Why Cocoa May Help Heart Health
Antioxidants Are Key -- and Not Always Saved in Cocoa Processing
What About Chocolate?
Chocolate also contains flavonoids, "but the problem with chocolate is the burden of fat it carries," Hollenberg says.
"So it's hard to make chocolate a health food, whereas the cocoa has the fat squeezed out of it, so it could be a health food," he continues.
"Now, I'm hoping that people actually make a flavonoid-rich cocoa that will be available for sale and that people incorporate into their diets. It hasn't happened yet, but I'm hoping it will," says Hollenberg.
The study he worked on was backed by candy maker Mars Inc. Here is an overview of the tests that were done and their results.
In one set of tests, healthy young men drank beverages made from cocoa powder that was high or low in a type of flavonoid called flavonols. Mars supplied the cocoa powder.
Each man tried one of the drinks after an overnight fast. More than two days later, they fasted again and then tried the other drink. Their blood vessels relaxed more after drinking the flavonoid-richer cocoa.
Next, scientists isolated and purified cocoa's flavonols. Some participants got a drink containing those flavonols; others got water without flavonols. Blood vessels were more relaxed after drinking flavonols but not pure water. That finding suggests that those particular flavonols -- not something else in cocoa -- are important, the researchers write.
Lab tests on rabbits' hearts also backed the findings. The specific flavonol that stood out was called epicatechin, the study shows.
The researchers also headed to Panama, where the Kuna Indians traditionally drink three or four cups of homemade cocoa per day.
The Kuna Indians who live in their traditional location -- Panama's San Blas islands -- have rare cases of high blood pressure and heart disease compared with Kuna Indians who move to Panama's mainland, who drink less than four cups of the cocoa per week.
Stress and other dietary practices don't explain the pattern, Hollenberg says.
"You take all the known environmental factors and put them together, and they don't bring blood pressure that low. So we think it really is something special about eating these flavonoids," he says.