In 2013, a group of five physicians from the Johns Hopkins School of Public Health and Warwick Medical School in the U.K. made a bold statement:
“We believe that the case is closed—supplementing the diet of well-nourished adults with (most) mineral or vitamin supplements has no clear benefit and might even be harmful. These vitamins should not be used for chronic disease prevention. Enough is enough,” they wrote in an emphatic editorial in Annals of Internal Medicine, one of the most popular medical journals in the US.
Their declaration was based on decades of large-scale studies that found no evidence multivitamins reduced the risk of heart disease or cancer, prevented memory decline, or lowered heart attack rates.
In science, however, the case is almost never truly closed.
This year, a randomized controlled study of more than 3,500 people over the the age of 60 who took multivitamins every day for three years found they performed better on memory tests after a year. After three years, the multivitamin group showed none of the age-related memory decline evidenced by the placebo group.
Does this mean the multivitamin naysayers should start taking vitamin supplements? Who can benefit from them, and who shouldn’t bother?
Vitamins and Memory Loss
Dr. Adam Brickman, a neuropsychologist and a professor at Columbia University, led the study on the impact of multivitamins on cognitive decline in older adults. He found people taking multivitamins (in this case, the study used Centrum Silver vitamins, though Brickman says it’s likely any high-quality multivitamin will replicate the same results) experienced a significant improvement in their memory as compared to those in the placebo group after one year, an effect that was sustained on average over the three years of the study.
“It’s certainly not a panacea for cognitive aging,” Dr. Brickman says, “but it is a reliable effect.”
He pointed out that multivitamins are not a treatment for Alzheimer’s or dementia, and everyone should consult with a doctor before taking any supplements. While this study only included people over the age of 60, some research shows cognitive decline can begin as early as age 45.
A daily multivitamin is a low-cost, low-risk approach for those interested in covering all bases, but this approach should not come at the expense of eating a varied diet full of fruits and vegetables. A large study of more than 30,000 American adults found that while getting adequate amounts of vitamin A, vitamin K, magnesium, zinc, and copper were associated with a lower risk of early death, those benefits were only found when vitamins came through food, not supplements.
“No one is saying that taking vitamins is a replacement for having a healthy diet,” Dr. Brickman says, adding, “This is truly just a supplement that might enhance or bump things up a little bit.”
This means that if you do decide to take a multivitamin supplement to hedge your bets, it’s essential to also prioritize good nutrition, which means filling your plate with whole, unprocessed foods and eating a wide variety of fruits and vegetables, whole grains, and lean protein.
Vitamins for Athletes
While the science isn’t clear about multivitamin supplements for the general population, Melissa Boufounos, a Canada-based certified holistic nutritionist who specializes in sports nutrition, says there are certain instances when a vitamin supplement is highly recommended: folic acid for women trying to conceive and during pregnancy, or with a condition like Crohn’s disease, which makes it difficult for the body to absorb nutrients.
“In some situations like that, a multivitamin could help fill some gaps where the food might not be processed by the body the way it’s supposed to be,” says Boufounos.
If most people don’t need to take a multivitamin, what about athletes—especially endurance athletes who regularly push their bodies to the limit?
Alex Larson is a Minnesota-based registered dietitian who works exclusively with endurance athletes. She says when it comes to nutrition, she always starts with food.
“That’s always the gold standard,” Larson explains, “and a supplement is not a replacement for a balanced diet.”
Larson does recommend her athletes get an annual or semi-annual blood test to find out if they have any vitamin deficiencies, as well as consult with a primary care physician to make sure there aren’t any underlying medical conditions or medications that might conflict with supplements. Many of the female endurance athletes she works with find their iron levels are low, and she recommends an iron supplement—or better yet, iron-rich food—to help with performance and energy levels.
Boufounos agrees, saying she always takes a food-first approach with athletes. She approaches supplementation as a short-term solution to bridge any gaps while trying to correct dietary patterns.
“I never want to tell an athlete that they have to supplement long term because you also get into a situation where I think some people unintentionally rely on the supplement,” says Boufounos.
She especially sees this phenomenon with green powders, which often contain multivitamins.
“I’ve seen so many athletes supplement with a green powder that also had the multivitamin in it and then they’re like ‘Sweet, I don’t need to ever eat a vegetable ever again,’” says Boufounos.
How to Choose Your Multivitamin
If you decide you do want to start taking a multivitamin, Boufounos says it’s important to make sure your supplement meets the recommended dietary allowance (RDA) for as many of the micronutrients as possible. Some supplements have 100 percent of the RDA for only a few vitamins, and the other ones don’t come close to the daily recommendations.
More than price, however, look at what’s included in the multivitamin. Boufounos says it’s not worth paying for extra micronutrients if they are in negligible amounts.
Both Larson and Boufounos say it’s essential to buy supplements that are third-party tested, especially if you’re an athlete in a tested sport, but also to make sure the supplements are safe and contain exactly what the label claims. Supplement companies that are third-party tested will always state that distinction clearly on their website or marketing materials.
Larson also recommends serious athletes who might be tested for their sport take supplements that are labeled NSF Certified for Sport or Informed Choice for Sport.
“I would be very careful about just typing in ‘multivitamin’ on Amazon and buying something because there are most definitely knockoffs on Amazon and that can get sketchy pretty quickly,” Boufounos says. She recommends buying supplements directly from the company’s website, not an online storefront.
If you plan to start taking vitamin supplements without consulting with an expert, Boufounos recommends sticking with a multivitamin, instead of selecting individual vitamins on their own.
“It would be safer for an athlete to use a multivitamin if they’ve never done a blood test and never worked with a dietician or a sports nutritionist than it would be for them to just randomly pick any supplement off the store shelves,” Boufounos says, because you might pick supplements that work against each other.
The science so far is clear about two things: multivitamins appear to help age-related cognitive decline but don’t seem to prevent chronic disease. The best multivitamin strategy—whether you’re an athlete or not—is to focus on food first, supplements second.