A large-scale study led by researchers at Columbia University and Brigham and Women’s Hospital/Harvard has established that a diet low in flavanols—phytochemicals found in certain fruits and vegetables—drives age-related memory loss in adults over age 60.
The study found that flavanol intake among healthy older adults tracked with scores on tests designed to detect memory loss due to normal aging.
What’s more replenishing these dietary components in mildly flavanol-deficient adults improved performance on memory tests.
The findings also support the emerging idea that the aging brain requires specific nutrients for optimal health, just as the developing brain requires specific nutrients for proper development.
Age-related memory loss linked to changes in hippocampus
The current study builds on over 15 years of research linking age-related memory loss to changes in the dentate gyrus, a specific area within the brain’s hippocampus—a region that is vital for learning new memories—and showing that flavanols improved function in this brain region.
Additional research in mice, found that flavanols—particularly a bioactive substance in flavanols called epicatechin—improved memory by enhancing the growth of neurons and blood vessels and in the hippocampus.
What are flavanols?
Flavanols belong to the flavonoid family, a large group of more than 6,000 protective plant compounds found fruits, vegetables and many other plant foods.
Specifically, you’ll find flavanols in apples, apricots, strawberries, peaches, plums, cocoa powder, dark chocolate, tea, pecans, pistachios and cinnamon.
About the latest study
In the new study, the Columbia team collaborated with researchers at Brigham and Women’s Hospital studying the effects of flavanols and multivitamins in COSMOS (COcoa Supplements and Multivitamin Outcomes Study).
The current study, COSMOS-Web, was designed to test the impact of flavanols in a much larger group and explore whether flavanol deficiency drives cognitive aging in this area of the brain.
More than 3,500 healthy older adults were randomly assigned to receive a daily flavanol supplement (in pill form) or placebo pill for three years. The active supplement contained 500 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 that assessed the quality of their diet, including foods known to be high in flavanols.
Participants then performed a series of web-based activities in their own homes, designed and validated by Brickman, to assess the types of short-term memory governed by the hippocampus. The tests were repeated after years one, two, and three.
More than a third of the participants also supplied urine samples that allowed researchers to measure a biomarker for dietary flavanol levels. The biomarker gave the researchers a more precise way to determine if flavanol levels corresponded to performance on the cognitive tests and ensure that participants were sticking to their assigned regimen (compliance was high throughout the study).
Flavanol levels varied moderately, though no participants were severely flavanol-deficient.
People with mild flavanol deficiency benefited the most
Memory scores improved only slightly for the entire group taking the daily flavanol supplement, most of whom were already eating a healthy diet with plenty of flavanols.
But at the end of the first year of taking the flavanol supplement, participants who reported consuming a poorer diet and had lower baseline levels of flavanols saw their memory scores increase by an average of 10.5% compared to placebo and 16% 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 strongly suggest that flavanol deficiency is a driver of age-related memory loss, the researchers say, because flavanol consumption correlated with memory scores and flavanol supplements improved memory in flavanol-deficient adults.
“Age-related memory decline is thought to occur sooner or later in nearly everyone, though there is a great amount of variability,” said the lead researcher. “If some of this variance is partly due to differences in dietary consumption of flavanols, then we would see an even more dramatic improvement in memory in people who replenish dietary flavanols when they’re in their 40s and 50s.”
Source: Proceedings of the National Academy of Sciences, May 30, 2023.
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