Dietary supplements are a booming business. More than half of U.S. adults take at least one, and the supplement industry is worth billions of dollars.
But many experts say people are better off saving their money. Regulations on the industry are so lax that supplement makers do not have to prove their products are safe and effective before they hit store shelves—which studies suggest many would have a hard time doing. Plenty of research finds that supplements aren’t all that beneficial for the average person, and may in some cases even be harmful or expose users to dangerous substances.
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The vitamins and minerals in supplements are no match for those found in real food, studies show. “Food contains innumerable other components that are also, ultimately, beneficial for you,” says Dr. Joel Mason, a professor of medicine and nutrition at Tufts University. “It’s better for us, in the long run, to be sustaining our health through a mindfully healthy diet, rather than trying to fill in the gaps” with supplements. Yet many people do just that.
Dr. David Seres, a professor of medicine in the Institute of Human Nutrition at Columbia University Irving Medical Center, wishes they wouldn’t. “Supplementation in the U.S. population, in general, is completely unnecessary,” Seres says. “I would recommend that [users] consider stopping, because it’s a waste of money.”
While Seres does not support widespread supplement use, he and other experts say there are some products that may be helpful on a case-by-case basis. Here’s what to know about supplements that may be beneficial for some people.
Vitamin B12
Vitamin B12, which is found naturally in fish, meat, eggs, and dairy, plays a number of important roles in the body, including supporting nerve cells and aiding the production of DNA. The body’s ability to absorb B12 often declines with age, and some medications commonly taken later in life—including proton pump inhibitors and the diabetes drug metformin—can further compromise absorption. That leaves older adults at risk of B12 deficiency, which in some studies has been linked to an increased risk of dementia, among other problems.
For that reason, Mason says it’s appropriate for older adults, and particularly those taking medications that affect B12 absorption, to consider using a supplement. (Even supplement-shy Seres takes one, a decision he made because he has a B12 deficiency.)
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People who follow a vegan diet, and thus don’t eat animal products that contain B12, likely also benefit from B12 supplementation, Mason says. But aside from those who follow an animal-free diet or have a health condition that affects nutrient absorption, most younger adults get plenty of B12 from their diets. “I don’t think the evidence is there for [supplementation] at every age,” says Dr. JoAnn Manson, chief of preventive medicine at Brigham and Women’s Hospital and a regular researcher of supplements.
Calcium
Calcium’s best-known function is boosting bone health, but it also supports muscles, nerves, blood vessels, and more. It’s found in dairy products as well as some fish, vegetables, and grains.
Older adults, and particularly post-menopausal women, often do not absorb and retain enough calcium from food—particularly because lactose intolerance can develop later in life, causing some seniors to avoid dairy products. Some older adults get enough calcium from their diets, Mason says, but those who don’t may want to consider taking a supplement.
And that goes for men too, he says. “Older men are also prone to osteoporosis,” a condition that leads to weak, breakage-prone bones and is widespread among older women, Mason says. “It’s not as common in men, but it certainly exists.”
That said, older adults shouldn’t exceed 2,000 milligrams of total calcium per day, as too much of the mineral may increase the risk of kidney problems, heart disease, and even prostate cancer, according to the U.S. National Institutes of Health (NIH).
Vitamin D (maybe)
Vitamin D works with calcium to keep bones strong and healthy. It’s also involved in immune and brain function. Only a few foods—including egg yolks, fatty fish, mushrooms, and beef liver—naturally contain vitamin D, but some others, like milk, are fortified with it. The skin can also produce vitamin D via exposure to sunlight.
The skin loses some of that ability with age, however, leaving older adults at particular risk of vitamin D deficiency—a situation compounded by the fact that many seniors don’t spend lots of time outside and may not eat many foods containing vitamin D, Mason says. Starting around age 60, Mason says, some adults may benefit from using a vitamin D supplement.
That’s not a universal opinion. Some experts have urged people not to use vitamin D supplements, given mixed and unconvincing research about their health benefits. The United States Preventive Services Task Force (USPSTF), which issues recommendations about screenings and health habits that may improve well-being, recently published a draft recommendation saying that generally healthy older adults should not take vitamin D—either on its own or in combination with calcium—to prevent falls or bone fractures, because there’s not enough evidence to support that practice.
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What about using vitamin D to combat seasonal affective disorder? Although not all experts agree, Manson says that’s a “very reasonable” move if you’re not getting much sun exposure during the dark winter months. But “no one should ever think of these supplements as cure-alls,” Manson cautions. “Regular physical activity is much closer to a panacea than popping a pill.”
If you do decide to take vitamin D, don’t go overboard. The NIH recommends that most adults consume no more than 100 total micrograms of vitamin D per day. At very high doses, vitamin D may contribute to a range of side effects and complications, including serious ones like kidney failure and irregular heartbeat. Vitamin D supplements can also have problematic interactions with certain common prescription medications, including statins.
Folate and prenatal vitamins
Folate, which is found in fruits, vegetables, legumes, and beef liver, is crucial for cell function and DNA production. Women who are pregnant or considering becoming pregnant should get at least 400 micrograms per day, as the vitamin aids fetal development, according to the U.S. Centers for Disease Control and Prevention. To reach that threshold, people who are pregnant or trying to conceive can take a prenatal vitamin that contains folic acid along with other micronutrients, Manson says.
Just don’t exceed 1,000 micrograms of total daily folate, the NIH says, as high doses can hide or exacerbate B12 deficiency and potentially increase risks of colorectal cancer.
Multivitamins (maybe)
Manson’s research on multivitamins, which contain a cocktail of vitamins and minerals, suggests these popular pills may have significant benefits for older adults. She has published studies suggesting that, at least among adults in midlife or later, multivitamins may be linked to lower cancer risk and slower cognitive aging. “That’s pretty good,” she says, especially for something that’s “safe and doesn’t have all these side effects.”
Not all researchers agree, though. Other studies have found that multivitamins are not linked to reductions in the risk of cancer, heart disease, or mental decline.
Seres says he’s “interested” in the data on multivitamins’ benefits, but not “compelled” by it. He is the nutrition editor for UpToDate, a widely used decision-support tool for health care providers, and notes that the database recommends against healthy people taking multivitamins. The USPSTF has also concluded that there’s not enough evidence to assess the risks and benefits of using multivitamins—or any nutritional supplement—to help prevent cancer or heart disease.
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The bottom line, Seres says, is that most generally healthy people do not need dietary supplements, and particularly not during their younger years. If you have a documented nutrient deficiency or a health concern that may affect your ability to get adequate nutrition from food, discuss with your physician which, if any, supplements are right for you, he says.
But for the most part, your health—and your wallet—will benefit from eating a varied diet that contains plenty of fruits, vegetables, whole grains, legumes, and protein, rather than loading up on pills and capsules.