It would be nice if popping a pill or two each day was all it took to live longer. Vitamin supplements may offer some people an advantage against certain illnesses, but in general, they’re unlikely to help you live an extra birthday.
A new study has found that multivitamins don’t help people live longer, but other research suggests that they may have health benefits that help people stay healthy in older age.
Researchers from the National Institutes of Health (NIH) pooled data from three large studies that assessed the diet and health of more than 390,000 adults, looking at multivitamin use and health outcomes over a period of nearly three decades.
“Many U.S. adults report using multivitamins to maintain or improve their health,” NIH epidemiologist Ericka Loftfield and her colleagues wrote in the published paper.
But whether the promise of improved health translates into longer life spans is another question. The results of this analysis confirm the largely negative findings of previous studies, suggesting that taking a daily multivitamin does not extend life span.
Conversely, people who took multivitamins had a slightly higher risk of dying from any cause (only 4%) during the first few years of follow-up compared with non-users.
There could be a number of reasons for this that are difficult to understand: For example, people with age-related health problems might be more likely to try multivitamins.
However, people who take multivitamins are more likely to eat healthier, exercise more, smoke less, and earn enough to afford the supplements — all factors that can improve their health.
The same could be said in this study: Although the participants were generally very healthy and had no history of cancer or other chronic diseases, those who used multivitamins tended to eat a higher quality diet and have lower BMI (body mass index) scores, a health screening tool that is often criticized and now discouraged.
These confounding factors, although well taken into account in the study, have obscured previous analyses, and the wide variety of multivitamins available makes it very difficult to compare them across observational studies and clinical trials.
Even before the study’s findings, experts were not enthusiastic about the benefits of taking multivitamins, arguing that the benefits vary depending on who takes them, why and how.
Taking certain vitamins can help those with medically diagnosed deficiencies, such as iron or vitamin B deficiency, or to make up for extra nutritional needs during pregnancy.
Some recent studies have also suggested that taking a daily multivitamin may improve memory and slow cognitive decline, but only in older adults and for short periods of time. Antioxidant vitamins such as vitamin C and zinc also appear to help prevent macular degeneration, a condition that can cause vision loss with age.
However, supplements can be harmful or dangerous if taken in too much, taken with other vitamins, or if they interact with prescription medications.
Beta-carotene supplements may increase the risk of lung cancer in smokers, vitamin K may reduce the effectiveness of blood-thinning drugs, and calcium and zinc limit the absorption of antibiotics used to fight bacterial infections.
And because multivitamins are not regulated in the same way as prescription and over-the-counter drugs, they are open to exaggerated claims that don’t need to be backed up by evidence.
Getting the vitamins you need every day through your diet, rather than taking supplements, is a safer approach for most people. For example, a 2023 study found that switching to a healthier food diet could add up to 10 years to your life.
“The greater the change towards healthier dietary habits, the greater the expected gain in life expectancy,” the team behind the study explained at the time.
But again, the ability to eat healthy depends on who can afford it and how much access they have to nutritious, fresh food options.
This new study JAMA Network Open.
