Which is more beneficial for memory: cocoa or vitamins?

Unexpected results from a phase 3 trial exploring the effect of multivitamins and cognition have now been published (Alzheimers Dement. Published online September 14, 2022).

Findings from a phase 3 study show daily multivitamin use, but not cocoa, is linked to a significantly slower rate of age-related cognitive decline.

This is the first large-scale, long-term randomized controlled trial to examine the effects of cocoa extract and multivitamins on global cognition. The trial's primary focus was on cocoa extract, which earlier studies suggest may preserve cognitive function. Analyzing the effect of multivitamins was a secondary outcome.

Showing vitamins, but not cocoa, was beneficial is the exact opposite of what researchers expected. Still, the results offer an interesting new direction for future study.

The COSMOS-Mind study is a sub-study to a larger parent trial called COSMOS. It investigated the effects of cocoa extract and a standard multivitamin-mineral (MVM) on cardiovascular and cancer outcomes in more than 21,000 older participants.

In COSMOS-Mind, researchers tested whether daily intake of cocoa extract vs placebo and a multivitamin-mineral vs placebo improved cognition in older adults.

More than 2200 participants aged 65 and older were enrolled and followed for 3 years. They completed tests over the telephone at baseline and annually to evaluate memory and other cognitive abilities.

Results showed cocoa extract had no effect on global cognition compared with placebo (mean z-score, 0.03; P = .28). Daily multivitamin use, however, did show significant benefits on global cognition vs placebo (mean z, 0.07, P = .007).

The beneficial effect was most pronounced in participants with a history of cardiovascular disease (no history 0.06 vs history 0.14; P = .01).

The study was not designed to measure multivitamin use as a primary outcome. In addition, nearly 90% of the participants were non-Hispanic White, which is not representative of the overall population demographics.