For years, multivitamins have been dismissed as unnecessary if you eat a healthy diet. New research is making the answer less clear.
Several large randomized trials involving older adults have found that taking a daily multivitamin may provide a modest benefit for memory and overall cognitive function.
The most notable evidence comes from the COSMOS trials. In one study of 3,562 adults, those taking a daily multivitamin performed significantly better on a memory test after one year, with the benefit persisting over three years.
A subsequent analysis combining three COSMOS cognitive studies found benefits in both global cognition and episodic memory. Researchers estimated that the improvement in global cognition was equivalent to about two years less cognitive aging—although that is a statistical comparison, not evidence that a multivitamin literally makes the brain two years younger.
What about Rhonda Patrick?
Researcher Rhonda Patrick has highlighted these findings and argues that a basic multivitamin may be particularly reasonable for adults over 65, partly because nutritional gaps can become more common with age.
But there’s an important distinction between “may help” and “everyone should take one.”
The evidence does not establish that multivitamins prevent Alzheimer’s disease, extend lifespan, or protect against heart disease and cancer.
In fact, the U.S. Preventive Services Task Force says there is currently insufficient evidence to recommend multivitamins for preventing cardiovascular disease or cancer.
And the researchers themselves caution that the cognitive findings don’t necessarily apply to every multivitamin on the market. The COSMOS trials used a specific formulation.
So, should you take one?
For an older adult with a varied, nutritious diet and no nutritional deficiencies, the benefit may be small.
But for someone who eats a restricted diet, has a poor appetite, or may not consistently obtain enough vitamins and minerals, a basic multivitamin could provide useful nutritional insurance.
The takeaway
Multivitamins aren’t a magic pill for aging—but the idea that they are simply useless is becoming harder to defend. The strongest new evidence points to a small potential benefit for cognitive function, while many of the bigger claims made about multivitamins remain unproven.
Food first. Supplements to fill gaps—not to replace a healthy lifestyle.
Evidence & Sources
Evidence: Moderate. Several large randomized trials in older adults found modest cognitive benefits from a daily multivitamin, but the findings come from a specific formulation and do not establish prevention of Alzheimer’s disease, heart disease, or cancer.
- NIH: Daily multivitamin may improve cognition in older adults(opens in a new tab)
- COSMOS-Web: Multivitamin Supplementation Improves Memory in Older Adults: A Randomized Clinical Trial(opens in a new tab)
- COSMOS: Effect of multivitamin-mineral supplementation versus placebo on cognitive function(opens in a new tab)
- U.S. Preventive Services Task Force: Vitamin, Mineral, and Multivitamin Supplementation to Prevent Cardiovascular Disease and Cancer(opens in a new tab)