Dietary supplements (vitamins, minerals, botanicals, and probiotics) are more popular than ever. More than three-quarters of Americans take at least one, according to the Food and Drug Administration.
Are any of them worth it? The research is mixed. Some vitamins, including multivitamins, have been shown to be beneficial in large randomized clinical trials. Others have been shown to cause harm. Many fall somewhere in between.
The FDA estimates that up to 100,000 different supplement products are sold in stores and online in the United States. They range from multivitamins to herbs and concoctions that promise weight loss, including some that may be toxic or falsely claim to improve brain function.
Robert F. Kennedy Jr., President-elect Donald Trump’s pick for health secretary, told podcaster Lex Fridman in 2023 that he takes “a ton of vitamins and nutrients,” which he said he couldn’t list because he “couldn’t remember.” . all of them.” In an October post on X, Kennedy accused the FDA of “aggressive suppression” of vitamins and nutraceuticals, among other things.
In fact, the FDA has limited oversight over supplements once they are on the market. In a study published in 2018, researchers from the California Department of Public Health raised concerns about products containing unapproved and potentially unsafe ingredients.
The Dietary Supplement Health and Education Act of 1994 placed dietary supplements in the same category as foods according to the FDA. This framework means that the agency regulates dietary supplements as food products rather than pharmaceutical products. As a result, oversight of the safety and effectiveness of products is largely left to the companies that sell them.
“The FDA does not approve dietary supplements or the labeling of their products before they are sold to the public,” Dr. Cara Welch, director of the FDA’s Office of Dietary Supplement Programs at the Center for Safety, said in an interview. Food and Applied Nutrition. the agency’s website. “In fact, most products can be legally marketed without the FDA knowing.”
If a company wants to sell a dietary supplement that contains an ingredient that is not already present in foods sold in the U.S., the company must submit a “new dietary ingredient” notification to the FDA that includes a “history of use.” or other evidence of security.” establishing that the dietary ingredient, when used under the conditions recommended or suggested in the labeling of the dietary supplement, is reasonably expected to be safe.”
The FDA reviews notifications for safety issues, but does not approve or reject the supplement based on the effectiveness of the ingredient.
“Only a small fraction of the dietary supplements on the market have been rigorously tested for effectiveness or safety,” said Dr. JoAnn Manson, chief of the division of preventive medicine at Brigham and Women’s Hospital.
Companies can also use a loophole called generally recognized as secure or GRAS. This designation allows substances considered safe, either because of research or because they are already used in foods, to be used in new products. No notification to the FDA is required.
“Companies can just declare something like GRAS and then add it to supplements, and the FDA will never know about it unless there’s a major problem,” said Jensen Jose, regulatory counsel at the Center for Science in the Public Interest, a nonprofit organization. for-profit for consumers. defense group.
Limits to research.
Many of the vitamins and minerals on the market are generally safe, although not always effective, and the agency has the authority to request a recall if a product causes adverse side effects once consumers start using it or if they discover the company making misleading claims. about a supplement. Some companies also voluntarily self-regulate.
“What we do in self-regulation goes beyond what federal regulation requires,” said Steve Mister, president and CEO of the Council for Responsible Nutrition, a trade association and lobbying group that represents companies that make supplements. “There is a collective mindset that the industry needs to behave responsibly.”
When it comes to research, understanding the effects supplements have on human health is difficult, time-consuming and expensive, said Dr. David Seres, director of medical nutrition at the Institute of Human Nutrition at the University of California Medical Center. Columbia.
“Most of the research you hear about is observational, where two things are correlated but cause and effect cannot be established based on that research,” Seres said. “Most nutrition research tends to be these types of studies.”
“There are clearly supplements with established benefits,” said Christopher Gardner, a nutrition professor at Stanford University. “There are also many supplements that are probably not beneficial, but not harmful either.”
More does not mean better
Manson, who led the COSMOS-Mind clinical trial on multivitamins, said people should be careful with vitamins that contain “megadoses.”
“You have to look at the level and see what it says in terms of percentage of daily intake. It often says 400% or 500%, well above the daily intake value,” he said.
Doses this high can be dangerous or a waste of money.
The U.S. Preventive Services Task Force, an independent panel of medical experts who make preventive and primary care recommendations, just drafted a new recommendation that advises against taking vitamin D to prevent falls and fractures among older adults, based on on evidence showing that it is not beneficial, unless someone has a diagnosed deficiency.
There is some evidence that a daily multivitamin may protect against memory loss; However, numerous studies have failed to demonstrate that supplements have miraculous effects on health. Research like the Mediterranean, which is full of plants, vegetables and fatty fish, can reduce the risks of dementia or heart disease, but supplements generally do not offer the same benefits, according to research.
“In general, we should be able to get all the nutrients we need from food, but the reality is that many people don’t always have access to a reasonable variety of healthy foods,” Gardner said, adding that people who don’t have access to a A variety of nutritious foods may benefit from some supplements.
For everyone else, more does not mean better.
“Most Americans meet all of their vitamin, mineral and nutrient needs. If the intake is already adequate, it is rare that more helps,” he added.
There is no single answer as to why people take supplements that may provide little or no benefit, but it may be due to a strong desire to control their health, Seres said.
“The implication of a benefit is a strong temptation when it is assumed that it cannot be harmful and the airwaves are full of ‘XYZ health endorsements,'” he said.
