Which Work? Who’s Minding the Store?

Dec. 28, 2023 – The market for dietary supplements – vitamins, minerals, botanicals, herbs, and other products promoted as ways to help you feel better, look better, perform better, sleep better, and stay healthy – is booming, and that boom isn’t done. In 2021, U.S. consumers spent more than $48 billion on supplements; that number is projected to grow more than 5% annually over the next 5 years. 

The industry grew from about 4,000 products in 1994 to 80,000 in 2016. At least half of U.S. adults take dietary supplements, according to 2021 federal statistics. Three-quarters of the people who took a 2023 consumer survey done by the Council for Responsible Nutrition, the trade association representing supplement makers and ingredient suppliers, said they take supplements.

Despite this enthusiasm, experts worry about adverse effects from mega doses and point out the lack of evidence of benefit for many supplements. More government oversight is sorely needed, others say. Currently, the FDA’s role in regulating supplements usually begins only after the product is on the market.

Profile of a Supplement User

While some consumers are seasonal or occasional users, others are passionate supplement takers like Suzanne Bank, an interior designer in Studio City, CA. Among her regular supplements are vitamin C, apple cigar vinegar for digestion, tri-magnesium for healthy muscle function, and cat’s claw, promoted for brain health. 

“They have kept me going, kept me leading an active life,” said Bank, who said she is past “typical” retirement age but still operates her own business. “I’m healthy, I don’t get sick, and I look far, far younger than my age.”

Bank said she hasn’t had any adverse effects, even after more than 40 years of regular supplement use.

So, Which Supplements Work?

According to the FDA, dietary supplements can help improve or maintain overall health, as well as help people meet the daily requirements of essential nutrients. It also says: “While the benefits of some supplements are well established, other supplements need more study.” It cautions that supplements should not take the place of a variety of foods crucial for a healthy diet.

Most people view supplements, at worst, as benign preventive products, said Jeffrey A. Linder, MD, MPH, chief of general internal medicine at Northwestern University’s Feinberg School of Medicine in Chicago. But they aren’t always harmless. With too much emphasis and reliance on supplements, Linder said, “I’m more worried that people are getting distracted from things that will actually help them be healthy, like exercise, eating a healthy diet, and maintaining a healthy weight.” 

While there’s no one-stop reference on which supplements are worth taking, various organizations as well as researchers attempt to summarize the evidence and issue conclusions. Recently, the U.S. Preventive Services Task Force issued recommendations on the evidence for supplements in preventing cardiovascular disease (diseases of the heart and blood vessels) and cancer. 

Linder co-wrote an editorial to go with those recommendations. In summary, he said, the task force concluded that “there is insufficient evidence about pretty much all supplements” for preventing cardiovascular disease and cancer, and specifically recommended against vitamin E and beta carotene for preventing those diseases.

Overall, some of the strongest evidence, Linder said, is for prenatal folic acid supplements to prevent birth defects, citing a previous recommendation by the task force. 

While the task force rating of “I” for insufficient evidence given to most supplements isn’t a vote for or against use, Linder said, current evidence shows that any benefit of a multivitamin in reducing the risk of death from heart disease is likely to be a small one.

Vitamin D supplements are popular for those hoping to boost bone health, reduce cancer risk, and ease inflammation. But proving vitamin D supplements help those who are not naturally deficient in vitamin D is difficult, Linder said, noting that the task force didn’t find evidence that vitamin D reduced cancer or cardiovascular disease risk.

“I think there are many more people taking vitamin D [supplements] unnecessarily than there are people benefitting from a vitamin D supplement,” he said. Likewise, the task force didn’t find evidence that vitamin C reduced cancer risk or cancer death risk.

What Works? Research on Supplements for Musculoskeletal Health

In a special issue of the journal Nutrients, researchers submitted 13 studies and four reviews of studies, concluding that a wide variety of supplements can help improve the health of bones and muscles in people with and without certain diseases.

A sampling of their findings:

  • Vitamin D can reduce pain in those with fibromyalgia and other painful conditions.
  • Creatine can give athletes an edge in sprinting.
  • Polyphenols may improve sports and exercise performance and speed recovery after workouts.
  • Collagen can improve joint health.

Supplements du Jour

In recent years, “beauty” supplements that promise to improve skin, hair, and nails have gotten more popular, with their use doubling from 2012 to 2020, according to a national health survey of nearly 41,000 people. 

Consumers should be cautious taking these, said Rajani Katta, MD, a Houston dermatologist who is on the volunteer faculty of McGovern Medical School at the University of Texas and Baylor College of Medicine in Houston. Katta has published information on these types of supplements. Biotin, which supplement makers claim can help with hair and skin health, for instance, can interfere with thyroid and cardiac function testing, she said. Heavy metals have been found in collagen supplements.

“If you are on a supplement with high levels of biotin, you need to tell your doctor,” Katta said. “It could interfere with testing.” Avoid supplements that list “proprietary blends” as an ingredient, she said, as that does not tell you which ingredients are in it.

Solution: More Oversight?

The 1994 Dietary Supplement Health and Education ACT, or DSHEA, established regulations for dietary supplements. Under it, the FDA typically does not review dietary supplements before they go to market, and supplement makers don’t have to give the FDA basic product information, such as names or ingredients, before putting them up for sale.

As a result, the FDA mainly relies on post-market surveillance to monitor product safety, restricting use or ordering a recall only if there’s proof that a product or ingredient is not safe.

The growing market for supplements means growing risk, according to experts pushing for more oversight. In spelling out the need, researchers writing in the AMA Journal of Ethics cited a study finding that the FDA’s central reporting system (CFSAN Adverse Event Reporting System, or CAERS) received more than 15,000 health problem reports linked to supplements, including 339 deaths and nearly 4,000 hospitalizations. 

Bipartisan legislation to beef up the oversight of the supplement industry was introduced in the Senate in 2022. The bill, by Senate Majority Whip Dick Durbin (D-IL) and Sen. Mike Braun (R-IN), would require dietary supplement makers to list their products with the FDA. Introduced in April, 2022, it was referred to the Committee on Health, Education, Labor and Pensions. 

Industry Views

The Council for Responsible Nutrition counters that solid evidence backs the use of many supplements. In 2022, it issued a report, Supplements to Savings, about the health care cost savings with the use of targeted supplements for specific conditions. They found benefit for, among other supplements, omega-3 fatty acids for cardiovascular disease, vitamin D for osteoporosis-related fractures, and magnesium for cardiovascular-related disease events. Vitamin D with calcium, for instance, reduced the risk of a fracture by 14%. 

The industry supports the idea of more oversight, said Steve Mister, CEO and president of the Council for Responsible Nutrition. For instance, he said, his organization strongly supports the Durbin bill, which wants supplement makers to list their products with the FDA. “The basic idea of the bill is something that CRN is strongly supportive of.”

It’s a problem, he said, that the FDA has no way of knowing how many supplement products are on the market. The Durbin bill would have set up a registry of sorts, not premarket approval but access to information about products, which Mister sees as something the FDA needs.

The existing law will be 30 years old in 2024, Mister pointed out, and it’s past due for an overhaul to achieve reform and maintain safety. 

Consumer Actions

You can do much on your own to ensure the safety of the supplements you take. Tell your doctor about any supplement you are taking or planning to take, and expect your doctor to bring up the topic during visits.

When shopping, look for a label that says the supplement has been inspected by an outside lab, such as NSF or Consumer Lab.

Consult interaction checkers to be aware of which supplements don’t mix well with which medicines. You can report any problems with supplements to the FDA’s Safety Reporting Portal online.

Bank, the interior designer who’s passionate about her supplements, is smart about working with her doctor. “I’ve run all these by my doctor,” she said.

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