Dr. JoAnn Manson, a respected professor of medicine at Harvard Medical School and Brigham and Women’s Hospital, recently highlighted the findings of a significant randomized clinical trial called COSMOS (Cocoa Supplement and Multivitamins Outcome Study). The trial suggests that multivitamins have the potential to enhance memory and slow cognitive aging when compared to a placebo. This trial represents the second COSMOS study demonstrating the positive effects of multivitamins on memory and cognition. The research was conducted in collaboration between Brigham and Columbia University and was published in the esteemed American Journal of Clinical Nutrition. Dr. Manson would like to acknowledge her role as a co-author of the study, alongside Dr. Howard Sesso, who co-leads the primary COSMOS trial.
Maintaining memory and cognitive function holds critical importance, particularly among older adults. Nutritional interventions are known to play a significant role, as the brain requires various nutrients for optimal health. Deficiencies in these essential nutrients can potentially accelerate cognitive decline. Some micronutrients that have been identified as vital for brain health include vitamin B12, thiamin, other B vitamins, lutein, magnesium, zinc, and others. The COSMOS trial provides valuable insights into the potential benefits of multivitamins in supporting cognitive health and underscores the significance of nutritional approaches in promoting brain function.
The current trial included 3500 participants aged 60 or older, looking at performance on a web-based memory test. The multivitamin group did significantly better than the placebo group on memory tests and word recall, a finding that was estimated as the equivalent of slowing age-related memory loss by about 3 years. The benefit was first seen at 1 year and was sustained across the 3 years of the trial.
Intriguingly, in both COSMOS and COSMOS-Web, and the earlier COSMOS-Mind study, which was done in collaboration with Wake Forest, the participants with a history of cardiovascular disease showed the greatest benefits from multivitamins, perhaps due to lower nutrient status. But the basis for this finding needs to be explored further.
A few important caveats need to be emphasized. First, multivitamins and other dietary supplements will never be a substitute for a healthy diet and healthy lifestyle, and should not distract from those goals. But multivitamins may have a role as a complementary strategy. Another caveat is that the randomized trials tested recommended dietary allowances and not megadoses of these micronutrients. In fact, randomized trials of high doses of isolated micronutrients have not clearly shown cognitive benefits, and this suggests that more is not necessarily better, and may be worse. High doses also may be associated with toxicity or they may interfere with absorption or bioavailability of other nutrients.
In COSMOS, over the average 3.6 years of follow-up and in the earlier Physicians’ Health Study II, over 1 year of supplementation, multivitamins were found to be safe without any clear risks or safety concerns. A further caveat is that although Centrum Silver was tested in this trial, we would not expect that this is a brand-specific benefit, and other high-quality multivitamin brands would be expected to confer similar benefits. Of course, it’s important to check bottles for quality-control documentation such as the seals of the US Pharmacopeia, National Science Foundation, ConsumerLab.com, and other auditors.
Overall, the finding that a daily multivitamin improved memory and slowed cognitive decline in two separate COSMOS randomized trials is exciting, suggesting that multivitamin supplementation holds promise as a safe, accessible, and affordable approach to protecting cognitive health in older adults. Further research will be needed to understand who is most likely to benefit and the biological mechanisms involved. Expert committees will have to look at the research and decide whether any changes in guidelines are indicated in the future.