The research in the "Journal of the American College of Cardiology" does not prove cocoa lowers risk.
But the study notes women who ate about two chocolate bars a week had a 20 percent lower risk of have a stroke.
Researchers speculate the cocoa in chocolate bars, specifically the dark types, provide a protective benefit.
Swedish chocolate contains higher concentrations of cocoa compared to U.S. chocolate, so this study may not translate perfectly to U.S. women.
