New COSMOS ancillary study finds that multivitamin supplementation may support episodic memory

A randomized clinical trial published on May 24^th, 2023 in the American Journal of Clinical Nutrition showed that daily oral multivitamin supplements significantly improved participants' memory compared to placebos. In addition, participants with a history of cardiovascular disease may have more significant cognitive benefits from supplementing multivitamins. The research paper emphasizes that compound vitamin supplements have high accessibility and fewer adverse reactions, making them potentially effective strategies for health interventions in the elderly population. 

Previous large-scale and long-term randomized trials have not yielded consistent analysis results on the impact of multivitamins on cognitive function. Evidence from partial meta-analysis suggests that multivitamins can help improve short-term speech memory ability; Other meta-analysis studies have shown that multivitamins have no effect on cognitive function changes. 

The recently completed COSMOS study is a 2 × In a factorial trial, 21442 elderly female and male participants were included in this study, and the effects of dietary flavanols and multivitamin supplements on cardiovascular disease and cancer incidence were evaluated through a 3.6 year follow-up. The COSMOS study includes two cognitive assistance studies (the COSMOS Mind study and the COSMOS Web study). Among them, the analysis results of the COSMOS-Mind study (involving a total of 2262 participants) showed that compared to placebo, supplementing with multiple vitamins can bring overall cognitive benefits, and this effect is more significant among participants with a history of cardiovascular disease. 

Another cognitive assistant study, COSMOS-Web study, aims to evaluate the impact of dietary flavanols and multivitamins intervention on cognitive function mediated by the hippocampus (mainly responsible for the storage and conversion of short-term memory) of the elderly population for one year. This paper reports the analysis results of COSMOS-Web study.

The COSMOS Web study included a total of 3562 elderly participants aged ≥ 60 years (with an average age of 71 years). Participants were randomly assigned to take daily multivitamin supplements or placebos and undergo a series of neuropsychological tests and evaluations annually for a total of 3 years. The main outcome measure of the study was the change in participants' situational memory ability after one year of intervention. Secondary endpoint indicators include: changes in participants' situational memory ability during a 3-year follow-up period; Changes in performance of neuropsychological tasks (including new object recognition, execution ability, etc.) during a 3-year follow-up period.

The analysis results showed that compared with the placebo group participants, participants who took daily multivitamin supplements significantly improved their short-term memory after 1 year (P=0.025), reaching the main endpoint of the study. Moreover, participants who took daily multivitamin supplements during the 3-year follow-up period also showed significantly better short-term memory assessment results (P=0.011), indicating that the memory improvement brought about by multivitamins can be maintained for a long time.

The cross-sectional analysis based on the correlation between age and short-term memory performance further suggests that the improvement effect of multivitamins compared to placebo in memory is equivalent to delaying 3.1 years of age-related memory decline. Interestingly, similar to the previously published conclusions of the COSMOS Mind study, the analysis results of the COSMOS Web study also indicate that participants with a history of cardiovascular disease may have more significant cognitive benefits from supplementing multivitamins.

Overall, the analysis results of this current study indicate that daily supplementation with multivitamins can help maintain or enhance cognitive function in the elderly population compared to placebo. Both the COSMOS Web study and the previously published COSMOS Mind study confirm that participants who take multivitamins have improved memory function. Therefore, supplementing with multiple vitamins is expected to become a safe and highly accessible strategy for maintaining cognitive health in the elderly.