What Silent Diet Factor Grows Cancer? Genes vs Lifestyle for Cancer Risk | CLIP | Vital Signs

On the back of the Human Genome Project, which set to map the entire human genetic code, came the Cancer Genome Atlas. Launched in 2006, it sought to catalogue the gene alterations that underlie cancer. Some 20 years on, it stands as a symbol of a tremendous and expensive genetic war on cancer. A war that we still don't look much closer to winning. Author of the Cancer Code, As it were, over this period of targeting cancer genetics, cancer somewhere actually overtook heart disease as the leading cause of death for those between 45 and 64. That said, where an over-focus on nature, that is the genetics, may have let us down, a renewed focus on nurture, that is our environment, is opening up hope. Today, Dr. Fung highlights the factors we can influence to bring down cancer risk. Diet being an obvious example, with obesity now linked to as many as 18 different cancers. Dr. Fung is a physician and a nephrologist, a specialist in kidney health. He's also the author of number one bestseller, The Obesity Code. What is the link between obesity, diabetes, and cancer? How important are the BRCA genes to breast cancer prevention and treatment? And where the seed of cancer is embedded in our genes, how do we change the soil to prevent it growing? Welcome to Vital Signs, where we learn how to get healthier from all angles, from the biochemical and nutritional to the things we do that nourish our minds and our souls. I'm Brendan Fowler. Dr. Fung, great to have you join us on Vital Signs again. Thanks for having me here. I know you've pointed out in your writing that the considerable, the billions of dollars that have been spent in cancer research and development over recent decades, particularly on the genetic side. We're going to look at that today in part. I'd just like to start though, in general, where would you say we stand at this point in time in terms of our ability to prevent and treat cancer? I think we're sort of on this, just at the beginning of understanding cancer in a whole different way. Because if you don't understand what a disease is, then you can't come up with really very logical treatments. So if you understand diseases are caused by bacteria, for example, which was a big breakthrough, then you say, okay, how do I kill these bacteria that are causing the disease and get antibiotics, which is a sort of massive breakthrough. So the idea is that cancer is not like any other disease that we know of. It's not purely a genetic disease. And in the last 10 years, there's actually been really very few immunotherapies been the one that really had the most impact. A lot of these gene therapies that really have had minimal or no impact on that disease, because that paradigm on which they're based, which is let's change the genes, doesn't really work. But this paradigm of, oh, let's treat cancer as this sort of, you know, speciation event or infectious disease. And let's see what we can do about it, that is a much more promising avenue to go, because it gets to the heart of what that cancer is. So even if you have the same gene, can you affect the environment, the soil that it's sort of living in? So you can't just say cancer is bad luck, you have to say, well, what is it in our environment that is feeding, that is leading, that is fertile soil for this cancer seed? And so stopping smoking was a very important thing. But it turns out that the second most important thing, so if you look at the things that cause cancer, you can, you know, do these big studies, and you can attribute risk. And the most important thing is really smoking. But the second thing was actually diet and obesity. By far and away was those two factors were about 30% of cancers compared to, you know, like two or 3% for everything else. And that's all the other things we think about chemicals and herbicides and pesticides and radon gas and asbestos and all these other things that we think about as carcinogens, actually paled in comparison to I did understand that the diet and obesity were factors in influencing cancer, but I didn't realize how high it was in the hierarchy. You know, breast cancer is one of the obesity associated cancers. So as you have more obesity, then the risk of cancer can go up. So if you have that original gene that puts you at higher risk, now, can you go backwards? Can you now affect people so that you don't always have to cut off the breast or, you know, take out the prostate or whatever it is? Can you affect it? And part of it is because insulin is, you know, people who are overweight or obese, they have high insulin levels, for example, that's that's part of the disease, and the high insulin levels acts as a growth factor to a lot of these cells. So if you can then change the diet or change their you know, weight, which we can, then can you change that risk so that it's lower than before, right? And that's the, you know, and you can't, we don't have all the answers right now, right? But perhaps we'll be able to do something more specifically in the future. Interesting to hear insulin mentioned there, Dr. Fung, because many people would think insulin and just think of it as something that's used to manage their type 2 diabetes. So it's a revelation to know that it actually works as a kind of growth hormone and can trigger tumor growth. How does that work exactly? And could you elaborate on that? And what is the solution to dealing with that? So insulin is a normal hormone, and we all think of it as a hormone that's important for metabolism. That is, you know, if your blood sugar is high, you take insulin, it goes down. But insulin is actually a growth hormone as well. And the reason that they're linked is that your body really only wants to grow when nutrients are available. So the way our body has sort of linked it to is that when you eat, insulin goes up and insulin then acts as a growth factor. So if you give people insulin, they tend to grow. So for example, if you give mothers insulin, their babies tend to be very, very big, because you're giving them not just something to control their sugars, you're actually giving them a growth hormone, if you will. So the idea is that if you have a disease where things are growing too much, well, giving them insulin is like giving them fertilizer, right? It's going to speed up that growth. So it's not the only factor that's at play, of course, but it is one factor that is relatively important. And it's chronic damage. If you have any chronic damage to a cell, chronic long standing damage, you need to get rid of it. And anything that causes chronic damage to cells can actually cause cancer. You actually see it even with chemotherapy and radiation. So even the very things that you use to cure cancer, actually cause cancer. So the initiating event is this event of chronic sort of damage that's happening chronic inflammation, for example, that's happening. And then the thing that's going to promote it is this high insulin level. So people who are overweight, have high insulin levels, people who have type two diabetes have high insulin levels sort of on a chronic basis, it has to be on a chronic basis for many, many years. And this is this is what's what's happened, you see with type two diabetes, that there's a strong association between that and certain types of cancer. In fact, it's very clear that diabetics have a much higher risk of cancer. So then what can you do about it, well, you can adjust your diet. So if you adjust your diet, you know, then you're going to have lower insulin levels, for example. So if you change your diet so that you're not eating foods that stimulate a lot of insulin, and you lose weight, then you're going to affect your risk of cancer because you're providing a less fertile soil for that cancer. It's not going to, it's not like one of these, you know, 100% you're not going to get cancer thing, but it's going to play a role.