Transcript: Dark Chocolate and Artery Function
Chocolate: beauty, the beast, or both? Although cocoa itself is frequently found in foods like chocolate which can contain high levels of fat and sugar, the cocoa powder itself may have beneficial effects in a number of chronic disease conditions including heart disease.
Flow-mediated dilation, measured in the main artery of the arm, is considered one of the best measures of arterial function, a predictor of cardiovascular mortality. A little bit of cocoa doesn't do anything, but a little more, or a lot gives one a significant boost in arterial function within hours of consumption. How much does it take? Not much, just about a teaspoon of natural cocoa powder, which would be like a tablespoon or more of Dutched cocoa.
Now, makes you a little suspicious that the author works in Hershey, Pennsylvania, at the Hershey Medical center, and indeed has accepted money from our largest chocolate manufacturer’s Center for Health and Nutrition, conveniently located near the intersection of Chocolate and Cocoa Avenue.
Putting together all of the best available science though, dozens of randomized controlled trials, arterial function was significantly improved within hours and after weeks and months of chronic cocoa consumption. It’s always difficult to tease fact from fiction when such powerful financial interests are involved. Many of these studies were funded by industry as well, and as in all areas of research, evidence suggests that industry funding is associated with pro-industry conclusions, but even after removing those studies funded by industry, they found the same protective effect.
The reason they measure arterial function in the arm rather than where you really need it—the coronary arteries of the heart, is that that would require an angiogram, which is a much more invasive procedure. But if you were able to find people already scheduled for an angiogram anyway… Double-blind randomized trial finds that dark chocolate actually opens up coronary arteries. And when they did what’s called a cold pressor test, where they plunge your hand into a bucket of ice water, which normally causes your arteries to constrict, after dark chocolate, they dilated. Dark chocolate may also improve blood flow to the heart of our kidneys.
Because chocolate also contains fat and sugar, we have to be careful, though. Furthermore, most chocolate products are manufactured with milk, a compound known to influence antioxidant capacity in our blood. Even if milk chocolate had the same flavonoid phytonutrient content as dark chocolate, the antioxidant effect of cocoa is potentially weakened in the blood when milk is consumed.
So not only are there triple the antioxidants in dark compared to milk chocolate, but the milk actively works against the effects in the human body. Give dark chocolate, and get a nice spike in the antioxidant power of your bloodstream within an hour. Give milk chocolate, nothing, but if you eat that same dark chocolate with a cup of milk, the benefit is suppressed. The addition of milk, either in your stomach or in the chocolate, inhibits the within body antioxidant activity of chocolate and the absorption into the bloodstream of one of the target phytonutrients.
The sugar isn’t good for us either. Sugar impairs arterial function. One bottle of soda’s worth of sugar can cripple arterial function. That’s why sugar-free cocoa improves arterial function better than the same amount of cocoa with sugar added. So, eliminating sugar appears to amplify the beneficial effects of cocoa.
Bottom line, although the positive effects of chocolate and cocoa products seem apparent, precautions exist when we’re talking about the calories, fat, and sugar in chocolate. Cocoa powder, then offers the best of both worlds. Although not as tasty, cocoa-based products with little or no sugar or fat are certainly preferred. And you can make them tasty as I note in my healthy chocolate milkshake recipe, and my healthy chocolate ice cream video.
To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.
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