April 26, 2012 -- Eating berries at least once a week may protect the brain from age-related memory loss, a large new study shows.
The study included more than 16,000 women who are taking part in the Nurses' Health Study.
Researchers have been keeping tabs on the women's diets since 1980. Between 1995 and 2001, researchers also measured the mental function of women who were over 70 and had not had a stroke.
Mental functioning was measured during three telephone interviews that were spaced about two years apart. In the interviews, researchers asked the women to recall details from a paragraph they'd just heard, for example, or to remember the order of words or numbers in a list.
When researchers compared women who ate the most blueberries and strawberries to those who ate the fewest, they found that those who ate the most had a slower rate of developing memory problems. The difference was equal to about two-and-a-half years of aging.
"This is pretty compelling evidence to suggest that berries do appear to have memory benefits," says researcher Elizabeth E. Devore, ScD, instructor in medicine at Brigham and Women's Hospital in Boston.
What may be even better news is that the biggest berry eaters in the study weren't eating mounds of them every day. On average, they were eating a single half-cup serving of blueberries or two half-cup servings of strawberries each week.
"These are simple interventions that appear to have pretty healthful effects," Devore says.
The study can't prove that berries protected the women's brains directly.
In fact, women in the study who ate berries regularly also got more exercise and had higher incomes -- two factors that are also linked to having better health.
But researchers say that even after they adjusted their results to account for differences like that, having a diet high in fruits and vegetables, particularly berries, still appeared to be linked to having a sharper memory.
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The study, which is published in the Annals of Neurology, builds on smaller studies in mice and humans that have suggested that berries may benefit the brain.