Strawberries and blueberries contain high levels of compounds called polyphenolics, which researchers say can help the brain to carry out vital "housekeeping" functions.
Researchers from the Human Nutrition Research Center on Aging at Tufts University and University of Maryland Baltimore County studied the effects of berries on the brains of rats, looking specifically at the berries' effect on clearing toxic accumulation from the brain, the researchers said.
The scientists fed rats a berry diet for two months and then looked at their brains after irradiation, a model for accelerated aging. All of the rats were fed berries two months prior to radiation and then divided into two groups -- one was evaluated after 36 hours of radiation and the other after 30 days while continuing to eat a berry diet.
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"After 30 days on the same berry diet, the rats experienced significant protection against radiation compared to control," said investigator Dr. Shibu Poulose. "We saw significant benefits to diets with both [strawberries and blueberries], and speculate it is due to the phytonutrients present."
"Most diseases of the brain such as Alzheimer's and Parkinson's have shown an increased amount of toxic protein," said Poulose. "Berries seem to promote autophagy, the brain's natural housekeeping mechanism, thereby reducing the toxic accumulation."
The study, announced April 21, was funded by the USDA and a grant from NASA.
In a separate study published last year in the Annals of Neurology, US scientists found that women who eat plenty of blueberries and strawberries experience slower mental decline with age than women who consume fewer of the flavonoid-rich fruits. Based on a survey of more than 16,000 women who filled out regular questionnaires on their health habits from 1976 through 2001, the findings showed that those who ate the most berries delayed cognitive decline by up to 2.5 years.