Willie Wonka fans have more to celebrate this week -- even more evidence chocolate is good for the heart.
A study published by the journal Hypertension on Monday adds to the growing body of evidence showing the health benefits of everyone's favorite sweet treat. The heart-healthy effects come from chemicals called flavonoids that are found in cocoa powder.
"Flavonoids are antioxidants that reduce blood pressure by relaxing blood vessels," said Dr. Nieca Goldberg, the chief of Women's Cardiac Care at Lenox Hill Hospital in New York. "Flexible blood vessels are resistant to cholesterol buildup in the arteries."
The new study focused on 20 people with untreated hypertension, half of whom ate a bar of dark chocolate every day for two weeks. The other half ate white chocolate, which doesn't contain flavonoids.
The small size of the experiment made some experts cautious of jumping to conclusions, however. "The study is interesting," said Goldberg, "but [it's] not enough for me to start writing prescriptions for chocolate."
Nevertheless, the effects seen in the group of dark chocolate eaters were significant. Those who ate a bar of chocolate every day had a drop in blood pressure, an increase in blood flow, and were more sensitive to insulin, a hormone that regulates sugar in the body.
"The blood pressure-lowering effect of dark chocolate in this study compares favorably with the one achieves with commonly used anti-hypertensive drugs," said Dr. Frank Messerli, director of the Hypertension Program at St. Luke's-Roosevelt Hospital in New York.
But not just any old bar of chocolate will do. To get those flavonoids, the chocolate needs to have a lot of cocoa powder in it. In other words, it needs to be dark chocolate. It's the flavonoids, in part, that give dark chocolate its bitter taste.
Most commercial chocolate has had its cocoa content diluted with fats and sugars to make it sweeter. The way that chocolate is processed also tends to squeeze out the flavonoids. "Once the refining process gets going, the flavonoids start dropping like flies," said dietician Keith Ayoob of the Albert Einstein College of Medicine in New York.
And much of the chocolate used for research purposes had been beefed up with extra flavonoids. "Most chocolate available commercially has very low flavonoid content," said Messerli.
So what's a chocolate lover to do?
Katherine Tallmadge, who has studied the health benefits of chocolate for the American Dietetic Association, said to look for chocolate that is less processed and has the highest percentage of cocoa possible. Buying pure cocoa powder will help you cut down on calories. Also, Tallmadge recommends avoid anything that has been "Dutch processed" -- a refining technique that is a flavonoid killer.
You won't find the flavonoid content listed anywhere on the nutritional label for most chocolate. The one exception to that rule is Dove Dark chocolate. The chocolate used in the study delivered almost 90 milligrams of flavonoids. According to Mars Inc., the Dove Dark bar has 150 milligrams.