Eating more berries has to be one of the most pleasant ways to improve your health. They are not only good for the brain, they may also prevent heart attacks, according to a new study. Eating three or more servings of berries per week helped women reduce their risk of a heart attack by up to a third. You don't need to wait for summer either — just buy them dried or frozen during the winter months.

Berries contain a subclass of dietary flavonoids called the anthocyanins, which may help dilate arteries, prevent or delay the buildup of plaque, and provide other cardiovascular benefits. "We were surprised at the magnitude of the effect," Aedin Cassidy, lead author of the study, told TheDoctor in an e-mail, "… [O]ur earlier paper had shown us that anthocyanins reduced blood pressure more in young women compared to older women and men, and that was what started us on this study,"

Anthocyanins, which may help dilate arteries, prevent or delay the buildup of plaque, and provide other cardiovascular benefits.

The scientists found that in young and middle-aged women, anthocyanins were the only flavonoids that reduced the risk of a heart attack, but according to Cassidy, as people age other dietary flavonoids may reduce the risk of cardiovascular events.

Investigators looked at data from 93,600 women ages 25 to 42 enrolled in the Nurses’ Health Study II. The women had completed questionnaires about their diet every four years for 18 years. Those women who reported eating the most blueberries and strawberries had a 32 percent reduction in their risk of heart attack compared to women who ate the berries once a month or less. This finding held true even for women who ate a diet rich in other fruits and vegetables.

Cassidy said that she and her team are planning long-term trials to examine the effects of anthocyanins on vascular health, so they can give more specific recommendations regarding the source of anthocyanins and the amount needed to reduce the risk of cardiovascular events. The study is published in the journal, Circulation.