The 5 best foods to fight cancer growth and lower your risk of death with Dr .William Li

You have around 10,000 cancer cells in your body right now, but most never become dangerous.

The science suggests cancer risk is not just about genetics, but how your body responds to these cells. So what can you do, day to day, to support your body’s natural defences?

Dr Li shares simple guidance on eating patterns that support your body’s defences, including increasing plant-rich foods and reducing ultra-processed foods. He also highlights everyday habits like staying active, supporting gut health, and limiting toxin exposure as ways to help tip the balance in your favour.

If your body is already managing cancer cells every day, what small changes could help it do that job better?

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Jonathan: William, thank you so much for joining me today.

William: Always a pleasure to be here.

Jonathan: And it is wonderful to have you back. I think you're the first guest we've ever had come back three times, so that tells you that we've really enjoyed our previous conversations. And it also means I don't really need to tell you what we do on the podcast. You will probably remember that we like to start with this quick fire round.

William: Bring it on.

Jonathan: Do almost all of our listeners have microscopic tumors in their bodies?

William: Yes.

Jonathan: Is cancer inevitable as we age?

William: Yes.

Jonathan: Are our genetics the main thing that determines if we'll get cancer?

William: No.

Jonathan: Can supporting our gut microbiome help reduce our risk of cancer?

William: Yes.

Jonathan: Should someone living with cancer cut out all sugar?

William: No.

Jonathan: And finally, what one thing do you wish people knew about the links between food and cancer?

William: Food can prevent cancer, period.

Jonathan: Cancer is a condition that we've all heard of, and I think almost all of us have either experienced it or have a loved one who has, it's very real. It's a word that immediately strikes fear into people and for very good reason. So I definitely want to talk about food as we get into the show, but actually I'd like to start by just understanding a bit more about what cancer actually is. And I'm really struck by your answer to this first question, this idea that almost all of us sort of have this microscopic tumor. So what is cancer and how does it start?

William: Well listen, cancer is the one condition, the C word that everybody is familiar with. Usually associated with dread, and everybody thinks they know something about it because we've all been touched by it. Someone in our family or friends. It's an abnormal growth in your body. It can be harmless or it can become very malignant and it can spread, and the treatment sometimes is more damaging than the disease itself. But nonetheless, when one is diagnosed with cancer, it seems like it's a death sentence for virtually everyone to date. All that is changing, and I think that this change comes about by understanding what cancer is. From the modern perspective, cancer is a normal cell that's gone wild. So if you think about young college students who are normally well-behaved and then they go on a spring break to a tropical island and they have a little too much to drink and they get together and they cause a ruckus, that's what cancer actually is in our body. And what causes that ruckus? Well, we have long known that mutations at the genetic level, problems with the DNA lead a cell that would just follow instructions normally, okay, to suddenly not follow instructions and begin to behave in ways that are errant and unrestrained, unchecked, just like the spring break analogy. Okay. Now, the idea is that if you have one or two people who are misbehaved in a crowd of normal people, that would be one or two individual cancer cells, microscopic cancers, and a sea of normal cells. You know, that's not so bad. You can usually spot the problems and take care of them and ask them to kind of calm down, or excuse themselves in the room. And in fact, that's what our human body does. We are composed of this enormous collection of cells, about 40 trillion cells in the human body. And each of these cells have to replicate themselves. So we have to copy paste ourselves. That's why we're still here from yesterday. That's why we're still gonna be here tomorrow. Now, in copying, pasting ourselves, just like a word processing document, we can make mistakes and because, and when a cell copies itself, it's gotta copy the DNA genetics. When you make a mistake in copying copy paste on a cellular level, that's when you can actually cause a mutation. So, interesting statistics, right? First of all, I want to just lay it out for anybody listening or watching how easy it is to make a mistake when you copy and paste, right? So, Jonathan, if I gave you, Mary had a little lamb as a sentence and I asked you to type it 10 times, you'll get it perfectly. If I asked you to copy it a hundred times, you might make one or two typos. Now, good news is that the word processing program will have a spell check. It'll catch it and it'll fix it.

Jonathan: Yeah.

William: Maybe even before you're done. Okay, but if I asked you, as the human body does to copy that sentence 40 trillion times, I guarantee you you're not gonna catch all the mistakes. That is exactly how microscopic cancers normally form in our bodies as a matter of course.

Jonathan: We have so many cells in our body and they're constantly having to like, replicate, make copies of the cells. It's sort of inevitable that it's gonna go wrong from time to time.

William: That's right. And that's okay because an errant cell sitting here or there as a microscopic abnormality, let's call it a microscopic cancer, just sits there. And guess what? It can't really grow because on its own, in order for a small individual abnormal cell to turn into a tumor, into a large deadly cancer, certain things need to happen. All right? And our body is well equipped to find these microscopic cancers. So I just want to give you an interesting statistic. So those 40 trillion cells that are copy and pasting every single day are faced with a pretty formidable body spell checker to catch all the mistakes. Nonetheless, some of them escape and are not detected. Do you know every 24 hours, how many mistakes of DNA copying escape our spellchecker and reside as resultant microscopic cancers every 24 hours?

Jonathan: Five.

William: 10,000.

Jonathan: 10,000.

William: Every day, every 24 hours, our copy paste mechanisms leaves 10,000 genetic mistakes that are microscopic cancer. So when, you know, we talk about like, do you have cancer right now? We all have cancer right now because this is basically how we copy ourselves. There's some little microscopic mistakes that are left over. Will they become deadly? Most of them not. Why? Because even though those 10,000 microscopic cancers are lurking somewhere in our tissues and they're not dangerous. And one of the reasons they're not dangerous is our body has this formidable ability to prevent abnormal blood vessels from growing to feed cancer cells. So this is part of what I study. Angiogenesis, angio blood, blood vessel, how our body defends its health by protecting blood vessels to go where they need to go. But to prevent them from going where they should not be going. In this case, our body prevents blood vessels from feeding cancer cells naturally. Our natural anti-angiogenic defense system. It's a shield to prevent cancer cells, those mistakes, 10,000 mistakes every day from actually being able to suck up oxygen, grow selfishly, get nutrients, and take off like bad guys. Alright. Second thing that our body shields itself from deadly cancer growth. 10,000 mistakes every 24 hours sitting around as microscopic cancers. Fortunately, we have this remarkable immune system that essentially acts as an army of super soldiers that patrol the body. They are in our bloodstream. They go into our tissues, they fly around with the radars on looking for anything abnormal. They recognize normal as self. Leave our cells alone, but they recognize abnormal mutations, those 10,000 mistakes as problems. So then they will zero in right on those abnormal cells, mutated cells, and take them out. So think about this, think about a peaceful neighborhood, which would be our human body, and you've got policemen, cops on a beat doing a routine cruise just to make sure the neighborhood is safe. Everything looks pretty decent, but all of a sudden, on a corner, you see this scraggly individual who looks like a drug dealer. It may not be actually dealing drugs at the time, but really looks unsavory. So the squad car, the immune car pulls over and decides to pick up this errant individual, stick them in the back of the police car and cart them off. And that's exactly what our immune system does whenever it spots one of these errant cells. So this is really the new dynamic of cancer. Cancer is us. It's very much part of who we are every day. Most cancer cells that do appear inevitably are harmless because we have our own defenses. And when our shields are up, we are particularly well armed to prevent cancer from becoming dangerous. When our shields are down, okay, suddenly the odds are tipped to put us at greater risk.

Jonathan: I'm really struck by how dynamic this picture is that you're talking about, William, that rather than, you know, we're healthy for years and years and then there's this one-off thing that goes wrong and it starts to become a cancer. You're describing this incredibly active situation where you're saying like there's 10,000 like individual cells that are going wrong every day and that my immune system though is sort of scanning me all the time and it's basically catching these 10,000. So this is definitely, it's a police state we're talking about if thinking about your police example here, it's a tough neighborhood in my body. I'm also struck by the analogy maybe that, you know, we all lived through COVID and we suddenly got used to this idea that a virus has a particular shape on the outside. And you know, our immune system recognizes that and learns to say like this is wrong and gets rid of it. But if it's never seen the virus before, like we had with COVID, like a lot of people got very sick or died because it was new. And is that an analogy here that somehow you talked about recognizing our own, that it can actually already tell with these microscopic single cancer cells, there's something wrong on the outside that distinguishes these cells from like all the trillions of other cells you talked about?

William: Yeah, I mean, listen, I'm a cancer researcher, that's my background. So I can tell you, having seen this with my own eyes, if you take a normal cell, human cell, you pick your organ. You mutate it and then you look at that same cell under the microscope. Okay? In a separate glass dish, you can see the behavior is different. The cell even looks different. Optically it looks different, and the behavior is very different. And these differences are what the immune system is picking up. And the reason I'm actually building this case of a dynamic ecosystem of defense against cancer is not just to try to recast cancer as a disease that makes us victims, but really it's part of our own defenses. This is actually quite empowering because we know that if we expose ourselves to forces that stoke more cancers to develop, more mutations, more inflammation. By the way, these little microscopic cancer cells, they love inflammation. It's kind of like pouring gasoline onto the embers of a fire. If you put inflammation around these guys, they love to start growing faster. Everyone has talked about wanna lower inflammation, wanna have a better gut microbiome, we want actually anti-inflammatory foods. Hey, this is the very reason why lowering inflammation actually decreases your risk of cancer very fundamentally. You wanna tip the odds in your favor, you wanna lower inflammation.

Jonathan: I wanna know what happens next when this doesn't work. So you were describing like in theory, I kill all 10,000 of these every day and they're all gone. But sometimes obviously that doesn't work because sometimes we do end up getting this cancer tumor and you described, you know, the fear and the worry. What happens that means that sometimes my body doesn't manage to deal with this when it's just one cell.

William: Let's nail this right now. When cancers take off and become deadly, it's really because our health defenses, the very things that are designed to protect us against these growths, actually fail us. They're weakened or they're absent. So if your immune system goes down, guess what? The police can't sweep up the bad guys anymore. If you've got a lot of inflammation lit up. Not small inflammation, but chronic inflammation. Wow. All of a sudden now you've lit a wildfire to spark the cancers from growing. If you trip up the body's ability to prevent blood vessels from growing and feeding the cancer, well now the cancers are gonna be fed. You're giving them oxygen and nutrients. And so this idea that these little single, individual abnormal cells don't exist alone, but they exist in a micro environment, other cell types. Other tissue matrix, they live in a kind of a cocoon, let's say, of normal cells and cell parts. And what's happening around those cell parts makes a big difference. You know, anything you do to normal tissue that can stoke inflammation, that could decrease immunity, that could cause more blood vessels to grow. By the way, inflammation and blood vessel growth, they go side by side. They occur together so the inflammation can trigger new blood vessels to grow into a tumor, which can be really, really dangerous.

Jonathan: I think you're saying that one thing that's gonna lead this is if it's somehow my immune system is like compromised or weakened, then that's clearly a big risk. Which makes sense because you're saying that's the thing that's going around. So if there's something wrong with the immune system, I guess I can see how it will escape. You also have mentioned this thing about inflammation being higher as a risk factor. Could you help me to understand what you mean by that? And why does that like allow some of these cells somehow to escape the careful checking that my immune system is doing?

William: Right. So think about these individual microscopic cancers as seeds. They're not good seeds. They're bad seeds, okay? And they're sitting in soil. So the seed in the soil patch, its idea of cancer living in its own fertile soil. And what happens around the soil can affect the growth of the seed. So inflammation is basically feeding the seed. It's watering and fertilizing the seed, the bad seed in a way that allows it to begin sprouting roots, establishing itself and growing into what you don't want it to grow into. Now remember, inflammation is actually normal and healthy, so it's the chronic inflammation that's actually stoking the growth. What does it do to the seed? Why does inflammation do that? Alright, so this seed is always trying to establish itself by releasing its own fertilizer. They call them growth factors. They're peptides and proteins. And you know, right now in the whole biohacker longevity space, there's like a big enthusiasm about peptides. Well, I can tell you because I study peptides, growth factors, they're hormones and they're signals that one cell produces that triggers a cellular signal with another cell to tell the other cell to do something. And so two cancers also release these growth factors at a low level. You put inflammation around that seed, that bad seed, and suddenly the inflammation enables the microscopic cancer to produce more growth factors. And in fact, indeed the inflammatory cells that will start to gather around, kind of like hover around this little tiny dormant cancer. Once harmless, the inflammatory cells themselves will dump more cytokines. Growth factors. Now we remember cytokines from the COVID era. They cause inflammation. They cause all kinds of stress reactions. Now you're dumping this around the cancer. Alright? Your normal cells don't like it. They're like, you know what? This is not comfortable for me. But the cancer's like, bring it on baby. I wanna get these growth factors. Thank you for the fertilizer. Now it's time for me to take off.

Jonathan: Most of us listening know that like chronic inflammation isn't good. 'Cause I mean, it just sounds bad, but could you help us understand a bit more what it means to this idea of it sort of feeding these cancer cells and setting off this chain?

William: Well let's talk about situations that we all encounter that we might be familiar with. We all have been out, hopefully, to enjoy beautiful weather under the sun. You get a sunburn, you get inflammation. We know the skin gets red. Blisters. It's terrible. That's inflammation. You do that over and over and over again. That radiation from the sun is mutating the cells, you keep on burning yourself, you're setting out inflammation. That's how a small microscopic, abnormal skin cell that turns cancerous can suddenly become a melanoma or a non-melanoma skin cancer. So that's an example of where normal goes to abnormal, non-inflamed goes to inflamed and boom, it's like pulling a trigger to force it, to stoke it to go into cancer. Let's give another couple of examples that people might understand, you know. People who drink a lot of alcohol can have acid reflux. Alcohol can relax the sphincter at the end of our esophagus relaxing the opening to the stomach. And the stomach acid can splash up and you can wind up having esophagus burns. Alright? Esophagitis is what we call it. It's a severe form of heartburn. Once in a while, you know, if we have it, we all have heartburn every now and then. Not a big deal. You drink a lot of alcohol and you wind up having a lot of heartburn over time. You wind up having chronic inflammation in your esophagus. And because the stomach acid can cause an injury and damage and cause mutations, now you've got normal esophagus going to abnormal the splash. Now you've got non-inflamed to inflamed and that can trigger off the growth of an esophageal cancer or esophageal stomach cancer. Really deadly type of cancer.

Jonathan: So this is really almost like your analogy of like the sunburn, which I think we can all get our heads around. We know that, you know, if you get a lot of sunburns, right? You have pale skin like mine, then you could get cancer from the sun. You're saying these analogies. There's like this inflammation inside me is doing the same thing.

William: And then one more. What about smoking? Whether you're talking about vaping or you're talking about cigarettes, pipes, cigars, you're putting in toxins into our lungs, exposing these really fragile normal lung cells. Listen, all they wanted to do is exchange gas, oxygen, and carbon dioxide. All right? Now you're exposing these toxins. The toxins will cause DNA damage. All right? Good news is that we'll fix a lot of the DNA damage, we'll clean out some of those damaged cells. But you know that spellchecker isn't perfect and you have a few microscopic cancers in the lung. Now you keep on smoking, alright? And that lung, the toxins caused that lung to be quite inflamed. Now you've got a normal cell that became abnormal. You got non-inflamed lung tissue becomes inflamed tissue. And this is really that connection between smoking and lung cancer that can occur. So this paradigm, by the way, Jonathan, is something that we've known for decades as the trigger for cancer. And what's interesting is that a long time we were just stuck with this idea, well, we gotta kill the cancer cell. If the body can't do it well enough, we just gotta kill it. Right? And there's all this lexicon that comes from wartime, you know, the war against cancer. We've gotta bomb the cancer. Chemotherapy is a missile to go attack the cancer. Well, what's happening now with a much deeper understanding of our body's defense. And I think this is really in line with sort of the entire thesis of Zoe and what you guys have been working on all this time is how do we get the body to buttress its own functions so that it can actually heal itself, defend itself in the best way possible. And so what we're realizing, even though there's a microscopic cancer in a microenvironment that's influenced by inflammation, and that's, you know, kind of countered by some of these healthy defenses, the reality is, is that there's the rest of the body that is coming to play that we can amplify our own defenses as a counter against cancer. Now, you could do this with drugs and I've been involved with drug development. So some of the most remarkable advances in cancer treatment I've seen in my own career, like jaw dropping results that we could never have imagined before are happening now. But secondly, we're beginning to realize that same approach opens the door avenue for really pragmatic lifestyle, diet and lifestyle choices as well. And the gut microbiome plays a central role in all of this.

Jonathan: I'd love to switch now to the risk factors for cancer, and I know we're gonna talk a lot about food specifically. So just before we get to that, what are the other risk factors aside from diet, that are really going to influence what you've been talking about?

William: Almost everyone recognizes that there are genetic risk factors, right? Okay. Cancer screening, we can do that with blood tests, we can do that with biopsies. We can do that with a lot of different types of saliva. But all cancers, only 5 to 10% of cancers are genetically driven.

Jonathan: I am surprised by that because I think we hear so much about breast cancer and genes related to like much higher risks of breast cancer. I'm surprised.

William: 90 to 95% of cancers are attributable to environment, diet, and lifestyle. Only 5 to 10% are purely genetically driven. And what that means is that in fact the odds are really in our favor. You know, if you have a genetic risk, a family history of a particular genetic inheritable cancer, like breast cancer, ovarian cancer, you know, there's some very specific ones. Okay? What do you do with that information? Well, now you gotta double down to protect yourself, besides just availing yourself to the health system. Now, you should actually take steps to double down and improve your own health defenses. But let's say you don't have a genetic risk factor, and I'm gonna talk about other risk factors in a second. You should still use the majority of those factors largely under our control environment, diet, lifestyle exposures, what we eat, how we live, to be able to tilt the table in our own favor. But let's talk about some other risk factors as well. Genetics, minority risk factor important, but a minority. Number two. Smoking, drinking. You know, we talked just a little earlier about this idea that the toxins from tobacco and probably worse from vaping actually are a serious trigger for mutations that can turn normal cells into abnormal cells that then lead the way to becoming something dangerous.

Jonathan: And William, I think everyone is gonna be unsurprised that smoking causes cancer. I think you'd have to have lived under a rock for the last 70 years not to hear that, but I'm interested, you just mentioned vaping. Is there evidence that this is a risk for cancer?

William: Oh yeah. Vaping is definitely a cancer risk and it's been well established in the lab. It's being seen in the clinic and arguably the chemicals in these vaping solutions are even more irritating, even more toxic than traditional tobacco. They're different, but we think that they actually may be even more DNA mutating. And so, you know, for those people who like, well, vaping's a safer alternative, at least I'm not smoking, you know, you might be doing something even worse for yourself. I will also say even pipe smoking where you're not inhaling, you're just putting the smoke in your mouth. Or cigar smoking, which is not deep inhalation, that actually can be cancerous as well.

Jonathan: You also just mentioned drinking and I think people might be more surprised that you are talking about cancer with drinking. I think everybody knows that it's bad for you, but I'm not sure that that would've been high on most people's list.

William: Well, alcohol does a lot of things. Listen, I have a cultural respect for the importance of alcohol in the human society. We use it to celebrate events and to recognize major transitions in our life. But alcohol itself, the ethanol, the ETOH chemical is actually a pretty significant cellular toxin. There's no cell that alcohol spares and in contact alcohol pretty much preserves it embalms the cells that it touches. So we can drink it, we can process it. Our livers are generally pretty good. You know, who doesn't enjoy a nice beer or a good glass of wine every now and then? But you know, that's not the risk factor. The risk factor is the people who are drinking heavily. A six pack a night, they're drinking two bottles at a time. They're drinking even heavier alcohol. It doesn't even taste great, but it actually gives you the full burn, right? The hard liquor. You do that occasionally, your head's gonna hurt the next day. You do that every single day. That toxin is causing that DNA damage and remember every 24 hours, you know, you're still just as a matter of copying, pasting, you're defending yourself against some leftover mutations. Now you're scorching the earth with this toxin and creating a lot of mutations. Now you've really tipped the odds against you. So that esophageal stomach cancer, alcohol related for sure. By the way, what's the organ that is our salvation against alcohol toxicities? It's our liver. Our liver, remarkably is this cleanup organ against the toxin of alcohol. Most of us actually have really good livers and can neutralize the effect of alcohol, but it can only do it up to a certain point if you overload your liver. It's gonna fail. And when it fails to detoxify, now you've got that toxin running amuck in all the tissues in your body, making every organ at risk for having more mutations. And so alcohol is a well known, like it's really heavy drinking is well known to be an elevated risk factor for many different types of cancer as well.

Jonathan: You know, if you've had too much to drink, it can be hard to get outta bed and it's definitely really hard to function effectively at work. I can only imagine that my immune system is also struggling to do quite as good a job as it might otherwise.

William: Alcohol stuns the immune system. It's basically like taking a blackjack and knocking it over the head.

Jonathan: Alright, well I don't think anyone listening to is surprised to hear it's not good for you. Are there any other important risk factors for cancer?

William: There is a growing category of risk factor that we are really paying attention to because they're environmental. Listen, smoking and drinking are lifestyle. What about environment? We are noticing in many Western countries, so you're talking about United States, North America, Europe, that cancers that were once diseases of older people, sixties and seventies, like colon cancer are now becoming cancers of younger people. Things that were once diagnosed when you were 60 or 70, and we're now seeing in people who are in their forties or thirties or even twenties or for colon cancer, there are even cases now of teenagers developing colon cancer. What the heck is going on? Is it our environment? Is it toxins we're being exposed to, you know, there is research under glyphosate and other pesticides. That's not the only one that, you know, we're wondering is it exposures in our food? What about microplastics? You know, we don't a hundred percent understand the full implications of accumulating microplastics in the air we breathe, the water we drink, and the food that we eat. Okay? But we do know that they can accumulate in our blood vessels, in our organs, we're finding microplastics in brain tissue. That's, you can actually measure it on a scale brain without microplastics versus brain with microplastics, you tip the scale like it's measurable. And I don't think we need to wait for our randomized placebo controlled double-blind trial to assume that having plastic in your body accumulated over years is not a good thing. I don't need that kind of evidence. You know? And I think this is important because there are suppositions that do require an overwhelming body of evidence to be able to make a meaningful action. But here I think we have to think about in real time, are there exposures like microplastics that are accumulating in the bodies of young people that are tricking the immune system, causing inflammation, creating mutations, could that be going on? And that's the stone we can't afford not to look under. So I think these environmental exposures are becoming really important.

More and more research is showing that the consumption of ultra processed foods is associated with a higher risk and a higher disease burden. So not just a theoretical risk, okay, projected risk or the overall risk, but actually the occurrence of more severe chronic diseases including cancer. What's the easiest cancer to look at association with what we eat? Colon cancer. 'Cause what we put on one side of our gut eventually winds up being processed in our bodies and sitting on the other end waiting to be eliminated in the toilet. And so the colon is sort of a storage tank of what's left over from our food. And if we have undigestible unmetabolized, highly processed preservatives, colorings, flavorings, sweeteners, it's sitting there by the way, intermixed with our healthy gut microbiome. For better or worse, usually worse. Now we're actually affecting another health defense system, our gut microbiome, and you're exposing those cells in your colon to all these toxins. And so many of these ultra processed foods, artificial preservatives, we're seeing that they're tied to the development of colon cancer. And by the way, it's not just ultra processed foods. There are categories, like processed meats that are considered by the World Health Organization as a class one carcinogen.

Jonathan: As a class one carcinogen.

William: Like smoking.

Jonathan: And what is a processed meat for people who might not know what exactly that means.

William: So I'm not talking about, you know, your grandmother's handmade hand ground sausage that she air dries in the cellar in Tuscany. All right, I'm really talking about pepperoni in your pizza. I'm talking about the deli meat that you go out and pick up a sandwich on or at the lunch line, or something you might buy at the supermarket, because it's easy and convenient. Do you know why it's called deli meat?

Jonathan: Tell me why you call it deli meat?

William: Because it was named after Delicious Meat. Okay. It was actually a brand created to buy up scraps of leftover food waste during the war, World War II, so as not to waste food to provide inexpensive food. And they pulled together all this scrapple, so to speak, wanted to brand it, to make it sound delicious. They call it deli meat. And by the way, these are all little scraps of protein from tails and bits and feet and all that kind of stuff, right? And so if you think about it growing up. Did you ever question ham bologna? What part of the animal, the pig, is perfectly round like that, that you can slice it and you get a circle, right? Like how do you get there? Well, that was part of the innovation of the food industry. They had to invent meat glue in order to be able to take the scraps that were ground up into a fine powder, glue it together, and then mold it into a shape that could be sliced. We all know that protein intake is important for health. We know that animal protein can actually be quite healthy as well, not only for the protein itself, but there are other micronutrients that are actually present in and people who do eat animal meat, which is fine. Now what's interesting is that when you take meat and you turn it into a product in a form that doesn't occur in nature, right, that's where you start to get into this processed meat.

Jonathan: And well, I think bacon is also an example of a processed meat. Is that right?

William: It is a cured meat with factory nitrites. And it turns out that when you take those chemicals, those factory nitrites and you expose the gut bacteria to it, you alter the gut microbiome and it can actually alter the behavior of what your healthy gut bacteria are trying to do as well. Is that the cause of the association of eating those nitrite rich processed meats with colon cancer? We're not a hundred percent sure, but likely contributory to the inflammation that can actually result as well.

Jonathan: So we don't know exactly why these processed meats are such a high risk for cancer, but potentially the microbiome is part of the story.

William: We think the microbiome's definitely part of the story. Think about the gut microbiome as just another one of your body's health defenses. Like I wrote about this in my book, Eat to Beat Disease. Your immune system is an incredible defense system for your body. As we discussed earlier, patrols your body, army of super soldiers looking for trouble and cleaning up the problem, your gut microbiome is another defense system that is hardwired into us. It is functioning to lower inflammation, help our metabolism, coax our immune system, groom our immune system, communicate with our brain. All the wonderful things that you guys know very well at Zoe and are leading the research on. So anything that we do to damage that gut microbiome damages our defenses. And in the setting of cancer, abnormal cells where, you know, we're already sort of on a knife edge, making sure that these mistakes that escape are caught and eliminated. If you tip that balance away from defense, well we're giving cancer the opportunity to take their own offense.

Jonathan: That's really interesting. I think one thing that we do know out of all the Zoe data from many of which is from participants who are listening to this podcast, is that we've identified a set of specific microbes, which you get if you're eating these sorts of processed meats that you tend not to see otherwise. So that doesn't, as I understand it, necessarily prove that they are the specific cause of the cancer. But there's definitely like correlations about specific bad bugs that really like this stuff.

William: And I wanna step in here just to talk a little about this correlation causation argument just for a second. In complex systems like biological systems, we can do better than simply ascribe a cause and effect because usually it's not one thing that leads to the other, but it's a constellation of forces that lead to the end result. And so I love the fact that you just described an observation from Zoe's studies looking at the gut microbiome that have identified some candidate bacteria that are associated with eating meats that's associated with higher risk of cancer. And I don't think we need to look for the causation. I think we get way too invested into cause and effect linearity off and on. Right or wrong. Good versus evil. I think what we really wanna be able to do is to say what are the forces that might ruin the neighborhood and can we try to restore the healthy neighborhood in a much better way. And I think that's why I do think even though processed meats is considered a class one carcinogen by World Health Organization, it doesn't mean that you should never eat processed meat. I think that if we try to take a more balanced view about life and realize that other foods that we might eat, you know, that would include plant-based foods, dietary fiber foods that actually nurture the gut microbiome, we can actually counter some of those negative forces. You know, life is for the living. As a cancer researcher, I could scare the bejesus outta myself of all the things I shouldn't do, but in fact, it actually empowers me to say, you know what, as long as I'm actually doing more good things than bad things, net net, I think I should be okay.

Jonathan: I definitely want to talk about some foods that could actually help to like fight getting cancer. And just before we do that, there were two others that I've sort of heard could be associated with increased cancer risk. And I just want to ask your perspective. One of them is like grilled meats, particularly on like the barbecue and the other one is sugary drinks, sodas. What is the evidence about either of those?

William: Let's take 'em one by one. Listen, grilling is one of the oldest human ways of cooking food. There's something uniquely human about eating grilled foods and it tastes great. I mean, who doesn't enjoy, you know, a delicious grilled meal or even vegetables. But the problem is that if you eat a lot of grilled meats continuously, what we know is that the fat that drips off the grilled meat that hits the flame, that then turns it into smoke and chemical forms, will accumulate on the meat, and those are toxins and there's multiple toxins that can accumulate on the meat. Then when you eat the meat, you're actually eating a toxin, right? Tastes great, not great for you. Once in a while, not a problem. And by the way, most people don't clean their grills. Well, you know, a restaurant, they clean it every night. But, you know, you go to your friend's house for the barbecue and you watch them grilling, and you look at this thick rind of soot that's accumulated over gosh knows how many parties in the backyard they've actually had, that's just all accumulated toxins that are there. So again, you know, even taking care of the grill makes a difference. And by the way, you can neutralize that to some extent. Some interesting research has been done showing if you were to marinate the meat with a fruit-based marinade, think mango, papaya, pineapple, citrus. You can actually neutralize some of those toxins. Create a cancer toxin neutralizing kind of marinade for the meat. So that's a little pro tip. I actually like to cook, so that's why I'm telling you about this.

Jonathan: I like that you add a plant to help deal with some of the stuff that comes from the meat. What about the sodas?

William: Alright, again, soda is sort of like everyone's favorite whipping boy. Rightfully so. The preponderance of clinical evidence, public health evidence shows that high consumption of soda is associated with everything from metabolic disease to cardiovascular disease to cancer risk. But is it the sugar? Is glucose, you know, that demonic element that, you know, we need to crucify? Answer's no. It is true that your average 12 ounce can of soda, you know, and at least in America, I saw, by the way, I saw an Instagram post recently of a British woman who's comparing soda in the UK, which is the same soda in the US and reading the amount of sugar and like it's a completely different order of magnitude. The color was different, the dyes were different, and the amount of sugar was different. No doubt about it. You know, excess carbs in the form of glucose or fructose, whatever's in the soda actually is overwhelming to our healthy metabolism. Is it cancer causing by itself? No. Zero. Does it actually tell us that the sugar feeds cancer? So you should, any cancer patient should avoid sugar. Anybody wants to avoid cancer, should cut sugar. No. That is also an urban legend. Okay, so what I would tell you is that soda is not just water, otherwise that'd be just carbonated water. But soda itself has all these additives, colors, flavorings, preservatives, stabilizers together at the volume in which soda is consumed in many parts of the world. That is that accumulated exposure to toxins. Remember we talked about environment, diet, lifestyle, and it's not one exposure, it's the chronic exposure over time, and that then becomes a behavioral issue.

Jonathan: I'd love now to talk about what we can add in and you talk about this, you know, in your book, I know that you think like a general healthy pattern of diet, of a sort we talk about a lot here is really good for this. I'd actually love to speak about a few specific foods.

William: Okay. So soy, great source of dietary protein, plant-based food, got dietary fiber in it. And it's got bioactives that are isoflavones, of which one of those isoflavones, phytochemicals actually is a plant-based phytoestrogen and well-intentioned people who once heard that some forms of human breast cancer are sensitive to human estrogen naturally made the connection that maybe soy would be harmful to eat because it's got a phytoestrogen, but if you're a researcher like me and you know something about chemistry and you were to call up onto a screen or a book, or do a Google search and look for human estrogen and look at phytoestrogen, just even look at the chemical structures, they look nothing alike. And in fact, what is true is that plant estrogens, phytoestrogens from soy don't actually mimic human estrogen. It blocks human estrogen. It's kind of mother nature's tamoxifen, which was a drug designed to block human estrogen. So the real question is whether or not soy is a good cancer fighter. Yes, it blocks human estrogen for estrogen responsive cancers, number one. Number two, these phytoestrogens, one of 'em is called genistein. I've done research on this. Potently starves cancer by cutting off the blood supply. So now you're boosting your body's own ability to starve a cancer so it can't grow. Now, if you're a skeptic, you might say, prove it to me. I know no woman is gonna wanna eat tofu or drink soy milk, just on an anecdote. Well, how about this? A study called the Shanghai Breast Cancer Study looked at 5,000 women who are at the highest risk for breast cancer. Why? Because they already have breast cancer. Super high risk. Okay. Yeah. And they found that those women who consumed the most soy, about a cup of soy milk a day, 10 grams of soy protein a day had a 30% decreased risk of dying of their breast cancer. That's mortality.

Jonathan: 30% lower chance of dying of breast cancer if they were having lots of this soy.

William: That's correct. So the complete opposite of the fear factor is the empowerment factor. This actually lowers death now for those women who already had their breast cancer successfully treated and don't want it to come back. There were some women in this study who had that. Those women who had more soy also had a 20 to 30% less chance of having their cancer recur. That's secondary prevention.

Jonathan: And if I'm a man listening to this, is this like irrelevant or even worse? 'Cause you've mentioned that word estrogen and I'm worried I don't wanna have any of that.

William: Well, the anti-angiogenic cancer starving effects of soy are beneficial to both men and women. Social media is filled with skeptics out there. They're like, well, you just cherry pick this one study. What about the study? Well, I could name 14 consecutive studies looking at soy intake and breast cancer. And in every single case, higher consumption of soy did not increase mortality. Rather, higher consumption of soy decreased mortality, decreased the risk of death. 14 consecutive studies.

Jonathan: I love it. What's number two?

William: Tomatoes are an incredible source of an anti-inflammatory bioactive, vitamin C, great for hydration. They are packed with carotenoids that are very important and useful for healthy aging, healthy vision. And one of those carotenoids, a natural compound called lycopene, has been studied and it has a powerful cancer starving effect. This was studied in men, so earlier we talked about women and soy. Let's talk about men and tomatoes. There was the Harvard study called the Health Professionals Follow-Up Study. Looked at 36,000 plus men over two decades. I'm talking about a long study, and they looked as in these large studies for consumption of specific foods and to see about any association with particular diseases, what we've known for years is that lycopene can cut off the blood supply feeding cancer. And so they looked at lycopene intake and prostate cancer and found that those men in this study who had two to three servings of cooked tomatoes per week had a 30% decreased risk of developing prostate cancer. And don't forget the vitamin C antioxidant lowers inflammation, all beneficial as well. Now, the other thing that's interesting is if only 30% lower risk, some people did develop prostate cancer, they dug into those people as well. Those people who ate more cooked tomatoes and had prostate cancer had less aggressive, less vascularized, less blood vessel fed cancers. So it's a pretty tight connection between eating tomatoes and a lower risk of prostate cancer. You wanna make the tomato work better, you combine it with extra virgin olive oil because lycopene dissolves in oil. And so that's why when you actually slow simmer a tomato sauce, you wind up getting more lycopene into your bloodstream.

Jonathan: Is that right? So the Italians know what they're about.

William: They absolutely knew what they were about.

Jonathan: I love that. What's number three?

William: Apple a day, supposed to keep the doctor away. Turns out that there is a potent bioactive polyphenol in apples called chlorogenic acid. It is a super potent anti-inflammatory substance found in the flesh of apples that when we eat it, really helps to lower our inflammatory biomarkers. And the fiber in apple feeds our gut microbiome, which then produces the short chain fatty acids that further lower inflammation.

Jonathan: Amazing. So that's three down. I'd like to come on to number four.

William: I love berries, right? So berries, not one food. It's really a diverse bandolier of foods. Blackberries, blueberries, raspberries, strawberries, all of them are colorful. And the color, the common denominator, natural dyes are anthocyanins in many of the berries, including lingonberries. And all these gooseberries and anthocyanins tame blood vessels to make them healthier. 'Cause they're good for cardiovascular, but they also cut off the blood supply to cancers. They're also incredible antioxidants to protect DNA from damage. And also there is fiber in berries, like most people don't know this, but raspberries. Which, you know, you get a handful of raspberries, you wash them off, they're hollow. They almost float, almost lightweight, like airy. They are pound for pound, the most fiber rich berry food out there, and it feeds the gut microbiome, which then lowers inflammation.

Jonathan: If we were to do a study on almost any plant, would we discover that it's likely to have these sort of cancer fighting properties? If it's a plant that we know, you know, has fiber, has polyphenols, things like this?

William: You know, it's not the food fighting the cancer. I want to clarify that. It's what we put into our body that prompts our body to rear up and fortify its health defenses. And our body is the best cancer fighter. And so, you know, while we're under the throes and fear of chemotherapy and sort of the drugs of yesteryear for cancer. The great news that I want everyone to know is that the state-of-the-art cancer therapies are waking up our body's own health defenses through immunoactivation, immunotherapy. And this is where we're actually seeing the impossible become possible. We're seeing people who would've never had a chance of surviving their stage four cancer, actually having their body's defenses rear up, the defense immune system, alright? To be able to actually tackle, put the cops on the beat to tackle all those runaway cancer cells and to actually clean up the neighborhood again. This is the sea change that's actually happening now. You know, it used to be you didn't think about cancer until you wound up having to go into the doctor because you felt sick or felt pain, and then you gave yourself into chemotherapy or whatever the medical system had to offer. Now we're realizing that, you know, we are our own best defense against cancer. We don't know everything about how we defend against cancer, but we know a lot more than we did before. And the choices that we make, the environment we expose ourselves to, limit toxic exposures, the lifestyle choices we make towards more healthy choices and the dietary factors that we have. Not about eliminating everything that brings us joy, but actually balancing it to make sure we have enough good stuff to help counter some of the bad stuff that we all inevitably encounter. That's really, I think, a healthier way to approach diet and cancer fighting.

Jonathan: Brilliant. I'd like to come to number five now.

William: Amazingly, coffee and tea, which are two of the three most popular drinks in the world. Water, coffee, and tea. I call it the Holy Trinity. Coffee and tea both contain polyphenols that actually amplify the body's cancer fighting responses. Tea has catechins. These are polyphenols that cut off the blood supply to cancers, lower inflammation. They boost the immune system and even the fiber found in tea leaves can feed the gut microbiome. Coffee has chlorogenic acid, the very same substance that actually is found in those apples, that lower inflammation, as well as many other compounds, right? So the reality that there are hundreds and thousands of molecules still to be discovered, and to me as a researcher, this is one of the most exciting things of being a leader in the area of food as medicine, is that we're just beginning to enter this new era where almost every day there's a new discovery being made.

Jonathan: And I'm a very keen tea drinker, as everybody who knows me will say. Is there a particular sort of tea that is healthiest?

William: We've looked at comparative potency of teas, but if you want the full strength of cancer fighting, health defense activating ability, go for matcha, because matcha are potent tea leaves, green tea leaves, and you get the entire thing, you get all the fiber from that leaf itself, and that's what's actually gonna help your gut microbiome as well. I know we've touched on it, but I wanna underscore this. The microbiome is the undiscovered country for cancer prevention. It may turn out that many of the cancers that we wind up dealing with have their origin of escape from our defenses in something that we were not tending to in our gut. And it could have been from childhood, could be in young adulthood, it could be in older age, and fixing that by repairing the gut microbiome might be a new approach to cancer treatment that is completely untapped. That could be painless. I mean, I myself have taken part in helping to administer a fecal microbiome transplant in a cancer patient. And I can tell you it's remarkable to think we're not hanging a bag of chemicals and infusing it into a vein, but rather we're fortifying the gut microbiome. So exciting times lie ahead, promising times lie ahead. But everybody can do something today to tip the odds in their own favor against cancer.

Jonathan: If someone listening to this is feeling maybe a bit overwhelmed or that we focused on some specific examples, and maybe they're struggling a bit to understand what to apply, and you were gonna say, you know, if there's one sort of simple piece of advice about changing your sort of overall dietary pattern in order to help you to fight cancer in the future, what would be your sort of rules of thumb that you would be saying?

William: Eat more Mediterranean or Asian. Eat less American or ultra processed. That's one. Number two, drink more coffee and tea as your beverage and drink less soda. Alright, number three. What I would say is it's not, this is not just only diet, but stay active and exercise. You don't need a trainer, but you wanna stay active every single day. That activity, movement. Movement actually grooms our health defenses, our immune system, our gut microbiome, lowers inflammation. That's a really important thing. Number three, I would say number four, try to avoid toxins whenever possible. You know, we do live at a time of convenience culture. Most of us grew up with our parents being the pioneers of convenience culture, you know, the recipients of that industrialization of convenience. And I think that, you know, there is an enlightenment, I think, in the zeitgeist that we probably should try to avoid things that are harmful exposures. Even if it's more convenient, it's worth it to take a little more time to make a safer choice. And I think in that regard, what I would suggest is try to avoid microplastics, try to avoid food in plastics. Try to avoid eating or drinking out of plastic whenever you possibly can. And think about it when you're traveling. Which we all do, you know, and you should hydrate yourself. Try not to drink water out of that plastic bottle.

Jonathan: Wonderful. Let me try and do a summary of the highlights if you like. The first thing that springs to mind is this amazing statement that there are 10,000 new microscopic cancer cells in my body every day. But I shouldn't panic because actually my immune system is constantly scanning and it's like killing 10,000 of them every day. And that's just normal. So this is like a dynamic process. And the cancer is in that very rare situation where somehow that cell has managed to run away without my own immune system catching it. And so now we suddenly think about fighting cancer is above all, how do we support our immune system to do a better job? And how do we try and take away the things in our environment, you know, what we're eating, all the rest of it that might be somehow hindering the job that our immune system is doing. And you were talking about like this high levels of inflammation, which most of us in the western world have is like a big accelerant for these cancer cells. So if we can, you know, do the things that we often talk about here about like improving your gut microbiome to like reduce your overall inflammation, that's not just helping with things that we often talk about to do with metabolic health or maybe reducing the risk of Alzheimer's or things like this, but actually it can really affect cancer as well. So I think that's, that's really remarkable. You then talked a bit about what the risk factors were, and I was really stunned that you said that genes are actually only like sort of five to 10% of the risk. And so this idea we have that maybe it's hugely down to these risk factor genes for most people won't be true. Obviously very true for people with those specific genes. You covered the stuff that sounds important that we've heard about before about smoking. You talked about drinking alcohol heavily being a big risk, but then we really talked about food and you said yes, there are specific foods and classes of foods that are associated with a higher risk of cancer and we should worry about. Interestingly, you started with ultra processed food. You talked a lot about processed meats, and that was sausages and bacon and pepperoni and deli meat. Grilled meat. Don't worry about it occasionally, but you know, it sounds like you wouldn't want to eat grilled meat every day. And I guess our ancestors who were doing this all the time tended to get eaten by a lion by the time they're 30. So I could see that like whether or not you get cancer at 60 is very low on the list. And then what you did say is, look, there are all of these amazing plants that you can eat to fight cancer. And you know, today we just cherry picked a few out of your book because I think each was such a fascinating story. So it's not to suggest that there's just five, but you know, the one that I am remembering is, you know, the soybeans. You said there are these like big studies of women with breast cancer and the ones who are eating lots of soybeans, like I think they reduced by 30%, you said their chance of dying from breast cancer. And it's the complete reverse of what people were saying, which is, well, isn't this bad? We talked about tomatoes and apples and berries. But then the last thing, which was music to my soul is tea could also be helping to fight cancer. And if I want to go for the mother lode there, like it's time to switch to matcha 'cause it's got the whole tea leaf inside.

William: Well summarized.