Findings from a new study show a statistically significant benefit for cognition among participants who took a multivitamin compared with those on the placebo.
A basic, no-frills multivitamin taken every day may slow cognitive decline by as much as two years, according to the study which was published online January 18, 2025 in the American Journal of Clinical Nutrition.
Results also suggest that a multivitamin could help prevent memory loss and slow cognitive ageing among older adults.
Although the findings may be an encouraging signal, it isn’t clear if a multivitamin would stave off cognitive decline or dementia in the real world, says Pieter Cohen, MD, a researcher and internal medicine doctor at Cambridge Health Alliance in Boston, and who was not involved in the trial. “In my opinion, these findings aren’t enough to start recommending that everyone take a multivitamin as a way of maintaining or improving memory,” adds Dr. Cohen.
There’s an Urgent Need for Safe and Affordable Interventions to Protect the Brain
Given the number of people who are affected by dementia and cognitive decline around the world, there’s an urgent need for safe and affordable preventive treatments, says a co-author of the study, Laura D. Baker, PhD, a professor of gerontology and geriatric medicine at Wake Forest University School of Medicine in Winston-Salem, North Carolina.
The search for those solutions inspired COSMOS, or the Cocoa Supplement and Multivitamin Outcomes Study, a nationwide, randomised trial testing cocoa extract and multivitamin supplements not only for their effects on cognitive decline, but also on other conditions such as heart disease and cancer.
Whilst the study didn’t find benefits for all the studied conditions, the exception was that the was associated with a positive effect for cognition.
Latest Study Used In-Person Assessments of Cognition
To participate in COSMOS, women had to be 65 or older, and men had to be 60 or older, and not have a previous history of heart attack, stroke, or cancer (other than skin cancer) diagnosed within two years before the start of the trial.
For this latest study, researchers used detailed in-person cognitive assessments on 573 participants in the subset of COSMOS known as COSMOS-Clinic (the previous two studies used telephone-based and online web-based cognitive assessments).
Investigators observed a “modest” benefit for the multivitamin compared with placebo on overall cognition over two years. There was a statistically significant benefit from multivitamin supplementation on changes in episodic memory, but not in executive function and attention.
These new published findings mark the third report of the positive effects of multivitamins on cognition.
“The fact that similar multivitamin benefits were observed in three different groups of people enrolled in the same parent trial increases our confidence that daily multivitamin supplementation holds promise as a strategy to support cognitive health in older adults,” says Dr. Baker.
A Meta-Analysis Estimated That Vitamins May Slow Cognitive Aging by 2 Years
In a separate meta-analysis based on the three separate studies, with non-overlapping COSMOS participants (ranging from two to three years in treatment duration), researchers found evidence of benefits for both overall cognition and episodic memory.
They estimated that multivitamins slowed overall cognitive ageing by the equivalent of two years compared with a placebo.
The Number of People With Dementia Is Expected to Double by 2050
Dementia is the loss of cognitive function, which includes things like the ability to think, remember, and reason, to the point where it interferes with a person’s daily life, according to the National Institute on Aging.
Recent research suggests that the actual incidence of dementia cases around the globe will continue to climb because people are living longer, along with risk factors that include smoking, obesity, and high blood sugar.
A study published in the Lancet Public Health projected that the number of adults living with some form of dementia in the United States will double by 2050, rising from 5.2 million people to 10.5 million.
SOURCE: Everyday Health
