by a new study reported that adults aged 60 and older who took a daily multivitamin for two years scored higher on cognitive and memory tests than those who took a placebo, a rare example of a clinical trial that found that a nutritional supplement could actually benefit healthy people.
“It suggests that multivitamins may be a safe, affordable and accessible approach to protecting cognitive health in older adults,” said Dr. Chirag Vyas, a psychiatric epidemiologist at Mass General Brigham in Boston and lead author of the study, published Thursday in The American Journal of Clinical Nutrition.
But experts not involved in the trial cautioned that the benefits were small and it was unclear whether they would translate into tangible improvements in people’s lives.
“I would put it in the realm of promising, but I wouldn’t go to the bank on it,” said Mary Butler, an associate professor of public health at the University of Minnesota, who has published several papers evaluating interventions to prevent dementia.
The research was part of a larger trial involving more than 21,000 older adults looking at whether supplements can protect against several age-related diseases, called the Cocoa and Multivitamin Supplement Outcomes Study (COSMOS). The new report included results from a subset of 573 participants (mostly white and relatively well-educated) who took several in-person cognitive tests.
People in both the multivitamin and placebo groups improved their cognitive scores over two years, possibly because they were already familiar with the tests. But participants who took the multivitamin showed a slightly greater gain, with the biggest increase coming in memory assessments.
The study also combined those findings with results from two previous COSMOS investigations that tested the cognition of more than 5,000 people over the phone or online. In all three studies, those who took multivitamins had consistent improvement in their scores on tests of memory and general cognitive ability compared with people who received a placebo, said Dr. JoAnn Manson, a professor of medicine at Harvard University. and co-director. trial investigator.
The researchers estimated that the memory gains seen in people taking the multivitamin corresponded to a two-year reduction in brain aging, meaning they theoretically performed as well as someone two years younger. said Dr. Vyas.
Experts who were not involved in the research said the study was well designed: It included a large number of participants and used authoritative cognitive tests. But the findings “are relatively modest,” said Dr. Hussein Yassine, an associate professor of neurology at the University of Southern California’s Keck School of Medicine. Although some people may have actually benefited from the multivitamin, he said, most likely did not.
Dr. Yassine added that claiming that a multivitamin could slow cognitive aging by two years “is really a stretch.” To reach that conclusion, the researchers compared the performance of the multivitamin group with the average test scores by age. Dr. Yassine took issue with that technique, calling the interpretation “misleading.”
That calculation was also the top concern cited by Dr. Pieter Cohen, an internist at Cambridge Health Alliance in Boston who studies supplements. He added that it was unclear whether the subtle improvements measured in people taking multivitamins would be significant. It would be much more convincing if the trial found that people who took multivitamins were less likely to be diagnosed with Alzheimer’s at a certain age, or were able to live independently for longer, he said.
Dr. Manson agreed that more research was needed on multivitamins, especially in groups with greater racial, ethnic and socioeconomic diversity. Follow-up studies should look at who benefited from the supplements and why, Dr. Yassine added. It’s possible, for example, that the increases were driven by people who previously didn’t consume enough nutrients important for brain health, such as vitamin B12, vitamin D and zinc.
“Rather than concluding that everyone should take a multivitamin, I think we should possibly try to understand who benefits from taking it,” Dr. Yassine said.
Multivitamins may be helpful for certain people, such as those with conditions that affect their ability to absorb nutrients, Dr. Cohen said, but most healthy people don’t need them. “I’m not going to recommend multivitamins to improve memory based on this data,” he said.
The COSMOS study, funded by the National Institutes of Health and chocolate maker Mars Inc., was originally designed to see whether multivitamins or supplements containing cocoa flavanols would affect heart disease or cancer risk. But the trial found little benefit from either supplement.
Other studies have largely shown that multivitamins did not improve cognition or prevent dementia. For example, in a trial of almost 6,000 male doctors Followed for 12 years, those who took a multivitamin did not do better on cognitive or memory tests than those who took a placebo.
However, research has consistently found that a healthy diet and other lifestyle interventions can benefit the brain. Puja Agarwal, a nutritional epidemiologist at Rush University Medical Center in Chicago, called the new findings “encouraging.” But, she added, “if we can meet our nutritional needs with dietary approaches, that should be the first priority.”
