Findings suggest that a daily vitamin supplement may slow cognitive decline in older adults.

A basic, no-frills multivitamin every day may slow cognitive decline by as much as two years, according to a new study published online in the American Journal of Clinical Nutrition.

The findings showed a statistically significant benefit for cognition among participants who took the multivitamin compared with those on the placebo, suggesting that a multivitamin could help prevent memory loss and slow cognitive ageing among older adults, the authors wrote.

Although the findings may be an encouraging signal that warrants further research, 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 (Centrum Silver) not only for their effects on cognitive decline, but also on other conditions such as heart disease and cancer.

So far, the study hasn’t found benefits for any of the studied conditions, according to the authors, with one somewhat unexpected exception: The multivitamin has been 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 Ageing by Two 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.

Not everyone agrees with those conclusions however. Although the study was well-designed and executed, the positive effects were small, meaning that a few people benefited, says Hussein Yassine, MD, an associate professor of neurology and medicine at the Keck School of Medicine at the University of Southern California in Los Angeles. “Future research needs to define who is likely to benefit,” says Dr. Yassine, who was not involved in the research.

The conclusion that the multivitamin could slow cognitive ageing by two years is questionable, says Cohen. To arrive at that estimate, the researchers averaged the results of the tests together and then compared the performance of the multivitamin group with average test scores by age. “I’m not sure that method has ever been used or validated before, so it’s unclear that the differences found here would give the ‘real-life’ slowing of cognitive ageing that the authors suggest,” he says.

To claim a real-world benefit in terms of months or years, there must be a randomised trial with placebo and a multivitamin where people are followed for several years to see if those taking the supplement are less likely to be diagnosed with dementia or are able to live independently for longer, says Cohen.

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 in the U.S.

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.



It Remains Unclear How or Why a Multivitamin Would Preserve Memory or Cognition

It’s important to ponder why a multivitamin might have the benefits suggested here, says Cohen. “What’s the potential mechanism of action for helping with memory or cognition? How does this make sense?”

Multivitamins are the most common dietary supplement taken in the United States; more than 1 in 3 adults report taking one regularly. Centrum Silver, the multivitamin used in the study, contains 24 vitamins and minerals.

Experts Agree: More Evidence Is Needed to Recommend a Daily Multivitamin for Brain Health

All three doctors say it’s too soon to start telling patients to take a multivitamin to preserve cognitive function.

Although these collective findings from three smaller studies within the COSMOS trial add to the evidence for memory benefits from multivitamins, it’s important to note that the group studied here was predominantly white and well-educated, says Baker.

“We do not know about efficacy and safety in underrepresented, minoritised groups that are at higher risk for cardiovascular and other comorbidities. If our goal is to serve the health needs of all people, then we are not ready to make widespread recommendations for daily multivitamin use,” she says. Investigators are planning a new trial that aims to address this issue, she adds.

Cohen agrees that more research is needed to see if the signals suggested here can be confirmed in studies with real-world outcomes. “At this point, I’m not going to recommend multivitamins to my patients as a way to maintain or improve their memory,” he says.

For people who want to preserve their brain health, Yassine recommends daily exercise along with a healthy diet of unprocessed foods rich in fibre, omega-3s, and complex carbs, and low in simple sugars.

“The choice to recommend supplements is better personalised. We still need more research to understand who may benefit from supplements,” he says.

SOURCE: Everyday Health