Local Study Proves Cocoa, Dark Chocolate

Beneficial To Heart Health

DERBY — According to a study conducted by the Yale-Griffin Prevention Research Center, and just published in the American Journal of Clinical Nutrition, ingestion of solid dark chocolate and hot cocoa beverages demonstrates benefit to blood vessels, a marker of cardiac risk.

Recent studies suggest vascular health benefits associated with dark chocolate. This is of particular interest given the popularity of chocolate, and the potential it offers for people to derive health benefits from a food category associated with high palatability and indulgence.

Evidence is accumulating that some forms of cocoa and chocolate, rich in flavonoids, may have the potential to improve cardiovascular health. This current study was designed to examine the acute effects of solid dark chocolate and liquid cocoa (with and without sugar) intake on endothelial function, or blood vessel reactivity, and blood pressure in overweight but otherwise healthy adults who are at risk for cardiovascular disease due to elevated body mass index (BMI). 

The study included two phases, acute and sustained, to determine immediate and longer term effects of eating chocolate. The results of the acute phase are reported in the current issue of the American Journal of Clinical Nutrition with results of the sustained phase expected to be published in the near future.

A total of 45 overweight but otherwise healthy adults were randomly assigned to consume a solid dark chocolate bar (containing the equivalent of 22g cocoa powder) and a cocoa-free placebo bar, and again to consume sugar-free liquid cocoa (containing 22g cocoa powder), sugared cocoa (containing 22g cocoa powder) and a placebo (containing 0g cocoa powder).

Immediately before and two hours after consuming the chocolate or cocoa beverage, subjects underwent endothelial function testing by the use of high resolution ultrasound, and blood pressure measurement.

Results showed that the acute ingestion of both solid dark chocolate and cocoa beverages improved endothelial function and lowered blood pressure in these overweight adults. The results were stronger with the sugar-free beverage preparation; it is believed that the sugar content attenuates these effects, and sugar-free preparations augment them. 

This study was funded by The Hershey Company and the Centers for Disease Control and Prevention (CDC). The solid dark chocolate product, Hershey’s Extra Dark Chocolate, and cocoa powder, Hershey’s Natural Cocoa, used for this study are available commercially. 

“To our knowledge, this is the first study to compare the acute effects of regular and sugar-free cocoa on endothelial function and blood pressure, and to examine the effects of solid dark chocolate and liquid cocoa in the same subjects,” says David L. Katz, MD, MPH, principal investigator of the study, and director of the Prevention Research Center. 

“Our study demonstrated impressive enhancement of endothelial function following the acute consumption of dark chocolate and cocoa, which were even better with a sugar-free cocoa,” Dr Katz added. “Cocoa clearly has favorable acute effects on the vasculature, and it appears that sugar attenuates these effects. When cocoa is consumed without the competing effects of sugar, the vascular benefit observed is stronger. This study is exciting because it shows various preparations of dark chocolate, a food long associated with pleasure, all have health promoting properties as well.”

According to the researchers, further investigation is warranted to determine longer term effects of habitual solid and liquid cocoa intake; optimal dosing of chocolate for cardiovascular benefit; variation in beneficial effects among diverse populations; and ultimately, the influence of dietary cocoa intake on cardiac events.