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I'm a scientist, and I study blood vessels. That's where my roots as a scientist lie—in circulation. In fact, our blood vessels are remarkable; we've got 60,000 miles worth of blood vessels packed inside our bodies, and 400 of those miles are actually in our brains. Our circulation is really super important, and as a researcher, I began appreciating the incredible maintenance of our circulation, which are, after all, the highways and byways that deliver the oxygen we breathe and the nutrients we eat. These roads—our blood vessels—need to be maintained just like a road in the countryside. If you don't maintain the road, it's going to break down over time.
As a vascular blood vessel researcher and angiogenesis researcher, we discovered early on that stem cells in our bodies contribute to building and repairing blood vessels. That was how I became interested in and quite familiar with stem cell research in the lab. We actually discovered many chemical substances that can stimulate stem cells to help with their repair. When I began studying food as medicine, one of the remarkable discoveries was that some synthetic chemicals you could order from a research shop could actually stimulate stem cells. However, it was jaw-dropping to discover that natural substances in our food can similarly activate our stem cells and call them into action without necessarily putting out a distress call. We can just gently coax our body's own reserves into action to help repair ourselves in a more robust way.
So, which are some of the top foods we can choose to put inside our mouths that are going to do this? First of all, we are at the beginning of a new era looking at regenerative foods—foods that can stimulate regeneration. I don't have a wrapped gift box to give you with a laundry list of all the foods known to man; we're still doing research on this. But I'll give you some examples. When I talk, by the way, I refer to both laboratory and human evidence, which I think is really important. Something we see in the lab is interesting and can raise an idea, but at the end of the day, it's whether or not it works in people that makes all the difference in the world.
First of all, you might not be surprised that the source of stem cell-activating substances are plant-based foods. Mother Nature's medicine cabinet includes fruits, vegetables, nuts, legumes, healthy oils, and seeds—sources of Omega-3s. Researchers have been mining this pharmacopoeia, looking at what substances in nature can stimulate stem cells. For example, we know that there's a natural bioactive chemical found in plants called ursolic acid. It's found in fruit peels—like the peel of an apple, the peel of a pear, the peel of cranberries, and the peel of blueberries. Most likely, if you've eaten an apple, you didn't peel it; you just cleaned it and ate the whole thing. The peel is a good source of dietary fiber and ursolic acid, which has been shown to stimulate stem cells to come out of the bone marrow and help stimulate regeneration and repair blood vessels. Quite amazing!
There's another substance that has been discovered called beta-D-glucan. This is a soluble fiber known to be good for gut health, and it does a lot of other interesting things that are beneficial for the body. Beta-glucan has been discovered to stimulate stem cells. You can find beta-glucan in mushrooms—both the cap and the stem. In fact, the stem of the mushroom has twice as much beta-glucan as the cap. So, I always tell people, when you're preparing food and cooking mushrooms, please don't throw the stems away because they have a lot of goodness in them. You can utilize them; it's sustainable cooking. Keep all the food parts and use them—they're good for you. Oats also contain beta-glucan. If you're having steel-cut oats for breakfast, for example, that's another source of beta-glucan. Barley has also been studied with beta-glucan to look at stimulating the stem cells that can regenerate your circulation and help repair and grow new blood vessels where they're needed. This is exactly in my wheelhouse to study circulation.
We took this even further to look at the role of other foods that can stimulate stem cells, and one of them is dark chocolate. Dark chocolate has a very particular benefit because, first of all, chocolate is a confection; it's a candy crafted to be sweet and delicious, and most people like dark chocolate. It contains a plant-based food ingredient called cacao. Cacao comes from a tropical tree where the seed pod of the cacao is shaped like an American football. It can be bright yellow or brown. If you pick one up, it's kind of heavy, and you can feel the heavy chestnut-like seeds shaking around. Those seeds are dried, fermented, ground into a powder, and used to make chocolate. If you have 50% cacao chocolate, it has half of the cacao; if you have 80%, it has a lot more, and 90% even more.
Researchers have shown that 80% or higher cacao puts enough of a natural plant-based bioactive called proanthocyanidin into your bloodstream. This has been measured in the clinic. If you give people who have coronary artery disease—people with narrowing and stiff, hard blood vessels—two cups of dark chocolate in the form of hot chocolate for 30 days, and then measure their stem cells and do a flow-mediated dilation (FMD) test to check how resilient their blood vessels are, you see amazing results. At baseline, these people are not doing well, but after 30 days of consuming two cups of hot chocolate, researchers found that the proanthocyanidins not only got into the bloodstream but also doubled the number of stem cells circulating in their blood vessels and improved the resiliency of their blood vessels by twofold. That's just from two cups of hot chocolate over the course of a month.
That's a really interesting point you made at the end—the quality matters. You could get a hot chocolate powder from the supermarket that is full of additives and sugar and has a very low concentration of cacao, or you could get a completely different one with minimal ingredients and high levels of cacao, as you say, 80% or more. That's the nuance that sometimes we miss when we talk about food. Hot chocolate is not just hot chocolate; it depends on the quality.
That's right. The stuff you get in a packet at the grocery store might taste great, but if you look at the ingredient label, you'll see added sugar, emulsifiers, artificial chemicals, preservatives, and stabilizers. That's probably not something you want to put in your body. If the ingredient label creeps you out, put it back and look for another choice that has minimal ingredients. Even better, if you're committed to using a natural way to improve your health, make it yourself. You can even make it without dairy, which is really interesting. You can create a tasty super dark chocolate.
A lot of people don't know this, but the history of cacao and chocolate goes all the way back to the Aztec civilization, where it was considered so valuable that it was used as currency at one point. It was also used for its medicinal and ceremonial value. This is why, when you're at an airport and tempted to buy a bottle of water and chocolate, you should remember that the healthful chocolate we're talking about is really about paying attention to the quality of what you're putting into your body because that influences how your body responds to it.
It's fascinating. I was reflecting with a friend over the summer on how certain things, like cacao and alcohol, were often used in traditional cultures in very different ways than we consume them today. They were ritualistic and ceremonial. Cacao probably wasn't used daily; it was reserved for celebrations and rituals. I think the same applies to alcohol. Yet, we love to take those things and shove them into our daily lives. I feel we do that with many things; we change the way we consume them compared to how we have traditionally.
Absolutely. If you think about how we approach food today, it's often treated as a commodity. We have this consumer mentality where we look for the cheapest, most convenient, and tastiest options, influenced by advertising. We've gotten further away from what I think is central to our humanity when it comes to food: appreciating it, savoring it, and respecting it. If you look at broader planetary concerns—how we grow our food, how we treat the land, and how we farm—all of those implications stem from the fact that we don't respect food as much anymore. We're stripping away the land, getting the cheapest food possible, and packaging it in ways that aren't very costly, putting colors on them like clickbait in nutrition. I think this takes us further away from our humanity.
I'm bringing this up because, as you're talking about tradition, ritual, and ceremony, I think one of the things we're beginning to appreciate as the world becomes more distressed is that there's great value in being more appreciative of what we have and respecting food. We need to think about our food differently, including where it comes from, how it's handled, and ultimately how we're preparing it and putting it into our bodies. It's a continuum that pays off when it comes to our health.
Thank you for sharing that. Now, Dr. Lee, so far, the foods we've mentioned in relation to stem cells include ursolic acid, which you can get in fruit peels, beta-D-glucan from mushrooms, oats, and barley. You've also mentioned cacao and dark chocolate and how beneficial that can be. One thing I've always noticed about your approach is that you make food exciting. You talk about all these different foods and pathways and how we can be active participants in our health by choosing foods that activate these incredible pathways. How do you square that with the fact that many people these days eat an excess of calories? If someone hears what you're saying and they're already eating an excess of calories and they start adding in dark chocolates, hot chocolates, oats, and barley, how do you help people navigate that? An excess of calories is problematic for health, even if you are adding in some of these powerful foods.
This is a great topic of discussion, and I'm very passionate about the idea of not overeating or over-consuming. Overconsumption is a relatively recent phenomenon—within the last 70 to 80 years, especially in modern society. If you go further back, most people were still scrambling to get enough food; they were hungry most of the time. It's only really in our modern day and age, particularly post-World War II, that relative prosperity in developed countries allowed us to overconsume food regularly.
I want to talk about metabolism for a moment because this is where it connects to healthy eating and overeating. I want people to think about metabolism, which relates to weight gain, obesity, diabetes, and other chronic diseases ranging from cardiovascular disease to cancer to dementia. Our metabolic health is maintained by our bodies like a machine. In fact, our metabolism is like the operating system on your computer. There are myths about metabolism, one being that it's just a roll of the dice; we get it from our parents. That's not correct.
Many people say, "Oh, my sister was so lucky; she was born with a fast metabolism. She's skinny as a stick and can eat anything. I was born with a slow metabolism and have had to fight with food my whole life." This is a common sentiment, but it's not true. If our kidneys work the same, our eyesight works the same, and our nerves work the same, what makes you think metabolism is a crapshoot?
Our metabolism is hardwired in our bodies to operate the same way. If you and I bought the same model of laptop from the same store at the same time, plugged it in, charged it up, and hit the button at the same time, the operating system of your laptop and mine would be exactly the same out of the box. The human metabolism is similar.
I'm telling you this because it's important to think about the consequences of abusing our metabolism over time. When you abuse your metabolism, you can slow it down and cause problems. Overconsumption of calories is one way to abuse your metabolism. Think about it: if you overload your metabolism by eating more calories, you're putting stress on it.
Calories are our fuel, just like fuel for your car. If you overload the fuel in your car, what's going to happen? Usually, gas stations have a clicker to prevent you from overloading your gas tank. In the body, we don't have that clicker, so we can easily overflow our own fuel tanks. Our fat is our fuel tank. When you overload your fat, you keep filling it up, and your stem cells will create more fat tanks. Overloading your caloric intake puts stress on your metabolism, which can derail your health.
It doesn't matter if you eat healthy food or junk food; overloading is not good. But whatever fuel you have, you would prefer to have good quality fuel. So, going back to your point about overconsumption, I always tell people who are struggling with this to take stock of the quality of the food they eat. What quality fuel are you loading into your body?
I suggest keeping a food diary for a few days or a week to see everything you eat. This can help you identify low-quality fuel items. Then, I ask them to consider how much they actually eat. This is trickier because most people overeat. We're almost trained to overeat. If you're loading your own plate, I always tell people to take only two-thirds of what they would normally take. If you're serving yourself at dinner, take only two-thirds and leave a third back on the platter.
Load the vegetables on first, then take only two-thirds. Eat slowly, and if you're feeling full, stop eating. You don't have to clean your plate; it's okay if you don't finish everything. I also tell people to try not to snack after dinner because that can lead to overloading your body. These are all little tips to help people take those first steps in their health journey.
I really appreciate that; it's very useful. You mentioned quite a few things that are worthy of conversation. One was about the wealth of information that now exists for people—the overload of information, even good quality information. It's a bit like the overload of good quality healthy food. If you are consuming lots of healthy food, the analogy with the car is a nice one. You can't really overload your car's fuel tank because there is a stopper that prevents it. Just imagine if that wasn't there. If you start spraying petrol all over the internal workings of your car, even if it was premium fuel, it would be a problem. It's a little bit like when we have visceral fat accumulating in our bodies, isn't it? This harmful fat, especially beyond a certain point, starts to send out inflammation and damage those organs, increasing our risk of early death and disease.
I think it's a great analogy. I want to talk about this era of information overload because people can consume all kinds of information now. They can read books, watch your YouTube channel or mine, and get all this information. Yet, with all this information, many people are confused. They say, "Dr. Lee, you're saying this, someone else is saying that, and someone else I followed online is saying this." My feeling is that, yes, we want to listen to experts and get their advice, but we also have to go inward and ask, "Which bit of this advice works for us?" I heard Dr. Lee say this, Dr. Chasi say that, and Dr. whoever else say this, but when I eat like that, that's when I feel good. I feel we're missing that these days. We've outsourced our inner expertise about our own bodies far too much to external experts, and I think that's a massive problem that we're not talking about enough.
You're absolutely right. Our own health is incredibly personal. What makes me feel good when I make a food decision, how I prepare a meal, or how I eat is very personal to me. How I feel about my eating habits, how much I eat, and when I eat are all important factors for health. But how it works for me is going to be different from how it works for you or anyone listening. Knowing thyself—self-knowledge is true knowledge. Every individual needs to recognize their own self-knowledge to advance in their health journey.
We spend so much time consuming information externally and not enough time contemplating what makes us tick. Taking a walk can be a solo activity that allows you to exercise and be in motion. If you do it by yourself, it's an opportunity to calm your mind and think about yourself. If you meditate or practice breathing exercises, it's another way to center yourself.
While we give a lot of recommendations, it's equally important for anyone pursuing better health to take the time to understand how they feel when they're healthy and when they're not. Everyone has their own path. Personalized medicine is where all medicine is going. One size doesn't fit all. Every individual is going to respond differently to the same treatment.
When we were training, we had common patterns and themes. One theme is that you take an antibiotic, write the same dose, treat for the same number of days, and you're done. It's like a cookbook that works the same way for everyone, but that's not true in medicine, nutrition, or exercise. The idea of personalization and knowing oneself is vital.
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I want to say one more thing about this whole information overload. This is true for children who are consuming information in a very particular way. A typical kid in high school or junior high school, maybe even younger, is on their phone scrolling all day long. They're watching TikTok, looking at various things, and communicating through Snapchat. It's very externally focused and consumptive. There's an algorithm that feeds you more of what you seem to enjoy seeing, but that doesn't help you get to know yourself.
It also doesn't force you to consider the source of your information. I think it's really important for anyone interested in health information from experts to try not to listen to everybody and everything. Pick a few trusted voices. It's up to you to decide how you connect with them. One of the big challenges of the online community is that anyone can deliver information. I believe that people trained in health, who do research, and who communicate carefully are important. Words matter.
You can narrow your focus. Look for two or three people you resonate with and like their voice, but check their backgrounds to see if you think they should be trusted resources. This way, you're not getting wild ideas that may not be correct.
Thank you, William, for sharing that. It's great life advice beyond food in terms of how to navigate the modern world. I feel very passionately about the idea that we've got to start tuning into ourselves more. Yes, there are core dietary principles we can share, and you've written two fantastic books on many of these things—foods that people can choose to help improve their health for whatever reason they want. But ultimately, you've got to try this stuff out for yourself and really pay attention to when you feel good, what pattern of eating suits you, when you don't feel bloated, and what is going on in your life when those things happen. That's the ultimate knowledge—self-knowledge, self-awareness, and insight. That's wisdom.
If I reflect on my career, the patients who truly transformed their lives for good were those who, at some point, converted the advice from the outside to figuring it out for themselves. They said, "No, I know what's best for me. I know which way of eating works best for me," having heard from the experts but then becoming their own experts. That's something I really want to help people do more and more.
Going back to foods, Dr. Lee, we mentioned a few foods already that can help our stem cells. What about olive oil? Does that have any relationship with our stem cells?
Absolutely! Olive oil is a healthy fat; it's a plant-based food that comes from olives. It contains many bioactives, some of which have been identified. The ones that have been best studied include hydroxytyrosol and oleocanthal. For people listening, if you're a science geek, you can write this down, but just know that these natural substances have powerful effects on our bodies. For example, hydroxytyrosol has been shown to be protective of our stem cells. When you consume olive oil and get these polyphenols into your bloodstream, they act like police escorts to help your stem cells get to where they need to go in a safer way.
Why do they need to be protected? There’s a lot of oxidative stress in our bodies. Oxidative stress can come from fumes we breathe, vaping, off-gassing from carpets, artificial flavorings and preservatives in our food, and cleaning materials. All these chemical exposures cause oxidative stress in our blood, which can damage our stem cells. Hydroxytyrosol is one of those natural molecules that protect your stem cells against oxidative stress. It's like a police escort that helps your stem cells get to where they need to go safely and efficiently.
When you think about olive oil, there are multiple reasons to consume it. You just mentioned the research around stem cells. I'm sure if I asked you about longevity, inflammation, or blood vessels, you could also talk about the benefits of olive oil. But how do you recommend people consume it? Are you a fan of it being cold on salads and vegetables, or do you think it's okay to cook with olive oil as well? This is an area of confusion and controversy online, so I'd love to get your take on this.
I want to be very clear: olive oil is, of all the cooking oils, a healthier choice to use with meals. You don't have to cook with it, but you can cook with it. There's a myth that olive oil has a low smoke point, so you shouldn't do high-heat cooking. As it turns out, olive oil's smoke point is almost the same as canola oil, which is used for frying. You shouldn't reuse olive oil at high heat, but cooking with it in a wok or sautéing is perfectly fine.
In the Mediterranean, I don't encourage people to eat a lot of fried foods because frying creates side products called acrylamides, which can be potentially carcinogenic. However, everyone likes crispy food occasionally. In the Mediterranean, they fry foods in olive oil, and the polyphenols get into the food, making something that's not that healthy a little bit healthier.
You can cook with olive oil; you just have to like the taste of it. The quality of the olive oil is really important. Many people don't appreciate this, but when you go out to buy olive oil, it can be overwhelming how many different choices you have. You might go for the less expensive one or the one with a more attractive label. I always recommend getting the highest quality olive oil.
Look for olive oils made with only one kind of olive, called monovarietal olive oil. There are two reasons for this. When olive oil makers make olive oil, they pick olives when they're ripe off the tree, crush them, and spin them in a basket. The oil floats to the top, and the watery stuff goes to the bottom. They scoop the olive oil off without filtering it, which is why you get little bits that are green. Extra virgin first-press olive oils are always going to be tastier, and you're going to get that peppery taste, which is where the polyphenols come from.
Many olive oil producers cut their oils, adding other oils to it. Sometimes they mix different types of olive oils together, often the cheapest ones they can find. To avoid this, look for monovarietal olive oils pressed with only one variety of olive. These usually come from a single farm, which guarantees the quality of the olive oil.
If you like Spanish olive oil, look for monovarietal Spanish olives made with the picul olive. If you prefer Greek olive oil, the highest polyphenols among Greek olives come from the Koroneiki olive. If you like Italian olive oils, the highest polyphenols are found in Moraiolo olives from Umbria.
I tell people, if you're going to buy olive oil, why not get the highest quality? It's fuel, and you want it to taste great. If you're going to dip some bread in it or drizzle it on pasta, why not get the best with the highest polyphenols?
By the way, some people have reported that olive oils are not good for your blood vessels and can damage the lining of your blood vessels. That's all bunk. As a blood vessel expert and someone who studies food as medicine, we've studied this. It's a theoretical idea that got put together but ultimately isn't true. Olive oil is perfectly fine and very healthy for your blood vessels—quite the opposite.
As for how much to eat, studies show that the average amount of healthy oil to consume per day is about three to four tablespoons of olive oil. That's a fair amount. If you're not an olive oil consumer, take a measuring spoon and put three to four tablespoons into a dish. It's not that much. If you're scrambling eggs with it instead of butter, making a salad dressing, or roasting vegetables, you'll easily get three to four tablespoons of olive oil into your system.
Brilliant! That's super practical. So essentially, a lot of advice there on olive oil. If people are struggling with the cost of things, is your advice to get the best quality olive oil that you can afford?
Absolutely! By the way, you can buy things on the internet as well. If you search for monovarietal picul or Koroneiki or Moraiolo olive oil, you can find good quality manufacturers or suppliers. Order it online. People spend a lot of money on various things, but getting high-quality food for yourself is one of the best investments you can make.
In Europe, it's a lot better than in the United States. People buy junk food and spend money on unhealthy things. Getting healthy, high-quality food is one of the best investments you can make.
I completely agree. Everyone has different financial situations and means, but something profound happens when you consciously decide that the food you put in your mouth is of top importance. I made that decision a few years ago. If I'm going to be the best human being I can be—the best father, husband, and capable human being as I age—then the quality of the food I put into my mouth day in and day out is important.
It doesn't mean you're never going to go off track, but there's something powerful about making that decision. Once you live with that decision for a while, other things start to change. I love eating out as much as the next person, but I've become a lot fussier these days. I prefer eating in because when you tune into what good quality food tastes like, often when you're out—though there are some great restaurants and cafes—I just don't feel that good afterward. It could be the oils they're using to fry or whatever it might be.
I'm not saying that applies to anyone else, but for me, I much prefer to eat in these days when I can.
I totally agree. I also think that having some self-compassion is an important component. If you've decided to try to be as healthy as you can, don't feel like it's a strict religion or a military camp where you can only do one thing. We're all human; we have to enjoy ourselves. We need enough compassion to realize that it's okay to wander off the path occasionally, as long as you get back on it.
I try to lower people's stress levels when it comes to living a healthy life by saying these are guidelines. They should feel better when they're following them. It's up to you to take that path. Rather than making people feel fear, guilt, or shame about food, I try to give them permission to live a little. Every now and then, you're going to do something you really enjoy. If you spend more time doing things that are good for you, your body will be strong enough to rebound from the occasional indulgence.
It's like driving on a road. Following the rules of the road helps keep you a safe driver, but who doesn't speed every now and then? Speeding can kill you, but sometimes you need to get somewhere quickly. It's okay to go a little faster than the speed limit. I encourage people to be self-compassionate and give themselves permission to choose, with the encouragement to make more good choices more often.
I completely agree. Just to be super clear, I've really gotten to that point about eating in compared to eating out in the last couple of years. I've been on this journey to improve my health for over ten years now. You start off where you can, and bit by bit, you go off track and realize, "Ah, I feel better when I'm like this."
Last week, I was away for work from Monday afternoon to Friday evening, so all my meals were out. I was completely fine and able to function, but since I got back, I've been like, "No, I just want to eat in. I want to cook my own food."
I think that's a really important point you mentioned about blood vessels in relation to olive oil. We've spoken a lot about stem cells. If we could shift the focus to blood vessels, olive oil is a food that can help us with our stem cells and our blood vessels. Let's set the scene again like we did with stem cells. Why is the health of our blood vessels so important? What do we get wrong when we think about blood vessels, and how can we choose specific foods that will enhance the health of those blood vessels?
I mentioned earlier that there are 60,000 miles worth of blood vessels packed into our adult bodies. If we were to pull out all the blood vessels and line them up end to end, we would form a line that could wrap around the Earth twice. These are the highways and byways of everything—oxygen we breathe, nutrients we eat—they deliver to every single organ in your body. This is really critical. In fact, no matter what else you think about in terms of your health, if your blood vessels are healthy, you are at a great starting point to optimize the rest of your health.
If your blood vessels are unhealthy, you'll be far behind. It will be impossible to optimize your health in any other part of your body. This is true when you're a child, a young adult, and especially true as we get older—around 40 and above. We need to start paying super attention to how well our blood vessels are functioning.
The good news is that we often think about our blood vessels as passive, like plumbing that gets clogged with lipids or plaque or atherosclerosis. This ultimately leads to a heart attack, stroke, or leg dysfunction when you have clogged arteries. However, our blood vessels are anything but static. They're incredibly dynamic.
What that means is our bodies manage to maintain our blood vessels to keep them optimized all the time. Something that keeps our blood vessels healthy and dynamic is the inner lining of the blood vessels. Our blood vessels have a sleeve, like a layer of plastic wrap, that is extraordinarily slippery. We call it the endothelial layer.
If you think about a garden hose and cut it in half, looking down the middle, you see the hole. If you were to take plastic wrap and coat the inside of the garden hose, the water would slide through easily. In our blood vessels, that same kind of wrap is made of living tissue called vascular cells. It's extraordinarily slippery—so slippery that I give the analogy of an ice skating rink.
If you've ever been ice skating, you know that when you get on the ice, it's really slippery, and it's hard to keep your balance. That's what blood vessels need to be like so that all the blood cells winging through our bodies don't stick to the walls. They just keep going.
If you've ever been ice skating, you know that after the ice is cleaned, there's a machine called a Zamboni that polishes the ice between sessions. When the ice is new and polished, you could throw a sweater on it, and it would glide all the way across. After a hundred people skate on it, the ice gets scuffed up. If you throw that sweater on again, it won't slide; it will stick.
We want our blood vessels to be polished and smooth. If you don't treat your blood vessels properly, high amounts of salt, sugar, and unhealthy saturated fats can scrape up the lining. That's the difference between having a sweater glide across the ice versus having it stick. When blood cells stick to the ice in your circulation, that's not good.
That stickiness can start to build up layers, which is how blood vessels get narrowed. One of the things your body tries to do is use those stem cells we talked about earlier to repair areas of the ice where a piece might have come off and smooth it out again. We can restore that healthy layer. It's quite amazing how dynamic our blood vessels are.
When we need more blood vessels, our bodies can naturally grow them where they're needed and stop when there are enough. If there are too many blood vessels growing, our bodies can also trim the extra ones. It's like a landscaper looking at a golf course and maintaining it perfectly. If there are patches that need more grass, they'll put the seed in and grow it. If the grass grows too high, they'll mow the lawn.
That's how our blood vessels are maintained. That process is called angiogenesis—how blood vessels grow and stay healthy.
It's such a beautiful image to think about the inside of these miles and miles of blood vessels in our bodies as either being smooth, allowing blood to travel with no friction, or having bumps and lumps that make it more difficult. We don't naturally think about food and blood vessels, but we do think about our brain health, cognition, mood, skin health, and immune system without realizing that if you don't have healthy blood vessels, you're not delivering oxygen to all those critical areas.
Healthy blood vessels mean a healthy heart and a healthy brain. It's a core tenet of optimal health to have healthy blood vessels. Of course, many people talk about exercise and moving your body as a factor in maintaining those blood vessels, but I've heard you say in an interview that one of your pet hates is when people say exercise is the only thing that's good for heart health. The food you consume is also very important for blood vessels.
Can you give some examples of what kinds of foods directly impact the health of our blood vessels?
One thing we talked about already is olive oil, but I also want to mention that you can eat the whole olive. You get the fiber from the olive and more polyphenols from the flesh. Other foods that are clearly heart-healthy include leafy greens, which have dietary fiber and polyphenols.
The Brassica family of vegetables, like broccoli, kale, Brussels sprouts, bok choy, and Swiss chard, are great for our metabolism. They help lower harmful body fat and inflammation, which is critical. You can sauté these vegetables with a little olive oil and garlic for a delicious dish.
When you eat these delicious foods, the polyphenols and sulforaphanes get absorbed into your bloodstream. They protect your heart by lowering oxidative stress and inflammation. The dietary fiber from leafy greens doesn't get absorbed but travels down to your gut microbiome. Feeding dietary fiber to healthy gut bacteria leads to the production of short-chain fatty acids, which further lower inflammation.
Inflammation is damaging to our blood vessel health. If you have high inflammatory markers, like C-reactive protein, you have inflammation everywhere in your body, including in the lining of your blood vessels. This is a bad thing to carry around.
Leafy greens, with their polyphenols and dietary fiber, can collaborate in a beneficial way to promote heart health, starting with improving the health of your blood vessels.
Any other foods that we forget about when thinking about our blood vessels that you would like to highlight and encourage us to bring into our diets?
It turns out that two beverages—tea and coffee—have polyphenols that are heart-healthy and beneficial. Tea contains catechins, specifically EGCG (epigallocatechin gallate), which has been well-studied. Coffee has many different polyphenols, one of the best-studied being chlorogenic acid. Both of these beverages are heart-healthy and good for blood vessels for similar reasons: they protect your blood vessels against oxidative stress, lower inflammation, and improve gut health.
If you combine these beverages with leafy greens and blood vessel regenerative foods like barley with beta-glucan, mushrooms, or a little bit of high-quality dark chocolate, you see that the net consumption of these foods exposes our blood vessels to the nutrients they need to maintain the roads in our bodies—our circulation.
You mentioned some benefits of green tea. I know you often speak about drinks that longevity populations consume: tea, coffee, and water. You've also made a video recently on your YouTube channel about drinks that can help with metabolism and potentially remove visceral fat from organs like the liver.
It's quite an interesting concept for people because I think most people think about their weight and excess fat as primarily being in a calorie deficit—essentially consuming less than they're burning off. Over time, this leads to weight loss. I know your last book covered this in detail, but can you help us understand how important that is versus particular drinks like green tea or coffee that can really help boost metabolism?
There are many ways to help our bodies optimize metabolism. We talked about one earlier: don't overconsume calories, and whatever you do consume, make it high quality. That snapshot captures a lot of what we've discussed.
However, there is a hidden mechanism in our bodies that can help burn down extra harmful body fat. This allows us to eat foods that can actually trigger fat burning. Now, that sounds contradictory, right? If you want to lose fat, you want to eat less. But actually, some foods can trigger fat burning.
Before I tell you the foods, I want to explain how this works. The popular fad of cold plunges is healthy for your metabolism, and it does work. When you expose your body to cold, the temperature drop triggers a special kind of body fat that's not harmful but beneficial—brown fat.
Brown fat is not a fat that most people are familiar with. Most people know about white fat, which looks white under the microscope. White fat is the lumpy, bumpy fat we think about. It can be subcutaneous fat under the skin or visceral fat packed inside our organs. Visceral fat is dangerous because it can be highly inflammatory.
Our bodies have evolved a natural way to tame visceral fat through brown fat. Brown fat is thin and not close to the skin; it's attached to the muscle deep underneath. We have a little bit on the side of our neck, under our breastbone, and between our shoulder blades.
Brown fat hangs out quietly in the background, but when exposed to cold temperatures, it fires up and generates heat. This evolved in animals that hibernate. They get fat in the fall and then hibernate in the winter. Brown fat keeps them warm and provides energy by drawing down fat.
Humans also have this mechanism. It wasn't until the 1930s that we realized humans have brown fat. It was discovered through PET scans, which light up when brown fat generates heat. This was observed in people getting scans in the winter, not in the summer.
Cold plunges are beneficial for metabolism because they fire up brown fat to burn down harmful white fat. Brown fat is good fat that burns down excess white fat, which is bad fat, and lowers inflammation.
There are some drugs that can do this, but I don't recommend them because they have side effects. The good news is that certain foods can also activate brown fat. Green tea and coffee both contain polyphenols that light up brown fat to burn down harmful excess white fat.
So, instead of just taking one approach, why not do everything you can to increase your chances of success?
That's right. You can do it in natural ways that don't force you to take extremes. One way is to put less on your plate. That's low-hanging fruit—easy to do. Whatever you put on your plate, make it plant-based and as healthy as possible. Don't eat too much saturated fat, salt, or added sugars.
You can also swap out foods that promote fat gain for those that promote fat burning. For example, swap soda for tea or coffee. Now, instead of building fat with empty calories from soda, you're drinking a beverage that can light up your brown fat and burn down harmful visceral fat.
Simple swaps can make a difference. If you're planning meals, it can be overwhelming to figure out what to buy. Let me run down some interesting foods shown in human studies to burn down harmful body fat.
Onions have quercetin, mostly packed in the outer layer. Don't peel off too much of the outer layer because that's where most of the fat-burning quercetin is. Red onions have more of the good stuff than yellow onions.
Tomatoes contain lycopene, which helps burn down extra body fat and can even shrink your waistline. Strawberries have been shown to burn down harmful visceral fat. A can of inexpensive white beans eaten for five days out of seven can shrink your waistline by one inch.
Carrots can also burn down harmful visceral fat. Eating the equivalent of three medium-sized carrots a day can turn on thermogenesis. Seafood is another option if you eat it.
I'm an omnivore; I eat mostly plant-based foods and only a tiny amount of meat.
That's a great list! Thank you for sharing all of that. It's been a really insightful conversation, Dr. Lee. I appreciate your time and the wealth of knowledge you've shared with us today.
Try to choose high-quality food, whatever it is I'm eating. Seafood actually contains omega-3 fatty acids. Guess what? That's another healthy fat! A lot of people don't realize that omega-3s originally come from plants; they come from algae. So, the plants of the sea are where they're originally coming from, and they wind up in seafood. Most people think, "Oh, I have to eat salmon. I'm sick of salmon," or "I have to eat tuna; it's expensive." You know what? It actually turns out that lesser fish, more inexpensive fish, and shellfish also have omega-3s. Sure, salmon has a lot, but you can actually look at cod, flounder, or other types of Mediterranean sea bass. They all have omega-3s that are healthy for you. So do mussels and clams. If you eat shellfish, squid, octopus, and shrimp, they all have omega-3s. That's another way, if you live near the coast or you're someone who enjoys cooking, to kind of live it up with seafood. That's also a way of turning on your good, beneficial brown fat to burn down your harmful excess white fat.
The underscore here, though, is that even though I mentioned a lot of ingredients, you have to remember that how you prepare the food is important. If you don't want to be putting a lot of butter into it, or a lot of salt, that can damage your blood vessels. You don't need to steam everything, but you want to be mindful; you're not going to fry everything either.
Yeah, Dr. Lee, you have such a wonderful way of talking about food. You clearly explain the science, but your passion infuses everything, and it kind of leaves us all with this idea that the foods we choose can be a creative pursuit for us. Yes, it's for our health, but it's like an artistic endeavor that we can play with to actually find the things we can utilize to improve our health. So, I really appreciate that. I also appreciate that list at the end there; many of those foods you recommended were very affordable, which I think is something to be very aware of these days.
To finish off, Dr. Lee, if someone has heard our conversation and they're like, "Okay, Dr. Lee, I hear what you're saying. I understand the science there, but I don't really need to change much. My life is going pretty well. I think I'm in a decent place; I can function at work." Why should I start changing the food that I put on my plate? What would you say to them?
Well, listen, my current research, the area that I am working on—my books are all about the work, the research I'm doing. I'm not reaching for topics to cover; I'm writing about what I'm researching. Right now, I'm researching healthy aging, including longevity, and I'm researching brain health and all the things connected to brain health. One of the reasons that I would answer someone asking the questions you just stated is: Listen, if you are doing pretty well now, keep it up! But what the exciting research is showing is that if you push a little bit harder and try to buff up some of those areas, even by a little bit, you could actually be doing yourself a service to improve your brain health as you get older in remarkable ways.
For example, here's one: "I'm eating plenty of fruits and vegetables; I'm fine." Well, you might be amazed to know that one cup of ripe strawberries a day has been shown to actually reduce cognitive decline in human clinical studies and also reduce the depression that comes with cognitive decline. What's in a strawberry? You've got ellagic acid and anthocyanins—these are natural molecules that we're discovering. So, we're discovering the benefits to brain health of strawberries. Maybe you're eating healthy, but the next time you walk by a market and see those strawberries, you might want to do a double take and go back and say, "You know, I'm going to try some of those now."
These little tiny extra tweaks—if you're somebody who's already healthy—think about what you're doing. If you feel pretty good now, great! Now it's time to level up and see if you can do something to make yourself even better in the future. I think thinking about what we do now having an impact in the future is kind of like saying, rather than putting all my money under my mattress—which is sort of a Depression-era thing—why don't we invest our money in some good things? You're going to have the money anyway, but where are you going to put it? Under your mattress, or are you going to invest it in something that's going to grow? I think that making healthy food choices is a way of growing our health. By growing your health, you're really investing and becoming wealthier inside and out in terms of brain health, which is a huge dividend for you.
I mean, think about it: all this discussion about longevity, mitochondria, glucose spiking, and trying to get your serum levels right—like all the millions of things that people are talking about now. I have one thing to say to that: Who wants to live longer if you're not able to have good brain health? You could live to 150 or 200—go for it! But if your brain isn't working, it's not worth living for. That's why I think that in this quest to live long, we want to live well. The choices you're making now are remarkably finding that we can actually improve our future selves in ways that are profoundly important: our vision, our brain, our muscle strength, our ability to enjoy life. You mentioned the word "passion." We want to really enjoy every year that we get. I think that the good choices, those little tiny tweaks we make, can make a big difference.
Yeah, I love that! Thank you so much for that impassioned plea at the end of our conversation. Where would you direct people who want to learn more? Obviously, you have two wonderful books, but you also have an online course that people can do, I believe.
Yes, so first of all, I have a YouTube channel. If anybody's interested in YouTube, check out the content because I'm putting out stuff that people are asking me all the time. I can't always get in front of a live audience, so I'm like, "Okay, I'm just going to put it up on YouTube." My YouTube channel is Dr. William Li. My website is also the same: www.drwilliamli.com. I'm on social media. However, if you want to really do a deep dive with me, I'm happy to accompany you and be your guide on a health journey. I do an online course, which is a really deep dive for a month at a time with a lot of interaction. I teach you about your body's health defense systems. It's called the "Eat to Beat Disease" online course. I've been doing it for more than four years now, and I'll tell you what's remarkable: there are more than 4,000 people from 80 countries that have taken it. One of the sources of pride I have is the impact it's having, being able to reach people from all around the world.
What I try to encourage my students to do is not only to learn these practical tips and how they can help make daily moves to improve their own health, but I also encourage them to share their insights with their family and friends. Then they become the expert; they become the person who can communicate something important based on science and evidence that they've learned in order to help other people become healthier as well. Living life with purpose is something that's very satisfying to most of us, certainly to me. I try to share that with people by saying, "Listen, if you know how to live a little bit healthier and you can share it with your kids, your neighbor, or your friends, and then they become a little bit healthier, you've actually made an impact on the world."
Yeah, I love it! Dr. Lee, you're doing fantastic work. Thank you for coming on the show once again; it's always a pleasure.
Thanks for inviting me!
If you enjoyed that conversation, then I think you are really going to enjoy this one that I've picked out. Especially the food you eat can either be the safest and most powerful form of medicine or the slowest form of poison. That's a phrase from Ann Wigmore, and I think it absolutely stands true.