‘Any benefit likely to be small’
In an editorial accompanying the publication of the USPSTF statement, Jenny Jia, MD; Natalie Cameron, MD; and Jeffrey Linder, MD – all from Northwestern University, Chicago – noted that the current evidence base includes 52 additional studies not available when the last USPSTF recommendation on this topic was published in 2014.
The editorialists pointed out that for multivitamins, proving the absence of a benefit is challenging, but at best, current evidence suggests that any potential benefits of a multivitamin to reduce mortality are likely to be small.
They gave an example of a healthy 65-year-old woman with a 9-year estimated mortality risk of about 8%, and note that taking a multivitamin for 5-10 years might reduce her estimated mortality risk to 7.5% (based on an odds ratio of 0.94).
“In addition to showing small potential benefit, this estimate is based on imperfect evidence, is imprecise, and is highly sensitive to how the data are interpreted and analyzed,” they said.
The editorialists recommended that lifestyle counseling to prevent chronic diseases should continue to focus on evidence-based approaches, including balanced diets that are high in fruits and vegetables and physical activity.
However, they added that healthy eating can be a challenge when the American industrialized food system does not prioritize health, and healthy foods tend to be more expensive, leading to access problems and food insecurity.
The editorialists suggested that, rather than focusing money, time, and attention on supplements, it would be better to emphasize lower-risk, higher-benefit activities, such as getting exercise, maintaining a healthy weight, and avoiding smoking, in addition to following a healthful diet.
Possible benefit for older adults?
Commenting on the USPSTF statement, JoAnn Manson, MD, chief, division of preventive medicine, Brigham and Women’s Hospital, Boston, who led the recent COSMOS study, said that vitamin and mineral supplements should not be perceived as a substitute for a healthful diet.
“The emphasis needs to be on getting nutritional needs from a healthy diet that is high in plant-based and whole foods that don’t strip the vitamins and minerals through excessive processing,” she said. “Although it’s easier to pop a pill each day than to focus on healthful dietary patterns, the mixture of phytochemicals, fiber, and all the other nutrients in actual foods just can’t be packaged into a pill. Also, vitamins and minerals tend to be better absorbed from food than from supplements and healthy foods can replace calories from less healthy foods, such as red meat and processed foods.”
However, Dr. Manson noted that the evidence is mounting that taking a tablet containing moderate doses of a wide range of vitamins and minerals is safe and may actually have benefits for some people.
She pointed out that the COSMOS and COSMOS-Mind studies showed benefits of multivitamins in slowing cognitive decline in older adults, but the findings need to be replicated.
“The USPSTF did see a statistically significant 7% reduction in cancer with multivitamins in their meta-analysis of four randomized trials and a borderline 6% reduction in all-cause mortality,” she noted. “Plus, multivitamins have been shown to be quite safe in several large and long-term randomized trials. I agree the evidence is not sufficient to make a blanket recommendation for everyone to take multivitamins, but the evidence is mounting that this would be a prudent approach for many older adults,” Dr. Manson said.
“Many people view multivitamins as a form of insurance, as a way to hedge their bets,” she added. “Although this is a rational approach, especially for those who have concerns about the adequacy of their diet, it’s important that this mindset not lead to complacency about following healthy lifestyle practices, including healthy eating, regular physical activity, not smoking, making sure that blood pressure and cholesterol levels are well controlled, and many other practices that critically important for health but are more challenging than simply popping a pill each day.”
A version of this article first appeared on Medscape.com.