Effect of cocoa extract supplementation on cognitive function: results from the clinic subcohort of the COSMOS trial.
Level 2 - randomized trial
Individual randomized controlled trial
PubMed 38070683 · doi:10.1016/j.ajcnut.2023.10.031
What was done
In the COSMOS-Clinic subcohort of the 2 × 2 factorial randomized controlled trial (COSMOS), 573 US adults aged ≥60 years (mean age 69.6 ± 5.3; 49.2% female) underwent detailed in-person neuropsychological testing at baseline, and 492 completed the 2-year follow-up. Participants received daily cocoa extract (500 mg flavanols/day, including 80 mg (-)-epicatechin) or placebo. The primary outcome was 2-year change in global cognition (mean z-score across 11 tests), with secondary outcomes of episodic memory and executive function/attention analyzed using repeated measures models.
What was found
Cocoa extract supplementation showed no significant benefit over placebo after 2 years on: - Global cognition: mean difference -0.01 standard deviation units (SU) (95% CI: -0.08, 0.05) - Episodic memory: mean difference -0.01 SU (95% CI: -0.13, 0.10) - Executive function/attention: mean difference 0.003 SU (95% CI: -0.07, 0.08) Subgroup analyses uncorrected for multiple testing suggested potential cognitive benefits in individuals with poorer baseline diet quality.
Why it matters
In a randomized trial with in-person multi-domain cognitive testing, cocoa flavanol supplementation did not slow cognitive decline or improve cognitive function in older adults over 2 years.
Limits
The analysis was limited to a clinic subcohort of 573 participants (492 completed), representing a fraction of the full COSMOS trial. The 2-year duration may be too brief to detect subtle divergence in late-life cognitive trajectories, and potential benefits in the subgroup with poor diet quality were exploratory and uncorrected for multiple comparisons.
Cited by
- supports In the COSMOS trial, cocoa flavanol supplementation improved cognitive outcomes only in individuals who had poor diet quality at baseline.