A widely published medical researcher (and TED Talk rock star), Dr. Li has served on the medical faculties of Harvard, Dartmouth, and at Tufts universities. He is a disciple of the late Judah Folkman, MD, a groundbreaking cancer researcher who identified the process by which cancerous tumors attract blood vessels to themselves in order to nourish their own growth. Li is currently the head of the Angiogenesis Foundation in Cambridge, Massachusetts, investigating angiogenesis as the common denominator in many deadly diseases. “I’m a big believer in modern medicines,” he says. “But what I know from my own work is that food is the missing tool in the toolbox of doctors, and it’s the one thing that patients can do for themselves between doctor or hospital visits. So this is food as medicine and food with medicine.” Here he explains how he’s reframed the basic definition of health to better understand what food can do and tells why we all might consider eating more dark chocolate, sourdough bread, and kiwi. Everyday Health (EH): Most doctors seem quicker to prescribe drugs than to tell patients what to eat. How did you come to focus on the power of food? Dr. Li: As a medical doctor, I’ve spent the past 20 years doing what I was trained to do, which is diagnosing [life threatening] diseases after the horse has left the barn, then writing prescriptions. But about 10 years ago, the light bulb went off in my head that there was something much bigger and better that not only we could do but that we should do, which is to prevent disease in the first place. And that’s what led me to go back to ask this question: What is health? If health is not simply the absence of disease, what is it the result of? The answer is this: Our good health is the result of our body’s hardwired defense systems that are protecting us from the day we’re born until our very last breath. EH: You identify five of those core health-defense systems in the book. Can you run through them for us? Dr. Li: You’ve got one that’s called angiogenesis — just a fancy word to describe how our body grows and maintains 60,000 miles worth of blood vessels, delivering oxygen and nutrients to every cell. You need to balance them so there’s not too few and not too many, and foods can activate that. Another defense system is stem cells. Humans can regenerate tissue, and we do it from our stem cells, which regenerate our organs even as we age. Then there’s the microbiome, an ecosystem of 39 trillion bacteria in our bodies that communicate with our immune system, helping us fight all kinds of nasty health conditions. Our DNA is a fourth health-defense system. Our environment is filled with dangers to our DNA — ultraviolet radiation from the sun, secondhand smoke, off-gassing from the carpet. But our DNA is remarkably hardwired to neutralize incoming damaging signals, and it can repair itself. The fifth health-defense system is the immune system. We have always thought that, as we get older, our immune system weakens. But it turns out that, when given an opportunity to do its job, the immune system of somebody in their eighties or nineties is powerful enough to wipe out metastatic cancer. Food can activate and support all of these systems. RELATED: 5 Ways to Boost Your Immune System Over the Holidays (and Anytime) EH: This seems like a more scientific way of talking about food and health than most of us are used to. Li: Our health is incredibly complicated. It’s much more than just jogging, juicing, and yoga. The science has advanced enough for us to start thinking about not just what we should remove from our diets, but what we should or could add to strengthen ourselves. RELATED: Heart Health Benefits of Yoga EH: Can you talk about some specific foods that help cut off angiogenesis in cancerous tumors? Li: Soy. Cancer can hijack our blood-vessel system to feed itself. Tumors can’t grow bigger than about 2 millimeters in diameter, the size of the tip of a ballpoint pen, without a blood supply to deliver oxygen and nutrients. But lab research has shown that once blood vessels touch one of those tiny little microscopic cancers, that tumor can grow 16,000 times in size in just two weeks. Those same blood vessels allow cancer cells to get into the circulation, or metastasize, which is really why people die from cancer. It turns out that soy contains a molecule called genistein that cuts off the blood supply to cancers. In one study that I write about in the book, 5,000 women with breast cancer who ate more soy foods had lower mortality rates. And the ones who were successfully treated for breast cancer reduced their chance of recurrence by 30 percent. We know from that study how much soy you need: about 10 grams a day, roughly the amount in one cup of soy milk. Totally achievable. RELATED: 8 Myths About Metastatic Breast Cancer You Should Totally Stop Believing EH: You also highlight dark chocolate as a food that can help boost stem cells. How does that work, exactly? Li: A research study conducted at the University of California in San Francisco showed that chocolate that’s greater than 70 percent cacao can activate the body’s stem cells. The study looked at men with coronary disease, who had clogged blood vessels in their hearts. Researchers divided the subjects into two groups. They gave one group ultra-dark-chocolate hot cocoa and the other group hot cocoa that was not nearly as powerful. The subjects drank the cocoa twice a day for 30 days. The result was that the men who had the ultra-dark chocolate had twice the number of stem cells in their bloodstream. EH: When so many diet books are vilifying carbs, it was exciting to see you extol sourdough bread for its effect on the microbiome. Li: Sourdough bread is made with a bacteria that also happens to be a healthy gut bacteria, lactobacillus reuteri — which helps create that tangy flavor. Research studies have shown that this healthy gut bacteria not only boosts our immune system, it speeds our healing and causes our brains to release the social hormone oxytocin, which is the feel good hormone your brain makes when you hug someone you love. RELATED: What Are Probiotics and Are They Good for You? EH: I know some people who pick kiwi out of their fruit salad, but you make a case for it as DNA-protective. Li: A study done in Scotland gave healthy people either one or three kiwis to eat a day for three or four days. With just one kiwi a day, subjects were able to reduce damage to the DNA in their blood by 60 percent. And the ones who had three kiwis a day didn’t just protect the DNA, they helped the DNA build itself up by 60 percent. There are multiple bioactive compounds in kiwi: vitamin C, chlorogenic acid, quinic acid. Most fruits and vegetables have hundreds if not thousands of bioactive molecules, including many we haven’t identified yet. RELATED: 10 High-Antioxidant Foods That Prove Food Is Medicine EH: Finally, let’s talk about a food that gives the immune system a boost. You have a lot of good things to say about broccoli sprouts. Li: Broccoli sprouts are packed with really, really super-powerful bioactives. A study of young, healthy people in their twenties who were getting a flu vaccine involved giving some of the subjects a broccoli sprout shake once a day for four days before they got the vaccine. (The other subjects got a placebo shake.) The people who got the broccoli-sprout shake along with the vaccine had 22 times more immune cells in their blood than the subjects who got the placebo. RELATED: All About Broccoli: Nutrition, Health Benefits, How to Prepare It and More EH: Your book has a very pro-food approach. There’s no finger-wagging. Li: That’s the take-home message. If we make enough good decisions, we’re activating our health defenses to protect us even against the few bad decisions that we might make from time to time. I write about 200 different foods to choose from, so the good news is that we can start eating healthy by identifying the foods we already love. So you’re already building on the stuff you already like instead of going, oh God, I need to go on a cleanse. It’s turning healthy food into a positive action instead of a negative. This interview has been condensed and edited.
