FFrom multivitamins and melatonin to fiber and fish oil, Americans trying to improve their health and immunity have a plethora of supplements to choose from. An estimated 58% of American adults over the age of 20 take dietary supplements, according to the US Centers for Disease Control and Prevention, and the supplement industry is valued at more than $30 billion a year. The use of supplements has grown rapidly in recent decades along with the wellness industry.
“The popular belief is that a supplement is going to be helpful in promoting health,” says Fang Fang Zhang, a professor in Tufts University’s Friedman School of Nutrition Science and Policy. She has found that people who use supplements more often are also more likely to have a higher level of education and income, a healthier lifestyle, and a greater chance of eating a healthy diet and exercising. “So those who take supplements are more health conscious in general,” she says.
But if you’re already in good health, most supplements may not do much to improve your health or stave off death. “There is no clear evidence to suggest benefits of dietary supplement use for many popular or common health outcomes,” says Zhang.
In some cases, the use of supplements could even be harmful. 2015 study published in the New England Journal of Medicine found that there are an estimated 23,000 emergency department visits each year in the US for adverse events related to dietary supplement use, many related to cardiovascular problems from weight loss or energy products. “Particularly when we use very high-dose deployments, we can sometimes be doing more harm than good,” says Eliseo Guallar, a professor of epidemiology and medicine at the Johns Hopkins Bloomberg School of Public Health.
Some experts have called for stricter federal regulation to ensure supplements are safe and effective. Until then, consumers may want to proceed with caution and do their due diligence before taking supplements.
What are supplements for?
Vitamins, minerals and many other micronutrients are vital to the functioning of the body and are a crucial part of a good diet. But it is not the same to ingest nutrients in food than to take them in supplement form. “The use of dietary supplements is not a substitute for a healthy and balanced diet,” says Zhang.
Vitamin and mineral supplements can be extremely helpful when prescribed for people with nutritional deficiencies and certain illnesses. “High-quality supplements need to be widely available, and we need them as part of medical treatment,” says Dr. Pieter Cohen, an associate professor at Harvard Medical School and an internist at Cambridge Health Alliance.
However, much of the packaged food in the US is already fortified with additional nutrients, making nutritional deficiencies rare in the general population. For most people, supplements may offer questionable benefit.
in a analysis published in 2020 in the BMJZhang reviewed the results of several trials and found no clear evidence that nutritional supplements, such as vitamins and minerals, are helpful in healthy people in preventing chronic diseases such as cardiovascular disease or cancer.
The evidence is even more confusing for certain plant-derived dietary supplements known as botanicals, such as echinacea and ginkgo. Scientists have tried to decipher the effects of many botanicals or nutritional supplements, but the field is still plagued by weak or conflicting results. “We know a lot,” says Guallar. “The problem is that sometimes the claims go beyond what we know.”
Many of the health claims that companies place on their supplement labels may extrapolate results seen in animals to humans or overemphasize what are still preliminary findings. “These products should not be promoted as having benefits for our health when they have never been proven to work in humans,” says Cohen.
As a result, consumers may not know what to make of supplement claims and may be confused about which supplements are helpful. “This is also combined with commercial pressure to promote some of these supplements,” says Guallar.
How dietary supplements are promoted and advertised is itself a function of how they are regulated by the US Food and Drug Administration (FDA).
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Regulated as food, not drugs
Although many people take supplements because they want to improve their health, the FDA does not regulate them as drugs but as foods, under the Health and Dietary Supplement Education Act of 1994.
“What happened in 1994 was that all these products, from vitamins, minerals and botanical extracts, became subcategories of foods,” explains Cohen. “It also created a completely different structure in terms of advertising, like the ability to advertise products to say things like ‘This will boost your immune system,’ as code for ‘This will prevent infection,’” he says.
Manufacturers are not required to prove that their supplements are effective or safe before marketing them. And supplements aren’t held to the same manufacturing standards as drugs, which can lead to substandard or adulterated products. “It’s basically very difficult, if not impossible, to separate the poor quality products from the higher quality products on the market, at least at the moment,” says Cohen.
Part of issue it’s that the current system doesn’t do a good job of tracking when supplements cause harm, says Cohen. “I think we need to realize that for the public to have access to high-quality vitamins, minerals and botanicals, we’re going to need to reform the law,” he says.
Cohen has suggested changes to current regulations, including standardizing manufacturing processes, carefully researching new ingredients, and creating higher standards for the claims manufacturers can make about their supplements.
But for now, consumers can keep a few things in mind when deciding whether to take supplements.
Navigating the supplement aisle
When evaluating supplements, beware of outlandish claims as they are unlikely to be true. Also keep in mind that some supplements may contain a much higher dose in a single pill or serving than you need. “Sometimes these supplements are promoted in doses that are much higher than what you would get from diet,” says Guallar.
In general, consult your doctor about the use of any supplement, as many supplements can interact with medications you are taking. They may also not be safe to take during pregnancy or breastfeeding, before surgery, or during cancer or other medical treatments.
Consumers must also know how to spot poor quality products. “My general advice to patients is to stick to supplements that list just one ingredient and avoid a mix of things, with the exception of multivitamins,” says Cohen. He cites certain certifications, such as USP either NSF Internationalas a sample of higher quality products.
Beware of weight loss supplements, muscle builders, and sexual enhancers, which are previously research found are sometimes adulterated with illegal or hidden ingredients, such as pharmaceutical drugs and synthetic chemicals. These types of supplements may be particularly likely to contain these undisclosed ingredients.
Finally, consumers can search for information on specific vitamins, minerals, and botanicals on reputable sites. websitesincluding those led by Memorial Sloan-Kettering Cancer Center and the National Institutes of Health.
The bottom line
“We don’t eat just one nutrient; we eat a food,” says Zhang. “That’s why many supplements don’t achieve the same effect as natural nutrients from food sources,” she says.
Zhang points out that the scientific evidence could always evolve as researchers continue to study nutritional supplements. But for now, there are more reliable ways to improve health. “The use of dietary supplements should not be a substitute for a healthy diet and lifestyle,” says Zhang. “There is no magic pill, unfortunately.”
The truth about popular supplements
It is generally considered useful
Folic Acid During Pregnancy: Folic acid supplementation during pregnancy is well established to help prevent birth defects. “That is considered a success story,” says Guallar.
Fiber: Fiber supplements like psyllium can help reduce constipation, prevent heart disease, and decrease cholesterol—although getting fiber from your diet also provides the vitamins and micronutrients found in whole foods.
Melatonin: It can help with jet lag. However, the evidence that it helps with insomnia or sleep disorders is not particularly strong.
Calcium and vitamin D after menopause: Postmenopausal women may benefit from taking calcium and vitamin D supplements to prevent bone loss.
A blend of supplements for adults with age-related macular degeneration: A combination of zinc, vitamins C and E, copper, lutein, and zeaxanthin may help slow vision loss in people with this eye disease.
Mixed evidence or no evidence to help
Multivitamins: They are extremely common—about a third of American adults take them—but there is no clear evidence that they help reduce mortality or prevent major chronic diseases, such as cancer or heart disease, in healthy people. But experts say multivitamins probably won’t hurt either.
Echinacea: It may slightly reduce the chances of getting a cold, but the evidence is weak and there is little evidence that it helps treat colds or respiratory infections.
Ginkgo biloba: Studies have found that this supplement does not appear to improve cognitive performance or prevent Alzheimer’s disease or dementia.
Glucosamine and chondroitin: There is conflicting evidence that they help relieve symptoms of osteoarthritis.
Vitamin D: Despite great interest in its many potential health benefits, it remains unclear whether vitamin D supplements do much for healthy people. And in people who don’t have a deficiency, Zhang found that very high doses of vitamin D can increase the risk of all-cause and cancer mortality.
Antioxidants: Composed of vitamins A, C, and E, as well as selenium, beta-carotene, and folate, antioxidants have been touted as having numerous health benefits, but so far they haven’t lived up to the hype. They don’t seem to protect against heart disease, stroke, or cancer, and some can be harmful in high doses.
Omega-3 fatty acidsEating foods rich in omega-3 fatty acids, such as fish, has been shown to protect against heart disease, but it is not yet clear whether they offer the same protection when consumed in supplement form. Some studies indicate that they may help protect against certain heart conditions, while others did not show any benefit.
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