They examined 31,823 Swedish women between the ages of 48-83 who did not have diabetes or a history of heart failure. The women were followed from January 1, 1998 through December 31, 2006.
Chocolate intake was categorized as no regular chocolate intake, 1-3 servings of chocolate per month, 1-2 servings per week, 3-6 servings per week and one or more servings per day.
Compared to the women who ate no chocolate at all, the rate of heart failure was 26 percent lower among those who consumed 1-3 servings of chocolate per month and 32 percent lower among those who consumed 1-2 servings of chocolate per week.
However, the rate of heart failure was similar among women with no regular chocolate intake and those who consumed 3-6 servings per week or more.
Researchers believe the quality of the chocolate matters. They said in the European Union, dark chocolate must consist of at least 35 percent cocoa solids but in the United States the minimum is set at 15 percent.
Chocolate is one of the most concentrated sources of flavanoids, a subclass of polyphenols which have antioxidant properties.
