Millions of people take a multivitamin each day. Some believe it’s a sort of insurance in case their diet is missing some essential nutrient. Others believe it will ward off disease by boosting immunity, improving brain health, or regulating metabolism. It's easy to see where these ideas come from: ads tout wide-ranging health benefits, even though most offer little or no evidence to back up the claims.

But research on the health benefits of multivitamins has been mixed at best. Last year, for example, the U.S. Preventive Services Task Force, a leading authority on preventive healthcare, reviewed 90 of the best available studies on supplements and vitamins, concluding the products didn’t protect healthy adults lacking nutritional deficits against cardiovascular disease, cancer, or death from all causes.

Might research on different doses, supplement combinations, or populations prompt a different conclusion? Well, yes — in fact, that may have already happened, according to a new study that focused on memory and brain function.

Can a daily multivitamin improve brain function in older adults?

Our current options for improving brain health are limited. For example, regular exercise, optimal weight, and a heart-healthy diet can improve cardiovascular health and lower the chances of certain types of dementia, such as dementia due to strokes. Beyond such common-sense measures, no available medicines, supplements, or treatments reliably improve brain function over the long term, despite advertisements claiming otherwise.

That’s why researchers continue to explore whether certain foods or supplements could prove effective. In a recent study published in Alzheimer’s and Dementia, more than 2,200 volunteers ages 65 and older were randomly assigned to receive cocoa or a placebo, a multivitamin or a placebo, or both cocoa and a multivitamin for three years. The multivitamin chosen for this study was Centrum Silver, which contains 27 vitamins, minerals, and other nutrients in various amounts.

When tests of cognition were analyzed at the end of the trial, those receiving cocoa did not demonstrate any improvement. But those assigned to take a multivitamin had improved scores on tests of:

Based on these findings, the researchers estimated that three years of multivitamin use could slow age-related decline in brain function by as much as 60%.

Notably, study participants were mostly white (89%), had an average age of 73, and more than half were female (60%). They were followed for only three years. However, it was a randomized, double-blind trial, which is considered the most powerful study design.

Should we all be taking multivitamins?

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