Daily Multivitamin Use May Slow Memory Decline in Older Adults

Introduction

Recent research conducted by scientists at Harvard University reveals promising evidence that daily intake of multivitamin supplements can help slow down memory decline in older adults. Published in the latest issue of the American Journal of Clinical Nutrition, this study adds to a growing body of evidence supporting nutritional strategies for cognitive health in aging populations.

Background and Study Aim

Aging is often accompanied by gradual cognitive decline, particularly in memory and executive function. With the global population aging rapidly, identifying safe and accessible interventions to maintain cognitive health has become a priority for public health.

The Harvard-led study aimed to investigate whether daily supplementation with multivitamins and/or cocoa extract could prevent cardiovascular disease or cancer in adults aged 60 and older, and whether such supplements also have measurable effects on cognitive function. As part of this broader trial, a subset of participants underwent memory and cognitive testing to assess potential psychological benefits.

Study Design and Methods

The study was part of the COcoa Supplement and Multivitamin Outcomes Study (COSMOS), a large-scale 2 × 2 factorial randomized trial involving 21,442 participants in the United States aged 60 years or older. Participants were randomly assigned to receive either a cocoa extract (500 mg flavanols daily), a daily multivitamin-mineral (MVM) supplement, both, or placebo.

Within COSMOS, three cognitive substudies were conducted:

• COSMOS-Clinic: 573 participants completed in-person cognitive testing at baseline and after two years.
• COSMOS-Mind: 2,158 participants were assessed annually via telephone.
• COSMOS-Web: 2,472 participants completed annual internet-based neuropsychological assessments over three years.

The primary cognitive outcomes included global cognition, episodic memory, executive function, and attention. Memory was assessed using standardized tests such as the ModRey immediate recall test and verbal fluency tasks.

Key Findings

Analysis from the COSMOS-Clinic cohort showed that multivitamin supplementation modestly improved global cognition compared to placebo over two years, with a mean difference equivalent to a 2-year reduction in cognitive aging. Episodic memory improvements were statistically significant, while no notable changes were seen in executive function or attention.

Meta-analysis combining data from all COSMOS cognitive substudies confirmed the cognitive benefits of multivitamin supplementation on global cognition and episodic memory, supporting the robustness of these findings.

Additional studies reinforced these results:

• A 12-week randomized, placebo-controlled trial found that multivitamin supplementation improved mood-related outcomes such as increased friendliness in women and reduced stress reactivity and emotional loneliness in men aged over 70.
• The COSMOS-Web ancillary study showed that daily multivitamin use improved immediate recall memory over one and three years, with effects equivalent to reversing 3.1 years of age-related memory decline.
• The COSMOS-Mind trial further demonstrated that three years of daily MVM supplementation significantly enhanced global cognition, episodic memory, and executive function, particularly in participants with cardiovascular disease history. Conversely, cocoa extract alone did not provide cognitive benefits.

Implications for Older Adults

These findings suggest that regular multivitamin supplementation could serve as a safe, affordable, and accessible strategy to help maintain cognitive health and slow memory decline in older populations.

Although the exact components of multivitamins responsible for these benefits are not yet identified, the overall positive impact on cognition is encouraging. It is important to note that these studies are among the first large-scale randomized clinical trials to demonstrate cognitive benefits from multivitamin use.

Expert Commentary and Future Directions

JoAnn Manson, the study’s lead investigator and a professor at Harvard Medical School, emphasized the significance of slowing cognitive aging by approximately two years, which represents a meaningful advancement in aging research.

However, nutrition experts like Duane Miller, a registered dietitian and senior lecturer at Aston University, caution that the current evidence is preliminary. The original COSMOS trial was not primarily designed to assess memory effects, and more targeted research is necessary to confirm these findings and understand underlying mechanisms.

Future studies should also aim to include more diverse populations to ensure findings are generalizable across different ethnic and socioeconomic groups.

Conclusion

The collective evidence from multiple rigorous studies indicates that daily multivitamin supplementation can modestly improve memory and cognitive function in older adults, potentially delaying the onset of cognitive decline. While more research is warranted, these findings support considering multivitamins as part of a comprehensive approach to healthy aging and cognitive preservation.

References

• Vyas CM, Manson JE, et al. Effect of multivitamin-mineral supplementation versus placebo on cognitive function: results from the COSMOS randomized clinical trial and meta-analysis. Am J Clin Nutr. 2024 Mar;119(3):692-701.
• Docherty S, Wetherell MA, et al. Improvements to mood, stress, and loneliness following 12-week multivitamin supplementation in older adults: a randomized, placebo-controlled trial. Eur J Clin Nutr. 2025 Mar;79(2):126-135.
• Yeung LK, Alschuler DM, et al. Multivitamin Supplementation Improves Memory in Older Adults: A Randomized Clinical Trial. Am J Clin Nutr. 2023 Jul;118(1):273-282.
• Baker LD, Manson JE, et al. Effects of cocoa extract and a multivitamin on cognitive function: A randomized clinical trial. Alzheimers Dement. 2023 Apr;19(4):1308-1319.