Blueberry Extracts Boost Brain Function

A single dietary change has allowed laboratory animals with a genetic tendency toward Alzheimer's disease to perform as well as healthy peers in maze tests. Agricultural Research Service (ARS) scientists noted the diet-induced behavioral differences in the Alzheimer's-prone animals after feeding them blueberry extracts from the equivalent of their early adulthood to early middle age.

Study author James Joseph heads the Neuroscience Laboratory at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University in Boston, Mass. He and coauthors reported the findings in Nutritional Neuroscience. ARS is the U.S. Department of Agriculture's chief scientific research agency.

The researchers studied mice that carried a genetic mutation for promoting increased amounts of amyloid beta in the brain. This protein molecule, or fragment, builds up as the telltale neuritic plaque, or "hardening of the brain," seen in Alzheimer's disease.

For the study, beginning with rats at four months of age—which is the equivalent of early adulthood in humans—half of the brain-plaqued group was fed a diet that included blueberry extract for eight months. The other half was fed standard rat chow, as was a control group of mice that didn't carry the amyloid-plaque mutation.

When the rats reached 12 months of age—the equivalent of early middle-age in humans—all groups were tested for their performance in a maze. The brain-plaqued mice that were fed the blueberry extract performed as well as the healthy control mice, and they performed much better than their brain-plaqued peers fed standard chow.

The team found increased activity of a family of enzymes, called kinases, in the brains of the amyloid-plaqued mice that were fed blueberry extract. Two of the kinases found, ERK and PKC, are important in mediating cognitive function, such as conversion of short-term to long-term memory.

Read more about this research in the August 2007 issue of Agricultural Research magazine.