Cocoa (dark chocolate) heart benefits

Effects of Sustained Ingestion of Cocoa on Endothelial Function in Adults

Flavonoids, a group of antioxidant compounds found in fruits and vegetables, are not generally labeled as essential nutrients, but play an important role in maintaining one's health. In fact, studies indicate that there is a strong inverse correlation between the consumption of foods rich in flavonoids – such as wine, green tea, fruits and vegetables – and cardiovascular disease. Cocoa or dark chocolate products are considered one of the most concentrated sources of flavonoids among commonly consumed foods. Since endothelial function has been used extensively to evaluate the effects of foods and nutrients on cardiac risk, researchers at the Yale Prevention Research Center in Connecticut conducted a trial to assess whether the consumption of cocoa would provide any sustained benefits on endothelial function.

Specifically, the team measured the function of the brachial artery to relax and expand to accommodate increased blood flow (also know as flow mediated dilation, or FMD) in adults with a body mass index (BMI) between 25 and 35 kg/m2. In the randomized, single-blind, placebo-controlled crossover study, 45 subjects recruited from the general population of southwestern Connecticut were randomly assigned to one of the three consumption groups: eight ounces of either cocoa without sugar, cocoa with sugar or placebo. For six weeks, all participants underwent endothelial function testing, assessing FMD of the brachial artery using high frequency ultrasound before and after the daily cocoa or placebo consumption.

Cocoa was considered a successful vehicle to improve endothelial function in this trial. Of the 39 subjects who completed the trial, FMD improved significantly in the groups consuming cocoa with no sugar (2.4 %) and cocoa with sugar (1.5 %) from baseline values when compared to placebo (-0.8 %).

"In this sample of healthy adults with BMI between 25 and 35 kg/m2, dark chocolate ingestion over a short period of time was shown to significantly improve endothelial function, leading our team to believe that greater benefit may be seen through a long-term, randomized clinical trial," said Valentine Yanchou Njike, M.D., of Yale Prevention Research Center, and co-investigator on this study. "While the findings from this study do not suggest that people should start eating more chocolate as part of their daily routine, it does suggest that we pay more attention to how dark chocolate and other flavonoid-rich foods might offer cardiovascular benefits."