Multivitamins Slow Biological Aging in Large Trial

 This transcript has been edited for clarity. 

This is Dr JoAnn Manson, professor of medicine at Harvard Medical School and Brigham and Women’s Hospital. I’d like to talk with you about a recent study that was presented at the 2025 American Heart Association Epidemiology, Prevention, Lifestyle & Cardiometabolic Health Scientific Sessions that took place in New Orleans earlier this month. This study, the Cocoa Supplement Multivitamins Outcomes Study (COSMOS), addressed whether daily multivitamin supplementation, in a randomized clinical trial setting, could slow biological aging as measured by DNA methylation in epigenetic clocks.

As you know, very few interventions aimed at slowing biological aging have been tested in randomized trials. We also know that many people have deficiencies in one or more micronutrients, and healthy nutrition is very important for optimal health and for the prevention of chronic diseases of aging.

In prior randomized trials, multivitamins have shown benefits for reducing risks of several chronic diseases. For example, both the Physicians Health Study II and the 2022 US Preventive Services Task Force review reported that total invasive cancer was reduced with multivitamin supplementation. Further, multivitamins were also associated with a reduced risk of cataracts in the Physician’s Health Study II and with significantly slower age-related memory loss and cognitive decline in three separate placebo-controlled substudies of the COSMOS trial.

So, it made sense to determine whether a slowing of biological aging could be a contributing factor — or mechanism of — this reduction in chronic disease risk in response to multivitamin supplementation, as observed in these randomized trials.

The COSMOS trial included men and women who were older adults (≥ 60 years of age). In this study, the average age was 70.2 years. I’d like to acknowledge that I’m a co-investigator on this study. Approximately 950 participants who had blood tests at baseline and at 1-year and 2-year follow-ups were randomly selected. Biological aging was assessed using five different epigenetic clocks, two of which were first-generation, two were second-generation, and one was DunedinPACE. 

In all five epigenetic clocks, there was a signal for slower aging in the multivitamin compared with the placebo arm. For the two second-generation clocks (PCGrimAge and PCPhenoAge), there was significant slowing of biological aging in the multivitamin arm compared with the placebo arm, with an average of about 10%-20% slower aging with daily multivitamin use over the 2 years of the intervention. This equated to about 4 months of aging that seemed to be averted or prevented. Among participants who had accelerated aging at baseline, the reported benefits were even greater. 

Now, we clearly need replication of these findings, and multivitamins and other dietary supplements will never be a substitute for a healthy diet and healthy lifestyle. But these findings are promising and suggest that guidelines committees may want to look at the results of these randomized trials and mechanistic studies to decide whether recommendations should be made for the use of multivitamins (as a complement to a healthy diet and lifestyle) in the prevention of chronic diseases of aging.

https://www.medscape.com/viewarticle/multivitamins-slow-biological-aging-large-trial-2025a10006u7