Many dietary supplements contain unlabeled and even potentially dangerous ingredients, but government oversight on these products remains limited, writes Christie Aschwanden for the Washington Post.

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The hidden, extra ingredients in dietary supplements

Aschwanden reports that while many people buy dietary supplements believing that that are safer or more "natural" than pharmaceuticals. But supplements may contain hidden—and sometimes dangerous—ingredients.

For instance, in a recent study in Clinical Toxicology, Pieter Cohen, a physician at Cambridge Health Alliance and associate professor at Harvard Medical School, along with other researchers, found 9 prohibited stimulants in 17 brands of sports and weight-loss supplements. Almost half of the tested supplements contained more than one stimulant.

Similarly, a 2018 study published in JAMA Open Network found that FDA between 2007 and 2016 had flagged 746 dietary supplements as having unapproved or recalled pharmaceuticals, including steroids and erectile dysfunction drugs. However, according to Aschwanden, only 48% of the flagged pharmaceuticals were voluntarily recalled by manufacturers; most of the supplements continued to be sold.

In addition, Cohen said many supplements suffer from another issue, called "economic adulteration," in which manufacturers use less expensive, impure ingredients instead of more expensive, pure ones. For instance, the manufacturer of might use the "scraps" of a garlic plant rather than the bulb. According to Cohen, the substitution may take place when raw ingredients are being manufactured, so a company purchasing the raw ingredients to make supplements may be unaware of any problems.

Loren Israelsen, president of the United Natural Products Alliance, said while economic adulteration is "a violation of federal law under the Food, Drug, and Cosmetic Act," it nonetheless remains "a persistent problem for all industries that sell higher value commodities."

Limited oversight and rapid growth

According to Cohen, contaminated supplements continue to proliferate in part because of the Dietary Supplement Health and Education Act of 1994 (DSHEA), which he said leans more toward providing access to supplements rather than ensuring their safety.

Under DSHEA, FDA's ability to provide oversight for supplements is limited, Aschwanden writes, and many new dietary supplements enter the market without first being evaluated. Courtney Rhodes, a spokesperson for the FDA, told the Post that the agency "currently has no systematic way of knowing what dietary supplements are on the market, when new products are introduced, or what they contain."

Separately, Peter Lurie, a former FDA official and current executive director of the Center for Science in the Public Interest, said that "there is no systematic monitoring of safety and effectiveness" for supplements at FDA.

Despite these limits, the agency does intervene when it can, Aschwanden writes. For instance, according to Rhodes, FDA over the past year has acted against "products whose labeling claimed the products would treat or prevent hangovers, depression, and other mental health disorders." These products were labeled as dietary supplements but were "unapproved new drugs and/or misbranded drugs," she said.

And FDA is working to expand its authority. The agency's 2020 and 2021 budget requests included a legislative proposal that would "require all products marketed as 'dietary supplements' to be listed with the FDA and give the agency authority to act against noncompliant products and the manufacturers and/or distributors of such products," Rhodes said.

However, in addition to a current lack of authority on the issue, FDA also does not currently have the funding needed to provide oversight to the massive supplement industry, Aschwanden writes.

Israelsen said the supplement industry grew from being worth $5 billion in 1994 to around $50 billion today. "You have 10 times growth over 20 years—that's remarkable, but I can assure you the FDA budget did not increase by 10 times," he said.

5 ways to choose safe, reliable supplements

To help consumers wade through the proliferation of supplements and choose ones that are safe and reliable, experts have offered a few tips, Aschwanden reports.

1. Look for simple ingredients. Cohen recommends that consumers choose supplements with simple ingredients that do not make over-the-top claims, like suggesting that they can treat or prevent an illness.
2. Purchase supplements from reputable stores. Israelsen said supplements sold cheaply online may have hidden ingredients or impurities. Other supplements in major retail chains tend to have to go through a vetting process.
3. Avoid products on FDA's Dietary Ingredient Advisory List. The list covers products containing ingredients that may not comply with FDA rules. The ingredients on the list have not necessarily been labeled as unsafe, but FDA is looking into them, Aschwanden writes.
4. Find supplements that have been certified by outside parties. Cohen recommends products that have been certified by U.S. Pharmacopeia, calling it "the gold standard."
5. Avoid certain types of supplements. There are several types of supplements that consumers may want to avoid, Aschwanden writes. A 2018 study found that supplements promoting sexual enhancement, weight loss, or muscle building were the ones most likely to be contaminated. (Aschwanden, Washington Post, 6/30)