Deficiency of flavanol, found in certain fruits, vegetables, a driver of aging memory loss

New Delhi: A diet low in flavanols, or nutrients found in certain fruits and vegetables, was found to drive memory loss that came with aging, according to a new research.

The research, led by Columbia University and Brigham and Women's Hospital, US, said that it supported the emerging idea that that the aging brain required specific nutrients for optimal health, just as the developing brain required specific nutrients for proper development.

The study, published in the journal Proceedings of the National Academy of Sciences (PNAS), found that flavanol intake among older adults tracked with scores on tests designed to detect memory loss due to normal aging and that replenishing these bioactive dietary components in mildly flavanol-deficient adults over age 60 improved performance on these tests.

"The improvement among study participants with low-flavanol diets was substantial and raises the possibility of using flavanol-rich diets or supplements to improve cognitive function in older adults," said Adam Brickman, professor of neuropsychology at Columbia University and co-leader of the study.

Previous studies in Small's lab linked age-related memory loss to changes in the dentate gyrus, a specific area within the brain's hippocampus - vital for memory - and showed that flavanols improved function in this brain region.

Additional research, in mice, found that a particular bioactive substance in flavanols called epicatechin improved memory by enhancing the growth of neurons and blood vessels in the hippocampus.

Further, testing flavanol supplements in people, the researchers confirmed that the dentate gyrus was linked to cognitive aging and that flavanols improved memory by acting selectively on this brain region. Those starting out with a poor-quality diet saw the most impact.

For this study, more than 3,500 healthy older adults, most non-Hispanic and white, were randomly assigned to receive a daily flavanol supplement pill or a placebo pill for three years. The active supplement contained 500 milligrams (mg) of flavanols, including 80 mg epicatechins, an amount that adults are advised to get from food.

At the beginning of the study, all participants completed a survey assessing the quality of their diet, including flavanol-containing foods. Participants' short-term memory governed by the hippocampus was then assessed through web-based activities performed at home.

The tests were repeated after years one, two, and three.

At the end of the first year of taking the flavanol supplement, participants reporting a poorer diet consumption and lower baseline levels of flavanols saw their memory scores increase by an average of 10.5 per cent compared to placebo and 16 per cent compared to their memory at baseline.

Annual cognitive testing showed the improvement observed at one year was sustained for at least two more years.

The results, the researchers said, strongly suggested that flavanol deficiency is a driver of age-related memory loss because flavanol consumption correlated with memory scores and flavanol supplements improved memory in flavanol-deficient adults.

Further, the study also found that flavanols only improved memory processes governed by the hippocampus and did not improve memory mediated by other areas of the brain.

However, the researchers found that flavanol supplements had no effect on people who did not have a flavanol deficiency.