Blog | Tuesday, October 11, 2011

QD: News Every Day--More support that chocolate prevents strokes


More research suggests that chocolate seems to lower the risk of stroke, according to a Swedish study that found that women who ate 66.5 grams each week, or about two chocolate bars, had a 20% lower risk.

Swedish chocolate! by roland via Flickr and a Creative Commons licenseResearch correspondence in the Oct. 18 Journal of the American College of Cardiology reported on 33,372 women age 49 to 83 completed a questionnaire in 1997 that included approximately 350 items concerning diet and other lifestyle factors. Women were asked to indicate how often on average they had consumed chocolate and 95 other foods during the previous year. There were 8 pre-defined consumption categories ranging from never to three or more times a day. They were excluded if they had a history of cancer, stroke, coronary heart disease, or diabetes.

Researchers then recorded onset of the first stroke and the type of stroke from January 1998 through December 2008 as recorded in the Swedish Hospital Discharge Registry.

During a mean follow-up of 10.4 years, there were 1,549 strokes, including 1,200 cerebral infarctions, 224 hemorrhagic strokes, and 125 unspecified ones. Chocolate consumption was inversely associated with risk of total stroke, cerebral infarction, and hemorrhagic stroke. Relative risk [RR] for a 50 g/week increase of chocolate consumption were 0.86 (95% confidence interval [CI], 0.77 to 0.96) for total stroke, 0.88 (95% CI, 0.77 to 0.99) for cerebral infarction, and 0.73 (95% CI, 0.54 to 0.99) for hemorrhagic stroke. The difference in risk estimates for cerebral infarction and hemorrhagic stroke was not significant (P=0.28).

The association for total stroke persisted after excluding the first year of follow-up (50 g/week increase in intake RR, 0.86; 95% CI, 0.76 to 0.96). In stratified analysis by hypertension, the multivariable RRs of total stroke for 50 g per week increment of chocolate consumption were 0.89 (95% CI, 0.73 to 1.09) for women with a history of hypertension and 0.85 (95% CI, 0.74 to 0.97) for women without hypertension.

Researchers wrote that chocolate is presumed to have heart benefits due to the flavonoids in cocoa that have antioxidant properties. Dark chocolate consumption has also been shown to reduce blood pressure, improve endothelial and platelet function and to improve insulin resistance. Previous research suggested that dark chocolate inhibits the activity of the angiotensin-converting enzyme.

The association between chocolate consumption and stroke is expected to be stronger with higher concentration of cocoa in Swedish chocolate, which is 30% cocoa, compared to chocolate in the U.S., which is generally 15% cocoa, they noted. More large prospective studies are needed to assess the association between chocolate and stroke, and to distinguish between the vascular benefits of milk versus dark chocolate.

This Swedish study comes on the heels of a recent meta-analysis showing that people who ate the most chocolate had a 37% lower risk of cardiovascular disease and a 29% lower risk of stroke compared with individuals who ate the least amount of chocolate.