Study: Dark chocolate could be the key to improving blood flow

As if we needed another reason to love chocolate: Researchers who studied 20 patients with peripheral artery disease found that the polyphenols in cocoa could increase blood flow, thus improving vascular health.

Peripheral artery disease (PAD) affects 20 percent of adults 70 and older in the U.S. and other Western countries, and makes it difficult for people to exercise and walk because of impaired blood flow. For this study, published in the Journal of the American Heart Association, researchers gave half of the participants 1.5 ounces of dark chocolate with at least 85 percent cocoa, and gave the other half 1.5 ounces of milk chocolate with less than 30 percent cocoa. The goal was to see if dark chocolate made it easier for patients to walk on a treadmill.

"After eating the dark chocolate, [the participants] walked an average 11 percent farther," study author Lorenzo Loffredo of Rome's Sapienza University told NPR's The Salt blog. An improvement in blood flow was seen in these patients, but "conversely, we did not observe effects on blood flow and on walking autonomy in PAD patients after milk chocolate consumption."

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Researchers said the polyphenols in dark chocolate — which are already known to help fight inflammation — are able to reduce oxidative stress and help the body form more nitric oxide, which causes blood vessels to dilate.

Don't run down to the nearest grocery store and stock up on dark chocolate just yet. Dr. Mark Creager of Brigham and Women's Hospital said that the "overall effect [of the dark chocolate] was relatively modest," and the 11 percent increase in walking only adds up to 40 more feet. "To put this in context, with other forms of treatment, such as supervised exercise training, maximal walking distance increases by approximately 100 percent."