not be very pretty to see, but I have been ice skating. 

[00:34:37] Dr. William Li: That's okay. I'm not talking about a Winter Olympics, but most of us have had at least a chance to lace up the skates and get on the ice. So you know that the first time you go to a rink if you go to a freshly paved rink, they have this machine called a Zamboni machine. You know, it drives out…

Have you ever seen the hockey games? There's this truck that drives out and what this thing is doing is really kind of buffing the ice and heating it. So it's putting some water on it, some warm water and polishing it. Right? 

Now that's clean, fresh ice on a rink. If you were to actually stand at the side of the rink, uh, after it's been cleaned, all right, fresh ice, and you were to throw a sweater on the ice, that thing would be so smooth. It would glide all the way to the other end of the rink. 

Now go have a skating session with 200 people on the ice, you know, including the little kids and the older people and the people who really know what they're doing, you know, the beautiful skaters out there carving up the ice, and you know, you see the little spray of the ice going around. 

Okay, do that for an hour or two, all right, now everyone's taking a break or a lunch break, now take your sweater and throw it on the rink. What happens? That sweater will not move. It gets jammed up on the scraped-up ice. 

So when this happens in the blood vessels, the lining of the blood vessels, the endothelium is nice and smooth, which is what it should be in health. It's like the Zamboni actually prepared our blood vessels to have perfectly smooth circulation from heart to brain to every organ. 

Now, If we have worn down, scuffed up, scraped up lining of the blood vessels, okay, which can happen with smoking, which can happen with toxic exposures, which can actually happen with eating ultra-processed foods and having all kinds of things that can injure this lining, damage this lining. 

That damaged lining is like an ice skating rink after a big hockey game or after a big crowd has skated on it, it's rough, it's scuffed up and when blood flows on it, it tends to stick like that sweater. It's not going to sail all the way through. And when blood cells stick to the lining of the blood vessels, like a sweater on the ice skating rink, that's when blood clots can actually form. 

So you asked me to talk about like, okay, so what actually happens that would set up for a stroke or set up for a problem? Well, it's a scuffing up. That scuffing up can not only set up for a stroke, but it sets up for the accumulation of lipids, cholesterol, fatty streaks, inside the wall of a blood vessel, right? 

[00:37:04] Jonathan Wolf: And this is where the cholesterol that our doctors all get worried about come in is it? 

[00:37:08] Dr. William Li: The harmful cholesterol starts to clog up the blood vessels because the lining isn't smooth anymore. It's not going to kind of glide by. It's going to stick to the side and a little more sticks, a little more sticks, it's going to get narrow. Oh, what happens when you have narrow blood vessels, you're not delivering the blood flow. 

And when that happens to the brain, Jonathan, vascular dementia. So what I just showed you is, you know, with the analogy of the ice skating rink, okay, is what happens between health; perfectly smooth, ready to skate rink for the first time, super smooth, sweater across the rink, to actually damage blood vessels during aging from a lifetime of wear and tear of your blood vessels, where you are not taking good care of that lining. All right. And now blood clots can form and now narrowing blood flow and now dementia. 

[00:37:54] Jonathan Wolf: Will, before we move on to what can you do about this? Which I know all the listeners are like, no, let's talk about what we can do.

But just before we do that, in your book, Eat to Beat Disease, you discuss something called EPCs. And you say they're really important. I have never come across these before, but you have this thing, you call them like cellular seamstresses. I just wanted to say that because it sounded great.

What are they and are they important in this story from your perspective? 

[00:38:16] Dr. William Li: I'm so glad that you brought that up. Okay. An EPC, these are initials. E is for endothelial. And I just told you that's what you call the lining of the blood vessels. P is for progenitor, meaning it's a stem cell. So EPC is a stem cell of the lining of the blood vessels.

[00:38:34] Jonathan Wolf: Which means, what's a stem cell? 

[00:38:36] Dr. William Li: Which means that it's a cell that is held in reserve to help repair and regenerate damaged, scuffed-up lining of the blood vessels. When we're born, we've got about 70 million of these that are left over from, basically, they are the original cells. They're the OG stem cells that help us form our whole circulation in the womb.

But by the time we're born at nine months, you know, we still have some leftover, about 70 million leftover. Those are all packed away, stored away into our bone marrow. So we go through our childhood, our adult life, into our older ages with stem cells packed in our bone marrow. 

And when our blood vessels need to be repaired, the injured lining, that scuffed-up lining, sends a signal to our bone marrow to say, Hey, you know what? I need a little regeneration here, please. A little loving. I need to be fixed here. And what happens is that that Zamboni, the EPC comes out there to repave that scuffed-up ice. So we once again have good blood flow. So super important for maintaining good blood flow between heart and brain and every other organ in the body.

But here's something that is stunningly important. These progenitor cells or stem cells, endothelial progenitor cells, EPCs, also have the ability to turn into other cells as well. EPCs can turn into other cells. That's one of the hallmarks of stem cells. 

By the way, I wanted to make a clarification here. I'm not talking about a stem cell that you can go to the corner strip mall to get injected into your knee or your shoulder. That to me is a commercial venture that's not quite ready for prime time. And I've been involved, by the way, with the biotech industry to try to develop real bona fide cellular therapy with stem cells. It works. But we're not, we're not ready to actually get it mainstream yet. It's, it's still working its way through the development process. 

But our body does it already. And the thing we know about stem cells is that if a stem cell wants to turn into a blood vessel, done deal. If a stem cell wants to turn a liver, it can do that too. And guess what? EPCs as stem cells can also turn into brain cells. So the amazing thing is that we didn't realize until maybe a decade ago, just starting to have the inkling we can actually regenerate our brain. 

So it's long been thought that you know, once your brain tissue dies, that's it. You had a stroke, you can't recover. Wrong. We can actually regenerate parts of our brain. Doesn't happen very quickly? And gosh, if we could actually figure out how to do it better and faster, more efficiently, that would actually. completely turned the tide on dementia. 

So this is an area of research that I work on. It's really, really exciting. It not only repaves the blood vessels, the Zamboni of the good circulation, which we need for brain health and other organ health, but it is also the wellspring for regenerating dementia. 

[00:41:30] Jonathan Wolf: We've teased the listeners for too long. I'd love to talk to okay, so what can you do? And maybe we could take this in two parts, actually.

Maybe we could start with, is there anything you can do if you're actually diagnosed with dementia or maybe someone you love? You know, at that point, is there anything that you can do to sort of slow down the progress of, you know, this awful disease? 

And then maybe we could talk about, you know, afterward, people thinking about this much earlier.

[00:42:00] Dr. William Li: Yeah. Well, look, let me bring it really personal to me. My mother has early-stage vascular dementia. And so, but, but she's quite functional and she's very pleasant. And I'm doing as a doctor and using my knowledge as a scientist to do everything for her. So, I, you know, have been walking the walk on this.

So first you have to assess the brain to make sure you understand to the best of all possible options, like what's actually going on, right? So if you're having trouble with memory and other people are noticing there's issues, you know, you do want to see a doctor, ideally a neurologist to get a checkup of the brain.

A checkup of the brain is very specialized. One of the things, even though we still don't know a lot about the brain, we don't know everything about the brain, scanning and imaging. of the brain can really help. Because Alzheimer's dementia looks different than frontal temporal dementia, which looks different than vascular dementia, okay?

A radiologist, a neuroradiologist, somebody who actually looks at an MRI scan, can actually see the differences.

[00:43:00] Jonathan Wolf: So there is stuff, because I think I was under this impression there was like nothing that anyone could do to even understand what sort of dementia and that's no longer true. 

[00:43:11] Dr. William Li: No longer true. We can actually look at scans and get a better sense of what's actually going on. This is new. And this is why for any further listening, you have to realize that medical research in this area, dementia is such and brain health is such a problem for our society that there's been enormous research poured into this and some really important forward progress being made. 

So scanning to get an idea of what we're dealing with. Number one.

Number two, what I think as an internal medicine doctor, you need to do is go right for the heart. Okay. And you brought this up earlier, we talked about this. You need to make sure the heart is doing its job as best it can to pump blood into the brain.

So are you having rhythm problems? Do you have narrowing of the heart blood vessels? Is your heart not functioning properly? Are you getting enough blood with every single squeeze of the heart, enough to jet up to the brain and get into those 400 miles. Because if you're not tending to that, you're not going to actually be able to service the brain.

And so there are things that we can do for the heart. And by the way, the neurologist, the brain doctor is not going to know the tools to use. So now you want to see a cardiologist and a simple test that can be done to assess the pump function of the heart is called an echocardiogram.

It's basically taking a microphone and putting it right up to your heart. You know, for pregnancy, they put on the ultrasound for the baby. You hear that noise. Well, you can do it for the heart as well. And it gives you a sense of how good your pump is actually working. That's the second thing you need to do.

First brain image, what's going on? Second heart, make sure that pump is working right. It just follows right in line with everything else we're saying. 

Now, the other thing that you wanna be able to do is to see what other conditions, health conditions might be going on. We talked a little bit about diabetes and sugar spikes and insulin problems. We just touched on a little bit. 

Look, diabetes is a disease that the whole body. Okay, it's not just a pancreas issue. It's a disease of every muscle, every cell, every tissue. And so, you need to be able to fix that, right? To be able to optimize it. It's like a mechanic of the body, right? 

When you're actually diagnosed with dementia, you realize it's time to take the body to the shop. To really get a close look at everything that you can have there. Now, It still doesn't answer, How do you fix it? But if you don't have a handle on what's going on, you don't have a chance of fixing it, you’re just throwing darts at the board. All right. 

And what I believe the progress in dementia is, the name of the game, is to get as specific as possible. Because if your heart isn't pumping strongly, there are ways that we can actually get our heart to pump more effectively, more efficiently. Might be a valve, you might need to… a valve problem. You might need to actually fix your valve. All right. That could actually help pump more blood to your brain.

It could be narrowing of the arteries. Well, maybe we need to actually make sure those arteries are less clogged. 

[00:45:56] Jonathan Wolf: And so those changes could potentially sort of slow down the rate of this dementia.

[00:46:00] Dr. William Li: And might even be able to reverse it. The brain does regenerate. So look, not all hope is lost.

You need to actually get at this root cause of understanding the symptoms and not just get the diagnosis and, and throw your hands up and to say, you know, all this loss. No, we need to actually get specific. 

Now, the other thing that's really interesting, and this actually bridges medicine to food is medicine, all right. From the healthcare system to the healthcare we do at home is what can we do to help our circulation, the angiogenesis, the blood flow to our brain, get a little bit better incrementally. Alright.

Remember I told you, 5, 10% narrowing, that's going to make a difference. Alright, so what can we do to actually open up the blood vessels, widen them a little bit to get a little bit better blood flow? Every little bit helps. 

A remarkable research is showing that if we can actually lower blood pressure, we're decreasing the damage, the scuffing up of the blood vessels, the lining of the blood vessels, that sets up for stroke. But if we also allow the blood vessels to widen, Okay, so let's say it's blocked, let's say there's a narrowing. You widen it, now you've actually regained your previous opening, size of opening. You gotta widen them. How do you widen it?

[00:47:14] Jonathan Wolf: Is that possible? 

[00:47:15] Dr. William Li: Yes, it is. Okay, and we can do it with medicines and we can do it with food. 

[00:47:20] Jonathan Wolf: And Will, I think one part I'm taking from this very clearly is that if this is happening to you or someone you love, you should absolutely be going to doctors and really pushing for what's possible because the tech, you know, sort of the understanding has gone on so far.

And you're sharing, you know, your own experience with your mother, which is really powerful. 

What about the non-medical side of this. So the things that you could, you know, be doing at home yourself, or that you're probably discussing with your mother, I'm imagining. 

[00:47:47] Dr. William Li: Right, right, right. So basically, you know, we go to the doctor, for our quote, health care. It's really sick care, we go to the doctor for generally.

But health care is what we do at home. And so one of the things that we're able to do is to use food as medicine to help heal and maintain the health of our blood vessels. That's something that's well established. All these things are sensitive to our diet. We can keep our blood vessels healthy. 

What are some of the things that do that? Well, eating plant-based foods, you know, the polyphenols that come in our colorful vegetables, eat the rainbow. Guess what? That rainbow helps to heal the blood vessels and keep that lining nice and smooth so blood can flow as well as possible.

Omega-3s, you know, we know that marine omega-3s, which you can actually get from, you know, oily fish and even not so oily fish, and even shellfish can actually help to preserve and maintain that slippery, smooth, normal lining of the blood vessels. Okay. Very, very important for our brain health, not just for heart health, right? Omega-3, good for heart health. It turns out omega-3 is great for brain health. All right. 

Flavonols, in the polyphenols. Flavonols, guess what? There's been studies looking at flavonols coming from plant-based foods like cacao. Cacao is the plant source for the material that's used to make chocolate. Dark chocolate has more flavanols and ultra-high flavonol chocolate has been studied and it protects not only heart health but lowers the risk of dementia by improving brain health at the circulation level as well.

Food is medicine is a no-kidding thing. And by the way, the food that we eat also is supportive of our gut health. 

Here at ZOE, you guys have spent so much energy helping to connect the gut health with other parts of our health. And so I want to make another one, which is our gut health and our brain health are connected to our heart health, right?

Gut-brain is now becoming accepted as, you know, yeah, I always knew that. But now we're talking about the heart as a way station between the gut and the brain. So it's gut, heart, brain. Now, how does the gut actually work? Well, you know, good healthy gut microbiome, you want to feed it fiber, you want to feed it prebiotics with polyphenols from your food.

You want to have it, the chlorogenic acid from your coffee, the catechins from your tea. All right, you want to keep it away from all the harmful ultra-processed foods and preservatives and chemicals that, you know, are going to harm your gut microbiome, do more good for that neighborhood of your gut microbiome, it pays us back.

How does it pay us back? Well, it lowers inflammation, for one thing. And by the way, lowering inflammation isn't just good for lowering the risk of cancer and improving the symptoms of autoimmune disease. But remember I told you, inflammation in the brain actually pickles your brain as well. 

So when you have good gut health, that lowering of inflammation, the butyrate, the acetate, the propionate that you may have talked about on other podcasts, actually also helps to lower inflammation in your brain. Gut health, brain health. 

[00:50:49] Jonathan Wolf: And you think that is related to another part of what can lead to dementia, the sort of higher inflammation levels in your brain? 

[00:50:56] Dr. William Li: Absolutely, because most people with dementia have been found to have high levels of inflammatory markers like CRP, C-reactive protein, and other inflammatory markers. TNF alpha, tumor necrosis factor alpha, interleukins, you know. 

This is the stuff of scientists, not of science fictionists anymore. This is the stuff that we're actually able to measure, and actually, some doctors are able to measure that as well. I don't know if in your ZOE system, you're actually able to capture all those inflammatory markers. Surely some of them. 

[00:51:25] Jonathan Wolf: We definitely measure some of them but we haven't had this focus on dementia. So it's really interesting. You're saying this link…

[00:51:33] Dr. William Li: It's going to be connected 100%. And so better gut health, lower inflammation, better heart health, better brain health. Gut, heart, brain. It's starting to be one integrated system. 

[00:51:42] Jonathan Wolf: You've talked a lot about food within lifestyle that can affect dementia.

I feel like the other thing that I've heard people talk about is exercise. And I'm guessing that somehow this links in again through these hearts, these blood vessels. 

Do we understand how, firstly, how important is it as you're thinking about this, whether it's for your mother or for you or me? 

[00:52:04] Dr. William Li: We know that exercise is helpful, but when we think about exercise, a lot of people get put off or saying, you know what, I can't afford a gym or I don't have time to go work out two or three times a week. And they just kind of put it off and they're like, well, that's for somebody else. 

Well, listen, exercise means staying in motion. All right. And our body is designed to stay in motion. It's one of the laws of physics, right? A body that is in motion, stays in motion. So it's one of the things that we actually need to do.

Working out, being deliberate about our exercise is, is good. Cardio is great. If you want to actually, you know, go for spinning or you want to go jump rope, or you want to actually go swimming, or you want to go ballroom dancing, those are all things that actually are good cardio. All right. 

And what happens when you're actually getting a really good workout? Okay. For those of you who might be jogging or running or training for a marathon, you're actually getting your heart working to pump blood. We just talked about this. The heart pumping blood through that 400 miles into your brain is going to be powerful. Better at delivering oxygen and nutrients to that engine, that mastermind that's inside your skull.

So exercise is good for the brain. But there's more to it than that. Exercise also winds up triggering stem cells. You want to get stem cells to actually help repair your organs, and you want to get a jump on that? You want to actually get a little more juice out of your stem cells? You want to exercise.

Exercising helps your bone marrow release these stem cells, regenerative cells, into your bloodstream. And guess where they go? They go wherever there's something that needs to be fixed. Stem cells are very smart. Your brain needs to be repaired, it's going to go to the brain. Your liver needs to be repaired, it's going to go to the liver.

You want to get a little more juice out of the system that's already set up in order to fix you from the inside out. Exercise is really important. 

[00:53:52] Jonathan Wolf: So we had another guest on the podcast talking about, he believed, uh, the reason why exercise works in a sense is the exercise directly might cause some damage in your body, but it triggers all of these healing mechanisms.

And it sounds like you're now sharing a particular way in which we might be starting to understand how that's happening. 

[00:54:11] Dr. William Li: That is exactly it. So let me demystify exercise for people, right? And let's think about it from a young person's perspective, you want to actually be in really good shape. You want to look really good in the mirror. Okay. 

[00:54:25] Jonathan Wolf: You sound just like my son now.

[00:54:27] Dr. William Li: The six-pack, the cut pecs, the biceps, right? The definition, right? So think about it. You got to work at that. You're lifting, you're doing your cardio. Let me tell you what happens when you're exercising. You are straining your muscles.

And in order for your muscles to get bigger, they have to regenerate. So you're straining them. They're breaking down a little bit. It's okay. That's what they're there for. You're breaking them down. And then it's triggering the repair system, which includes stem cells to build more muscle. 

So when a young person wants to build bulk and get more muscular, they're breaking down their muscles so their own body can build it back up, including using stem cells and better circulation, by the way. So you get better blood flow and more stem cells into your system. 

Now look, what's good for the biceps is good for the brain. And so as we get older, you know, not everybody is going to be of the mindset of actually going to the gym and working out, but this is where even a moderate amount of exercise can help.

Even going for a walk for 30 minutes after dinner actually can be really useful. And if you're getting older, if you wind up actually having knee problems, hip problems, back problems, where you're not quite as mobile, this is where actually getting physical therapy to help you out. Right? You know, ask your insurance company, ask your doctor to help you out to get a physical therapist, and maybe you have a neighbor or you know, somebody who's already trained as a physical therapist to help you stay in motion.

Get out of that chair. Even if you need a walker or a cane, stay in motion. It's going to help your body. 

You know, you use the word breaking itself down. You know, I like to, I like to be kinder and gentler to say that, you're putting it through its paces and then afterward it's going to build itself back up and repair itself. Because that's how we're hardwired. 

So much of this, Jonathan, we're talking about is the body's own hard wiring. That actually does what it wants to do. We just need to allow our body to do what it's designed to do and not impede it. 

[00:56:33] Jonathan Wolf: It feels as though what you're describing is sort of the same that you might be saying to me or you about what you should be doing.

Is there anything sort of different for someone who is wanting to try and avoid this happening from somebody who knows that this is starting to happen but wants to try and delay, or even maybe it sounds like potentially sort of prevent the progression? 

[00:56:59] Dr. William Li: Yeah, that's a deep question, Jonathan, because, you know, all of us want to avoid dementia. Of all the things, I mean, you know, maybe cancer is number one, but dementia would be the, the other thing that everybody dreads, fears, and is probably willing to do anything, at least to consider how they can avoid it themselves.

Let me recap some of the high points of what we've talked about in this conversation because these are all the things that can actually protect us. Let's talk about exercise. Stay physically active, even 30 minutes of walking a day is useful. 

Get good sleep. You don't want those toxins to build up. All right, get good quality sleep. Very important, right? So what do you need to do to get good quality sleep besides, you know, being comfortable? Don't eat too close to bedtime. Don't drink too much alcohol. Don't drink coffee at the very end of the evening. All these things interfere with good sleep. Good sleep is required for the glymphatic system to drain the toxins out of your brain. That's what's needed to be done. All right. 

Now, what about having good blood flow? Well, look, something very simple. It's never too late to stop smoking if you're smoking. It's never too late to stop drinking heavily, which can affect your blood vessels and your circulation as well, as well as directly pickle your brain. Alcohol is a toxin for the brain. Okay. Alcoholic dementia is a real thing. So cutting down or cutting out your drinking could be very, very, important part of a lifestyle. 

And then we talked about the gut. Gut health pays off throughout our lives for so many things. Against autoimmunity, against cancer, against cardiovascular disease. Look, it's never too late to start thinking about your gut to protect your brain for the reasons we talked about. 

[00:58:41] Jonathan Wolf: You know, some of the data that some of which is not even yet, yet published about the way in which you can really change your gut health is one of the things I find quite exciting because I think, again, coming back to the sort of story that I was brought up with, which was you're sort of fixed with your genes. There's nothing you can do about it. That's really what's going to determine your life. You're going to get old and incapable. 

And I think what's really exciting, whether it's talking to you or many other people doing cutting-edge research is this sense of there's so much more control. So there's not total control, things can still happen, but you're not just on this pathway that was sort of set by, you know, you told that story at the beginning about like my mom and dad setting me off on a path that you're not just stuck on these tracks with nothing you can do.

That actually, you know, you can be 70 listening to this and you can make changes to your diet, which will really change your microbiome health and, you know, you can give you even then, many more years of healthy life. I find that very exciting.

[00:59:34] Dr. William Li: And it is so empowering to know. Let's just talk about gut health for just a little bit longer because every neurodegenerative disease known from Alzheimer's to Parkinson's to ALS, Huntington's disease, Autism, you know, all of these brain conditions have been tied to abnormalities of the gut or dysbiosis, meaning going away from a healthy neighborhood of gut-healthy bacteria.

Now, we don't know the exact cause and effect. We don't understand exact mechanisms, but what we are really clear on is that there is a clear-cut connection between the gut and the brain in terms of these terrible diseases that everybody wants to avoid. 

So, you know, and by the way, that's been tied to lifestyle and diet. Eat plant-based foods, eat dietary fiber, prebiotics, probiotics, eat fermented foods. Don't eat too much, by the way. Optimizes your metabolism, don't add added sugar that overwhelm your metabolism. You want to lower inflammation, you want to stay physically active, you want to get good sleep. 

The old adage of live well to be well is so true and I mean, it's always been true. But what's different now, Jonathan, is that we now have the power of science. And ZOE's doing some of it.

I mean, I'm amazed when I read the papers that are coming out of ZOE, published in Nature and Nature Medicine. I mean, these are hard-hitting, journals that I publish in for example, I know how difficult it is to get it published in. This is like relentless rigorous scientific data. I pay attention to it and the connections that are being seen between gut health and brain health are incontrovertible.

[01:01:15] Jonathan Wolf: Could I just maybe finish with that last point because we could go on for ages and I wonder if this is almost a tee-up maybe for our next conversation. 

But I did ask a quick-fire question right at the beginning about a link between mental health and cardiovascular disease. And you said yes and we haven't touched on this and I feel like a lot of listeners will be like well hang on a minute that sounded really surprising and powerful could you maybe just give us the little teaser around that to explain that and then I think that might be a whole topic perhaps if I can tempt you back in the future.

[01:01:47] Dr. William Li: Absolutely. The heart is a pump, but a lot of things can go wrong with the pump. You can have difficulty with the pump itself, you can have rhythm problems, you know, arrhythmias. You might've heard of atrial fibrillation. You can have heart failure where your heart becomes really baggy. You can have all kinds of electrical disturbances, you can have valve problems. 

So what I'm trying to paint this picture of is that there's the heart is a very strong organ that's with us from the beginning of life until the end of life, right? That's the final call when your heart actually stops. And so all these things in the heart are important for getting that blood flow to the brain.

Now, blood is only one of the components. The other components are these neurotransmitters that we're realizing that the heart releases hormones that influence our brain as well. 

[01:02:35] Jonathan Wolf: And it's coming out of the heart. 

[01:02:37] Dr. William Li: Comes out of the heart.

[01:02:37] Jonathan Wolf: I didn't know that, I have no idea. I thought the heart just pumped blood around.

I feel like every time I speak to scientists, they're like, and I've now discovered that in my thing, there's all this new stuff. 

[01:02:45] Dr. William Li: So your heart is an endocrine organ that releases hormones that affect your brain and your brain also releases hormones that affect your heart.

[01:02:52] Jonathan Wolf: Amazing. 

[01:02:53] Dr. William Li: These two things are so interconnected that when you actually have problems in any way, shape, or form, the pump, the valve, the rhythm, the electrical system, very easily it affects the workings of the brain.

How so? Depression, bipolar disorder, schizophrenia, and dementia, of course, we're starting to see the nature of this interconnectivity much more clearly.

Now we don't have all the answers, but it is clearly this, you know, we mentioned this earlier today. If you think about the fact that a broken heart, it feels like you've got a broken brain. If you've ever had a breakup in your relationships, and you just feel terrible about it, you feel depressed afterwards.

That sends a signal how connected these two organs are. 

[01:03:38] Jonathan Wolf: I love it. Will, I know I could keep going for ages, but I know we're past time, so let me just try and summarize. We covered a lot of things, so I'll try and make sure that I've caught the heart. 

So, we started off talking a bit about actually what the brain is, and you described the fact that there's these 400 miles of blood vessels in our brain, they're next to every single nerve because you need to get this oxygen and nutrients in. 

And you also said that we have these lymph channels which I had no idea about that sort of clean everything out of the brain they can only work at night sort of when we we fall asleep. And that is a big part of why the healthy heart is so necessary for the healthy brain because you need to be able to make sure all those blood vessels are working really well, but also this drainage can come out really well. 

And then you said that was sort of evolved to protect that blood flow to our brain more than anything else in our body. So basically, you know, we will shut down every other part of our body, but keep that blood into our brain because even a very small drop in that blood flow has this massive impact. 

So you said, like, even with 1% less blood flow, I'm going to feel less sharp. Like with 5%, I'm going to lose some of my thinking ability. And you said at 10 to 15%, I'm going to develop this vascular dimension. And these are sort of small differences that show you sort of how perfectly this machine has to work. 

And then you helped us to understand what's going on within these blood vessels, why there would be this problem. So you said, let's see if I got this right. These blood vessels have sort of a strong wall on the outside, but they're lined with these endothelial cells that let it flow really smoothly like the ice. 

And so you had this vision that it’s like the ice after it's just had the Zamboni machine, all smooth. But actually then our lifestyle ends up scuffing this up. So you start to accumulate all of these scuffs and suddenly the blood doesn't flow very well. 

And you're describing particularly in like these small blood vessels and things in our brain, you can see if it stopped flowing very well, you can end up having this, this vascular dementia. 

And you also shared this brand new thing I'd never heard of, these EPCs. So I've got, I think you said, 70 million of them left over from when I was a fetus, stored in my bone marrow, ready to come out and fix some of these scuffed-up blood vessels. This is a brand new area of research.

But there's only so much you can do. And so if we overwhelm it with all the damage from our lives, it can't cope.

And I think in the second half, you shared this very personal story about how you're dealing with dementia with your mother and actually how you would approach it. And I think there was sort of two halves is what I took. 

One half is, you want to really understand the root cause of this and that these days doctors can do a lot more than maybe I thought and I think many people thought, to assess what's going on and that's both going and trying to understand what's going on in the brain to understand where it's coming from. But you would absolutely then go to the heart and make sure the heart is doing the best job it can to pump this blood in.

And then really understand what are the other diseases that might be affecting this, because if you could treat this, you could potentially, you know, really slow down the progression.

I got the sense from you, you felt, you know, some cases maybe even stop it. 

[01:06:36] Dr. William Li: Yeah, you can actually temper it and in some cases,  you can reverse dementia. I mean, so many of these irreversible diseases, like heart disease, we know you can reverse heart disease now. We, we can't do it every single time, but we know it's reversible.

Cancer, thought to be a runaway disease, you know. We now know we can reverse cancer. We can take stage 4 cancer into stage 0 cancer. I never thought I would see that in my career.

And I think dementia is the same way. I think that it's not a runaway train. I think that the more we understand, the more we're beginning to realize we can not only slow it down, but we can even reverse it in some cases.

It's like vision loss. You know, we never thought you could actually reverse blindness, but actually in some cases, we can actually give people back partial vision that they had lost.

[01:07:21] Jonathan Wolf:  It's very exciting. I can see why you like research science as well, because you've got this edge of how you can transform.

And I think that almost brings us on to the final part, which is sort of the lifestyle ways in which you can either help to prevent this or slow it down or maybe even reverse as you said.

So you started with really sort of food as medicine as like your number one thing. You talked about very much a sort of whole plant-based diet, fiber polyphenols, which are all the sort of colorful foods, so they sort of eat the rainbow. 

You mentioned sort of the marine omega-3 in oily fish is all things that can really help to improve your dementia and that a lot of that is coming, you think because of the role of the gut microbiome, which is sort of sitting between it.

But a lot of this is also how this can affect your heart health and the health of your blood vessels as the way to help to explain how that then links through to the heart. 

You also mentioned though that there's probably this direct link to the way the gut microbiome could lower your inflammation in your body. That can also lower the inflammation in your brain and increasingly it seems like inflammation is another very important part of what affects Alzheimer's. 

And then we talked about the other things you could do. So exercise, really important and a big part of that again is it's helping your heart because if you're having to do exercise, it's sort of like exercise for your heart that has to therefore get stronger.

And I think part of your message was, you know, even if you're not maybe really fit like my son might be or whatever, then actually just staying in motion will make a big difference. So if you can do 30 minutes of walking versus just. being static, that's gonna make a huge difference, not just to your general health, but to your dementia risks.

And then I think some key things that maybe, you know, not all of our guests talk about, but are sort of obviously core pillars of this, like good sleep, don't smoke, don't drink heavily. All of those things will also impact your risk. 

[01:09:10] Dr. William Li: Wonderfully summarized. That's exactly what we talked about.

[01:09:14] Jonathan Wolf: Well, thank you so much. I really enjoyed that. I think that as always, it's a brilliant job of sort of making this stuff quite easy to understand, while also seeing how much the science is changing quite fast. And I hope I can tempt you back in the future. 

[01:09:28] Dr. William Li: Well, thank you, Jonathan. It's a real pleasure and I would love to come back.

[01:09:32] Jonathan Wolf: I hope you learned something today and enjoyed the episode. If you listen to the show regularly, you probably already believe that you can transform your health by changing what you eat. But there's only so much you can learn from general advice on a weekly podcast. If you want to feel much better and live many more healthy years, you need something more.

And that's why each day, more than 100,000 members trust ZOE to help them make the smartest food choices so they could feel better now and enjoy many more healthy years. Combining our world-leading science with your ZOE test results, ZOE is your guide and coach to sustainable improvements to your health.

So, how does it work? ZOE membership starts with at-home testing to understand your unique body. Then, ZOE's app is your health coach, using weekly check-ins and daily guidance to help you shift your food choices to steadily improve your health. I rely on ZOE's advice every day, and truly, it has transformed how I feel.

So, to take the first step toward the possibility of more energy, less hunger, and more healthy years. Take our quiz to help identify changes to your food choices that you can make right now. Simply go to zoe.com/podcast, where, as a podcast listener, you can also get 10% off. As always, I'm your host, Jonathan Wolf.

This episode of ZOE Science & Nutrition was produced by Julie Panero, Richard Willan, and Sam Durham. The ZOE Science & Nutrition podcast is not medical advice, it's for general informational purposes only.