Cocoa beneficial for memory

Taking a daily flavanol supplement improves hippocampal-dependent memory in older adults who have a relatively poor diet, results of a large new study suggest.

The findings were published online May 30 in the Proceedings of the National Academy of Science.

Cognitive aging refers to the decline in cognitive abilities that are not thought to be caused by neurodegenerative diseases such as Alzheimer's disease and Parkinson's disease. Cognitive aging targets two areas of the brain: the hippocampus, which is related to memory function, and the prefrontal cortex, which is related to attention and executive function.

Previous research has linked flavanols, which are found in foods like apples, pears, berries, and cocoa beans, to improved cognitive aging. The evidence shows that consuming these nutrients might be associated with the hippocampal-dependent memory component of cognitive aging.

The new study, known as COcoa Supplement and Multivitamin Outcomes Study-Web (COSMOS-Web), included 3562 generally healthy men and women, mean age 71 years, who were mostly well-educated and non- Hispanic/non-Latinx White individuals.

Participants were randomly assigned to receive oral flavanol-containing cocoa extract (500 mg of cocoa flavanols, including 80 mg of epicatechin) or a placebo daily.

Researchers stratified participants into tertiles on the basis of diet quality as measured by the Healthy Eating Index (HEI) scores. Those in the lowest tertile had poorer baseline hippocampal-dependent memory performance but not memory related to the prefrontal cortex.

The flavanol intervention improved performance on the ModRey test compared with placebo in participants in the low HEI tertile (overall effect: d = 0.086; P = .011) but not among those with a medium or high HEI at baseline.

The study included only older adults so it's unclear what the impact of flavanol supplementation is in younger adults. But cognitive aging "begins its slippery side" in the 40s. If this is truly a nutrient that is taken to prevent that slide from happening, it might be beneficial to start in our 40s.

Though the exact mechanism linking flavanols with enhanced memory isn't clear, there are some clues; for example, research suggests cognitive aging affects the dentate gyrus, a subregion of the hippocampus.