Grace Carey / Getty Images
Americans spend billions of dollars on nutritional supplements each year, and one in three adults reports taking a multivitamin. But there is debate as to whether this helps promote good health.
A team of researchers wanted to evaluate how a daily multivitamin affects cognitive aging and memory. They tracked about 3,500 older adults who were enrolled in a randomized controlled trial. One group of participants took a placebo, and another group took Silver Centrum Multivitamin for 3 years. Participants also took online tests to assess memory.
At the end of the first year, people who took a multivitamin showed an improvement in the ability to remember words. Participants were given lists of words, some related to each other, some unrelated, and asked to remember as many words as possible. (Learning list tests assess a person’s ability to store and retrieve information.)
The people who took the multivitamin were able to remember about a quarter of the extra words, which translates to remembering a few more words, compared to the placebo group.
“We estimate that the effect of the vitamin intervention improved memory performance above placebo by the equivalent of 3.1 years of age-related memory change,” the authors write in their paper, which was published this week in the American Journal of Clinical Nutrition. The authors indicate a sustained benefit.
“It’s interesting,” says Dr. Jeffrey Linder, MD, chief of general internal medicine at Northwestern University Feinberg School of Medicine, who was not involved in the study. But he says the overall effect found in the study was very small. “It seems like a very small difference,” says Linder. He notes that the multivitamin had no effect on other areas of cognition assessed in the study such as executive function, which may be more important than the scales.
This is not the first study to show the benefits of a multivitamin, says study author Dr. Joan Manson, MD, chief of preventive medicine at Brigham and Women’s Hospital. She points to a study published last year in Alzheimer’s & Dementia that showed participants who took a daily multivitamin performed better, overall, with regard to global cognitive function, on tests measuring story recall, verbal fluency, and number order, as well as executive function.
“It is surprising that such a clear signal of slowing age-related memory loss and cognitive decline was found in the study,” says Manson. “Those who received the vitamins did better than those who received the placebo.”
Our bodies and brains require many nutrients for optimal health and efficiency. Manson says that if people are deficient in these nutrients, it can affect memory loss or accelerate cognitive decline. Therefore, she says, taking a multivitamin may help someone prevent deficiency, if they are not getting all the nutrients they need from their diet.
“It is important to highlight that a multivitamin will never be a substitute for a healthy diet,” says Manson, “because micronutrients are better absorbed through foods than from supplements.” “Adults,” she says.
Linder says he will continue to tell his patients that if they eat a healthy diet they are not likely to benefit much from a multivitamin. “If you’re taking too much of a certain supplement and your body doesn’t need it, you’re overdoing it,” he says. He wrote an editorial, published in JAMA, in which he said that vitamins and nutritional supplements can be a waste of money for many people. He argues, we should help people adopt a better eating pattern.
“Eating a diet that includes plenty of fruits and vegetables is associated with longevity, improved performance, and an improved quality of life,” says Linder. There’s plenty of research to show that a healthy diet is linked to better heart health, and when it comes to protecting cognitive function, “the current thinking is that all things that are good for your heart are also good for your brain,” he says.
When Linder talks to his patients about healthy aging, he focuses on good sleep habits, physical activity, and a healthy diet. “My big concern with all of people’s focus on vitamins is that it distracts them from things that will actually help them stay healthy,” says Linder.
“If someone takes a multivitamin, I wouldn’t tell them to stop,” says Dr. R. Shawn Morrison, MD, a geriatrician at Mount Sinai Health System in New York. But he says he wouldn’t promote the use of multivitamins as a way to protect against memory loss, because he says the effects measured in studies aren’t entirely convincing. “I don’t think it’s the magic bullet people are looking for,” says Morrison. When talking to his patients, he also emphasizes the importance of healthy habits and good social relationships.
The study was funded in part by the National Institutes of Health and other grants. The vitamins were supplied by Pfizer, Inc. and Haleon, makers of Centrum, the brand of multivitamin that study participants took. The study authors say the funders had “no role” in the design, analysis, or interpretation of the study.