There is some good news for chocolate lovers.  A Japanese study suggests that dark chocolate can improve blood flow to heart muscle.  That is important because improved coronary blood flow mitigates the risk of chronic chest pain, or angina, and heart attacks, says Yumi Shiina PHD, of Chiba University in Japan .  Studies have shown that the sweet treat can also lower your blood pressure and reduce your risk of diabetes, she says.  Shiina credits flavonoids, a group of antioxidant compounds also found in red wine, tea and fruits and vegetables, with dark chocolate’s healthy effects.

Dark chocolate is rich in Flavonoids.  The study involved 39 healthy mean who ate 1.4 ounce candy bar of either dark chocolate or white chocolate daily for two weeks.  Shiina says the dark chocolate was rich in a potent flavonoid known as cacao polyphenol, while white chocolate contained no flavonoids.

The researchers measured what doctors call coronary flow velocity reserve (CFVR).  It is an indicator of the ability of the coronary arteries to dilate and allow more blood flow to the heart muscle tissue.  After two weeks, coronary circulation significantly improved in participants who ate dark chocolate.  There was no change among those who ate white chocolate.  Four times as many flavonoids per serving than red wine or tea, Shiina says.  That’s not to say you can indulge in dark chocolate with impunity, says Sidney Smith, MD, a past president of the American Heart Association and professor of medicine at the University of North Carolina. 

“You have to balance the fats and calories of the candy bar against the benefit of flavonoids”, he tells WebMD.  Shiina says that in the future, development of cacao polyphenol supplement would overcome the problem.  The study was presented at the American Heart Association Scientific Sessions 2007