A large-scale RCT of over 3,500 healthy older adults indicates that a diet low in flavanols, found in tea and many plant foods, could be partially responsible for age-related memory loss.
The study, published in PNAS and part of the COSMOS supplements trial, randomly assigned each subject to receive a daily flavanol pill or placebo pill for a year. The flavanol pill contained an equivalent amount of flavanols to that which adults are advised to get from food.
It found that those already eating a healthy diet with plenty of flavanols were unaffected; but those who reported consuming a low-flavanol diet and had lower baseline levels of flavanols saw their memory test scores increase compared with placebo.
For that group, flavanols only improved memory processes governed by the hippocampus that are related to cognitive ageing – not the parts of the brain affected by Alzheimer’s. The authors say their results suggest that there is an optimum amount of flavanol intake that can delay cognitive decline.
Journalists came to this online briefing to hear two of the study’s authors discuss their findings and their implications.
Prof Gunter Kuhnle, Professor of Nutrition and Food Science, University of Reading
Scott A. Small M.D., Boris and Rose Katz Professor of Neurology and Director of the Alzheimer’s Disease Research Center, Columbia University
This Briefing was accompanied by an SMC Roundup of Comments.