If you're looking to assuage your guilt over buying those plump flown-in berries at the grocery store this time of year, there's a scientific finding for that.
An 18-year study of more than 93,000 nurses has found that women who ate three or more servings of blueberries and strawberries every week dramatically reduced their risk of having a heart attack by as much as one-third, according to a statement from the American Heart Association.
A subclass of the berries' dietary flavonoids, called anthocyanins, may help dilate arteries, counter the build-up of plaque and provide other cardiovascular benefits, the researchers suggest in the release.
"Blueberries and strawberries can easily be incorporated into what women eat every week," said Eric Rimm, senior author and an associate professor of nutrition and epidemiology at Harvard University's school of public health, in the statement. "This simple dietary change could have a significant impact on prevention efforts."
The researchers focused on blueberries and strawberries because of their popularity in the United States. But they point to other flavonoid-rich foods as possible good guys, too. Grapes and wine, blackberries, eggplant, and other fruits and vegetables could have similar effects.
According to the release, scientists from Harvard in the United States and the University of East Anglia in Britain looked at data from 93,600 women ages 25 to 42 registered with the Nurses' Health Study II. These women completed questionnaires about their daily diet every four years over 18 years – during which time 405 heart attacks occurred, the release reports.
The nurses who ate the most blueberries and strawberries had a 32-per-cent reduction in their risk of heart attack compared with women who ate the berries once a month or less – even in women who otherwise ate a diet rich in other fruits and vegetables, according to the release. Researchers controlled for known risk factors for heart disease, including age, high blood pressure, family history, body mass, exercise, smoking, or drinking alcohol or caffeine.
One of the keys appears to be eating berries long before you're at risk of heart problems.
"We have shown that even at an early age, eating more of these fruits may reduce risk of a heart attack later in life," said Aedín Cassidy, lead author and head of the department of nutrition at the University of East Anglia's medical school.
Blueberry and strawberry growers will no doubt pounce on the good news – although many are already pushing the heart benefits of their products.
Still some locavore pangs? Vow to snap up bushels of local fruit next summer and freeze them. Now, if you'll excuse, me I have a smoothie to make.