Swedish scientists this week may have provided yet another reason to love chocolate, suggesting that women who have a couple of small chocolate bars every week were 20 percent less prone to debilitating strokes than those who eat none.
"Even consuming a relatively small amount of chocolate had quite a large impact on stroke risk," said Susanna Larsson, from Sweden's National Institute of Environmental Medicine in Stockholm, who led a large investigation that found chocolate reduced the risk of strokes caused by bleeds in the brain (hemorrhagic strokes) and strokes caused by a cutoff of blood flow through the brain (ischemic strokes).
However, Larsson said the benefit appeared proportional to the amount of chocolate in the women's diets. Subjects who ate about two bars of antioxidant-rich Swedish milk chocolate every week had "significantly reduced risk of stroke," compared with those who ate no chocolate, "suggesting that higher intakes are necessary for a potentially protective effect."
Larsson's two-bar approximation was based on the effects associated with consuming about 66.5 grams, or about 2.33 ounces, weekly.
The latest word on the chocolate's potential to protect the brain from stroke injury came from a study that followed 33,372 Swedish women, ages 49 to 83, for about 10 years, beginning in autumn 1997. During that decade, the researchers tallied 1,549 strokes among study subjects.
Researchers reviewed participants' responses to questionnaires about their diet during the last year. They then grouped the women by the frequency of their chocolate consumption, ranging from never to more than three times a day and looked for associations between strokes and the amount of chocolate the women regularly ate.
The findings, released today, appear in the Oct. 18 issue of the Journal of the American College of Cardiology.
But before you run down to the corner store to load up on chocolate bars, be aware of some caveats. First, the Swedish findings don't prove that chocolate protects against strokes; they suggest a link. Second, the findings won't likely translate as well in this country because 90 percent of the chocolate eaten Sweden at the time the study began was Swedish milk chocolate, which contains a higher concentration of antioxidant-rich cocoa solids (about 30 percent) than American chocolate bars.
Larsson suggested that Americans might want to stick with dark chocolate, but noted that U.S. chocolate bars need only contain 15 percent cocoa to be called sweet dark chocolate. Dark chocolate, she said, typically is lower in sugar than milk chocolate and contains more of the important antioxidants that give cocoa its heart-healthy properties.
Third, the study was based on people's self-reports of what they ate, and self-reports are notoriously unreliable. Fourth, chocolate is higher in fat, sugar and calories than many other foods, so it should be consumed in moderation, Larsson suggested, echoing nutritionists' frequent reminder: Adding chocolate to an otherwise balanced diet means cutting back elsewhere. Finally, like other research into chocolate's benefits, the newest findings need more follow-up.
Past studies have found that chocolate reduces blood pressure, which applies to stroke protection because hypertension is a major contributor to stroke. It also improves the way blood vessels function and helps the body use insulin to break down sugar to fuel the muscles and brain.
In late August, researchers announced at the European Society of Cardiology 2011 that a meta-analysis of previous studies found people who ate the most chocolate had a 37 percent lower risk of cardiovascular disease and a 29 percent lower risk of stroke than those who ate the least chocolate. Those findings also appeared in the British Medical Journal.