LOS ANGELES, Aug. 16 (Xinhua) -- Women who take a small amounts of dark chocolate may have a lower risk of heart failure, a new study has found.
To determine the relationship between dark chocolate and heart failure, researchers at Harvard Medical School studied the chocolate-eating habits of 31,823 Swedish women, aged 48 to 83, reported over a period of nine years.
The findings showed that women who ate one to three servings of chocolate (20 to 30 grams) a month had a 32-percent reduced risk of heart failure, compared to women who did not eat the sweet regularly.
However, if women eat too much dark chocolate (one to two servings a week), that protective effect goes away, according to the study published in the August issue of Circulation: Heart Failure.
That is to say that consuming dark chocolate three to six servings a week may raise the risk of heart failure by 23 percent, the study noted.
"At least for women, consumption of chocolate seems to be associated with a decreased risk of heart failure, but the protective effect was only seen with relatively small amounts of consumption, less than one serving a day," said senior study author Dr. Murray Mittleman.
"With higher levels, the benefit appears to be lost and perhaps even (have) a detrimental effect."
While the redeeming health qualities of chocolate have been extolled before, other studies had not specifically looked at heart failure, Mittleman said.
"Up until now, (researchers) were focused on other outcomes, such as the effects on blood pressure and other things," he explained.
And those studies did find that moderate amounts of chocolate do seem to lower blood pressure.
"The beneficial effects on blood pressure are likely an important part of the mechanisms of what we're observing," said Mittleman, who is director of the Cardiovascular Epidemiology Research Unit at Beth Israel Deaconess Medical Center at Harvard Medical School in Boston.
"Chocolate is still very calorie-dense, and there's fat and sugar that comes along with it, so moderation is a very important part of the story," Mittleman said.
The chocolate measured in this study was mostly high-quality dark chocolate without a lot of added sugar, though it was commercially available, he said.
And the higher the cocoa content, the better. The cocoa content of the chocolate consumed by the women in this study was about 30 percent whereas, in the United States, dark chocolate is only required to contain 15 percent cocoa solids.