Young and middle-age women whose diet included high levels of anthocyanins -- the flavonoids present in red and blue fruits such as strawberries and blueberries -- had a significantly reduced risk for myocardial infarction (MI), a large prospective study found. Women whose anthocyanin intake was in the highest quintile had a 32% decrease in risk of MI during 18 years of follow-up, according to Eric B. Rimm, ScD, of Harvard University, and colleagues. And in a food-based analysis, women who consumed more than three servings of strawberries or blueberries each week showed a trend towards a lower MI risk, with a 34% decrease compared with women who rarely included these fruits in their diet, the researchers reported online in Circulation.
"Growing evidence supports the beneficial effects of dietary flavonoids on endothelial function and blood pressure, suggesting that flavonoids might be more likely than other dietary factors to lower the risk of [coronary heart disease] in predominantly young women," they observed. A number of preclinical experiments have demonstrated cardioprotective effects of anthocyanins, including anti-inflammatory effects, plaque stabilization, and inhibition of the expression of growth factors. While studies have suggested that MI risk is increased in young and middle-age women who smoke or use oral contraceptives, little is known about the influence of diet in this population, whose risk may differ from that in older women. The younger women may have a greater likelihood of endothelial dysfunction and coronary vasospasm and less obstructive disease. Because dietary flavonoids -- found in vegetables, fruits, wine, and tea -- are recognized as benefiting endothelial function, the researchers looked at outcomes for 93,600 women enrolled in the Nurses' Health Study II who reported their consumption of various foods and their lifestyle factors every 4 years.