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Could a daily multivitamin help slow cognitive decline?

Results from a clinical trial suggest a multivitamin could help, but researchers say the findings need to be confirmed with additional studies.
Image:  Multivitamins
Participants in the trial took a multivitamin, a cocoa extract supplement or a placebo.Yulia Reznikov / Getty Images

Early findings from a clinical trial suggest that taking a daily multivitamin may delay cognitive decline in older adults. 

The results, presented Wednesday at the Clinical Trials on Alzheimer’s Disease conference in Boston, are currently under review and have not yet been published in a peer-reviewed journal. A number of questions remain as to how big of a role supplementation may play, but Laura Baker, a professor of gerontology and geriatric medicine at Wake Forest School of Medicine, who led the trial, said if further research confirms the findings, multivitamins could fill a gap in preventive care. 

“I am always looking for something that is inexpensive and accessible to everyone, especially to communities that don’t have access to expensive interventions,” Baker said. “It’s already such a widely used supplement and we need to know if it might have any benefits for cognitive function.” 

The new research revisits the question of whether a daily multivitamin has health benefits; a previous large clinical trial in men found that taking a multivitamin did not appear to improve cognitive functioning. 

The COSMOS-Mind clinical trial included more than 2,200 people ages 65 and older who did not show any signs of Alzheimer’s disease or dementia when they enrolled. The participants were part of a larger clinical trial, called the COSMOS trial, that looked at the effects of both multivitamins (in this case, Centrum Silver) and cocoa extract supplements on cardiovascular disease and cancer. 

Pfizer, the company that makes Centrum Silver, provided some of the vitamins used in the trial, and Mars Inc., the candy and snack maker, partially funded the parent study. Neither company had any part in designing either trial. 

Participants were evaluated at the beginning of the study before being blindly prescribed either a daily placebo, a multivitamin, a cocoa extract supplement or both a cocoa extract supplement and multivitamin. Once a year for three years, the participants underwent a series of tests that evaluated their overall cognitive function, memory and executive function. 

Those who took a daily multivitamin showed a statistically significant improvement in memory and executive function associated with normal and pathological aging, including Alzheimer’s disease, compared to the placebo group in the first two years of the study, the researchers found. After that, the benefits plateaued. No benefits were observed in the group taking the cocoa supplement. The multivitamin appeared to slow cognitive decline by about 60 percent, or the equivalent of 1.8 years. 

“Especially when you’re talking about vitamins or food, you’re going to see a level of improvement but there is only so far you’re going to go. I would anticipate improvement right up front and maintenance after that, which is still incredible,” said Thomas Shea, director of the Laboratory for Neuroscience at UMass Lowell, who was not involved with the trial. 

Around 10 percent of participants, or about 200 people, had heart disease when they started the trial, which is linked to an increased risk of cognitive decline. At baseline, they scored lower than average. Those who got a multivitamin improved quite a bit, putting them on par with improvements seen in those who did not start with heart disease. But those who got the placebo continued to decline after the first year, Baker reported during Wednesday’s presentation.

The findings suggest that the multivitamin could provide some “additional cognitive resilience” that helps work against cardiovascular disease-related cognitive decline, Baker said. “That’s exciting because we don’t have treatments right now that can correct it, but it’s a preliminary finding and we need to replicate it.”

Baker isn’t ready to recommend a multivitamin to ward off cognitive decline quite yet. One reason is that trial participants were almost 90 percent white, which does not reflect the general population. 

The results also contradict the findings of a previous randomized, double-blind, placebo-controlled trial that ran from 1997 to 2011. That study, called the Physicians’ Health Study II, included almost 6,000 male physicians who were 65 or older and found that a daily multivitamin did not have a significant impact on cognitive impairment. Caveats to that study include that the researchers did not take a baseline measurement, which gives scientists a point of comparison for later results, and the study only included male physicians, rather than people of all sexes and backgrounds. The two trials used different formulas of multivitamin, which means a certain ingredient may have been responsible for improvements rather than the vitamin as whole.

“If we have two trials that show a positive outcome and one that shows the intervention didn’t have an effect, then I’ll feel confident,” Baker said. “But right now we just have a one-to-one, and I don’t want to lead people astray if we’re wrong.”  

According to Dr. Domenico Praticò, director of the Alzheimer’s Center at Temple University in Philadelphia, certain vitamin deficiencies, including vitamins B6, B12 and E, have been linked to memory loss.

Still, Praticò urged caution in interpreting the results.

“I don’t want to give the false message that multivitamins are the golden ticket for good memory. I would only recommend a multivitamin if my patient has a deficit of certain vitamins in the blood,” he said. 

Eating a balanced diet and keeping physically and socially active are important interventions that help keep aging brains healthy, and can’t be replaced by a vitamin, Shea said.

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