Dark Chocolate May Lighten the Load on Arteries

(HealthDay News) -- Delicious nibbles of dark chocolate may also boost the function of vital endothelial cells that line the inside of blood vessels, a new U.S. study suggests.

Cocoa is rich in a group of antioxidant compounds called flavonoids, which are also found in fruits and vegetables, wine and green tea. Research suggests that consumption of foods rich in flavonoids may decrease the risk of cardiovascular disease.

The study, conducted by researchers at the Yale Prevention Research Center in Connecticut, included 45 healthy people with a body mass index (BMI) between 25 and 35 kg/m2. The participants were divided into three groups that ate either eight ounces of cocoa without sugar; cocoa with sugar; or a placebo.

BMI is a measure of body fat based on height and weight. A BMI reading of 25-29.9 is an indicator of overweight, while a reading of 30 or more indicates obesity.

For six weeks, the participants underwent endothelial function testing. This was done by using high frequency ultrasound to measure the ability of the brachial artery (which runs from the shoulder to the elbow) to relax and expand in order to accommodate increased blood flow -- a test called flow mediated dilation (FMD).

The study found that FMD improved significantly (2.4 percent) in the group that consumed cocoa with no sugar, compared with 1.5 percent in the group that ate cocoa with sugar. There was a 0.8 percent decrease in FMD in the group that ate the placebo.

"In this group 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," co-investigator Dr. Valentine Yanchou Njike said in a prepared statement.

"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," Njike said.

The study was expected to be presented March 27 at the American College of Cardiology's Annual Scientific Session in New Orleans.

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