Below is an approximation of this video’s audio content. To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video.
Body fat is probably the most highly vascularized tissue in the body—meaning has the most blood vessels. In fact, each individual fat cell is surrounded by an extensive network of tiny blood vessels. And, since the formation of these blood vessels appears to play a critical role in fatty tissue growth and reduction, the regulation of angiogenesis––the blood vessel formation process––may contribute to weight gain and weight loss. So, researchers tried injecting anti-angiogenic drugs into overfed lab animals, and were able to induce profound weight loss in mice as well as in “nonhuman primates” (which is how scientists often refer to monkeys). The problem is that anti-angiogenic drugs can cause a variety of rare but fatal side effects. We may be willing to accept those risks in the context of cancer treatment, but when it comes to cancer prevention or obesity, anti-angiogenic diets would seem a safer bet (not to mention cheaper—anti-angiogenic drugs can cost $6,000 per dose). So, which foods are the most anti-angiogenic?
It’s interesting how they figured out that dietary components could be anti-angiogenic at all. Realizing that those eating plant-based diets were protected from diseases of excess angiogenesis, like cancer and diabetic vision loss, researchers took a group of plant-based eaters and starting pitting various components of their urine against the growth of human blood vessel cells harvested from discarded umbilical cords. The concentration of phytonutrients in the urine of vegetarians can be 30 times higher than that of the general population. Using this method, they identified a number of natural anti-angiogenic compounds in our diet. The question then became: could the levels required to block angiogenesis in a petri dish be reached in the bloodstream after eating a meal? The answer, researchers soon realized, is yes.
Anti-angiogenic concentrations of broccoli compounds can be reached in the bloodstream within an hour, eating less than three quarters of a cup of broccoli soup. So, these are totally doable kinds of quantities. You’ll note most of these compounds may cleared from our body within six hours, though, and fall back to nearly zero within 24 hours. So, we should strive to eat cruciferous vegetables at least once a day. Anti-angiogenic concentrations of b-cryptoxanthin can be reached within hours of eating two cups of red-fleshed papaya. One and a quarter cup of boiled onions may get you an anti-angiogenic dose of quercetin circulating in your blood in less than an hour. The level of protective soybean compounds that may be necessary has been found in the bloodstream of those eating ordinary Japanese diets. Now, I’m not dreaming up some sort of broccoli-papaya-onion-tofu casserole; these are just examples showing anti-angiogenic concentrations can be achieved within your bloodstream after eating reasonable serving sizes.
In general, the most concentrated dietary sources of polyphenols, the class of phytonutrients containing many of the anti-angiogenic compounds discovered to date, are herbs and spices. The only others to place in the top ten (out of more than 450 foods tested) were berries, cocoa powder, and ground flaxseeds. On a per-serving basis, most of the top contenders are berries, with artichokes leading the vegetables and whole grain rye leading the grains. Ironically, yogurt is a leading source in the United States, but only because most are fruit-flavored, with many containing berries as ingredients, whereas even plain soy yogurt makes it into the top 25.
For cancer prevention, researchers suggest the “constant consumption” of anti-angiogenic foods. Do we have evidence that it’s having an effect? Well, based on the analysis of more than a thousand tumors from one of Harvard’s studies of male health professionals, men eating the most tomato products had significantly less angiogenesis within their tumor, which then appeared to translate into a reduced risk of fatal disease. Yeah, but would the same anti-angiogenic potential of fruits and vegetables also help keep our bellies from growing? There’s only one way to find out!
A meta-analysis of more than a dozen randomized controlled trials of fruits and vegetable interventions for overweight individuals found six extra pounds of weight loss. But that could be from a whole variety of factors, like decreased calorie density from the fiber and water content. But maybe angiogenesis inhibition is playing a role? I originally planned on including a section on angiogenesis in How Not to Diet, but only wanted to include proven mechanisms of weight loss. So, it’s not in the book, but I thought it was so interesting I made these two videos about it.
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