USA: A recent study published in The American Journal of Clinical Nutrition has shed light on the effect of cocoa extract supplementation on cognitive function.
Findings from the clinic subcohort of the COSMOS (Cocoa Supplement and Multivitamin Outcomes Study) trial revealed that taking cocoa extract supplements containing 500 mg per day of cocoa flavanols had cognitive benefits for older adults who had lower habitual diet quality at the time of enrollment in the study.

However, cognitive benefits were not found among participants who already had healthy dietary patterns at the start of the study. The study, conducted by researchers at Mass General Brigham, included 573 older adults who underwent detailed, in-person cognitive testing.
Results from detailed neuropsychological assessments given over two years showed that daily cocoa extract supplementation, compared to placebo, had no overall benefits for global or domain-specific cognitive function. However, secondary analyses showed that participants with poor diet quality had cognitive benefits from taking the cocoa extract supplement.
The findings from this study which was done among COSMOS participants who presented in person for detailed cognitive testing-are consistent with the results from an earlier study that used a web-based cognitive assessment given over the internet to a separately recruited set of COSMOS participants.
COSMOS is an investigator-initiated large-scale, long-term clinical trial led by Brigham and Women’s Hospital. More than 21,000 older women and men were enrolled across the United States to participate in this randomized, double-blinded, placebo-controlled study to test whether taking daily supplements of a cocoa extract or a common multivitamin reduces the risk for developing heart disease, stroke, cancer, and other important health outcomes. Analyses of the data from COSMOS continue to yield insights about the connections between supplements and human health.
Reference:
Chirag M. Vyas, JoAnn E. Manson, M Vinayaga Moorthy, Nancy R. Cook, Olivia I. Okereke, Effect of cocoa extract supplementation on cognitive function: results from the clinic sub-cohort of the COSMOS trial, DOI:https://doi.org/10.1016/j.ajcnut.2023.10.031.