I was a participant in the COSMOS trial (it was fun!) examining possible benefits for older folks from cocoa flavonoids and an ordinary multivitamin (they used Centrum Silver). While the cocoa extract had no effect on cognition, the multivitamin did--it actually improved cognition! (Cardiovascular events and cancer results are reported elsewhere). Here's the summary:
Vitamins, minerals, and other bioactives in foods are important for normal brain function, and deficiencies in older adults may increase risk for cognitive decline. Dietary supplements are often recommended for cognitive protection, but supporting evidence is mixed. COSMOS investigators partnered with colleagues at Wake Forest University to test whether daily use of cocoa extract or a multivitamin for 3 years can reduce the risk of cognitive decline. The COSMOS-Mind sub-study enrolled 2,262 COSMOS participants aged 65 and older who completed annual telephone interviews to assess memory and thinking abilities. The investigators found that cocoa extract did not affect cognition. On the other hand, daily multivitamin use improved cognitive function. That is, participants assigned to the multivitamin group had higher cognitive test scores after 3 years than the participants assigned to the multivitamin-placebo group. The investigators estimated that taking the daily multivitamin slowed cognitive aging by approximately 60%, or the equivalent of 1.8 years over the 3 years of the study, but this finding requires confirmation in future research. “COSMOS-Mind provides the first evidence from a large randomized trial to show that regular use of a typical daily multivitamin may improve memory and thinking abilities in older adults,” noted COSMOS Co-Director Dr. Howard Sesso, who leads COSMOS with Dr. JoAnn Manson. However, the story continues to unfold as other investigators complete separate studies in COSMOS that dig more deeply into the effects of both cocoa extract and a multivitamin on different aspects of cognition and other aging-related outcomes.