Researchers tested the effects of a daily multivitamin on cognitive changes in a study of 573 participants with in-person visits in the COSMOS trial. The researchers also conducted a meta-analysis among over 5,000 non-overlapping participants across the three separate cognition studies within the COSMOS trial. Results showed a statistically significant benefit for cognition among participants taking the multi-vitamin compared to placebo, suggesting that a multi-vitamin could help prevent memory loss and slow cognitive aging among older adults.