The evidence keeps percolating that coffee might have benefits beyond just helping you wake up in the morning. The latest such finding, from a large Swedish study, links coffee drinking to a reduced risk of stroke in women.
Although their study wasnt designed to prove cause and effect, Susanna C. Larsson, PhD, of the Karolinska Institute in Stockholm, and colleagues commented in the journal Stroke, Given that coffee is one of the most popular beverages consumed worldwide, even small health effects of substances in coffee may have large public health consequences.
Larsson and colleagues analyzed data on 34,670 women, initially free of cardiovascular disease and cancer, participating in the Swedish Mammography Cohort. When that study began, the women filled out a questionnaire on diet that included coffee consumption; overall, they averaged three cups of coffee a day. Although the questionnaire didnt ask about regular versus decaffeinated consumption, the researchers noted that few Swedes drink decaf.
During an average 10.4 years of followup, a national hospital-discharge registry recorded 1,680 strokes among the participating women. After adjusting for other stroke risk factors such as smoking, researchers found that women drinking at least one cup of coffee daily were 24% less likely to suffer a stroke. Drinking more coffee didnt seem to be associated with even lower stroke risk, however; instead, researchers concluded, the risk appeared to be increased among women with low or no consumption of coffee compared to daily coffee drinkers.
Larsson and colleagues suggested that antioxidant polyphenols in coffee might be responsible for the association with lower likelihood of stroke. These coffee compounds could improve blood-vessel function and insulin sensitivity and reduce inflammation. Previous studies have shown that drinkers of both regular and decaf coffee are less prone to strokes, suggesting that caffeine doesnt get the credit for any possible protective benefit.
Jeffrey Blumberg, PhD, director of Tufts HNRCA Antioxidants Research Laboratory, comments, There is a biological plausibility for such an effect, though I feel it is more likely due to the phenolic acids, e.g., chlorogenic acid, than to the polyphenols in the beverage. The fact that other studies have found somewhat similar results provides further confidence in the association.
The Swedish researchers couldnt say whether their findings might also extend to men. In another study, however, Larsson found an association between coffee consumption in Finnish male smokers and lower risk of stroke. And in 2010, English scientists reported to the American Stroke Association conference that both men and women who consumed at least a cup of coffee daily were 30% less likely to suffer a stroke over a 12-year span.
TO LEARN MORE: Stroke, online before print; abstract at dx.doi.org/10.1161/STROKEAHA.110.603787. What You Can Do to Prevent a Stroke, Healthletter Special Supplement, August 2010.