More than 23,000 Americans are treated in hospital emergency rooms each year for heart problems, allergic reactions, overdoses and other complications related to taking dietary supplements, according to a new study published Wednesday in the New England Journal of Medicine (NEJM).

Approximately 10 percent of those ER visits — or about 2,150 cases  — are serious enough to require hospitalization, the study also found.

Although these numbers represent less than 5 percent of the ones previously reported for prescription drugs, they are still very concerning because dietary supplements “are regulated and marketed under the presumption of safety,” write the study’s authors.

As I’ve noted here many times before, Congress has limited the ability of the U.S. Food and Drug Administration (FDA) to regulate dietary supplements. The manufacturers of supplements do not need FDA approval before they start selling a product, and the agency can only act to restrict a dietary supplement after it has been on the market and demonstrated to be unsafe — in other words, after it starts causing harm to people.

Most Americans are unaware that the safety of dietary supplements — which include vitamins and minerals as well as herbal, homeopathic and other “complementary nutritional” products  — is initially determined by the corporation selling them rather than by health regulators. Yet almost half of all adults in the United States take at least one supplement within any given month, according to surveys.

In 2007, Americans spent $14.8 billion of their own money on dietary supplements — about one-third of the out-of-pocket money they spent that year on prescription drugs.

Study details

The current study was conducted by a team of researchers from the FDA and the Centers for Disease Control and Prevention (CDC). They are careful to point out, however, that this is not an official government study, and its findings “do not necessarily represent the official position” of those two agencies.

For the study, the researchers analyzed data collected from 2004 to 2013 from a representative sampling of 63 hospitals across the country. They identified about 3,700 supplement-related ER visits to those hospitals during that 10-year period, including 400 cases in which the person was admitted to the hospital. 

From these numbers, the researchers estimated that 23,005 Americans are treated in hospital emergency rooms and 2,154 are hospitalized for supplement-related complications each year.

But those numbers are likely to be underestimates, say the researchers, for many people probably seek care from their personal doctor for an adverse reaction to a supplement, or they may simply treat the problem themselves at home. In addition, this study did not include ER visits related to energy drinks, herbal teas or other products that are marketed as dietary supplements but considered “food.”

Here are some of the other key findings from the study:

• More than one-quarter (28 percent) of the ER visits occurred among young adults aged 20 to 34 years. Most of these complaints were cardiovascular problems — chest pain, heart palpitations and irregular heart rhythms — and were associated with products marketed for weight loss or energy enhancement. In fact, heart problems related to supplements were found to be a more common diagnosis in hospital emergency rooms than those associated with prescription stimulants.
• Slightly more than one fifth (21 percent) of the supplement-related ER visits involved unsupervised children who had found a container of vitamins and minerals and swallowed them. “Child-resistant packaging is not required for dietary supplements other than those containing iron,” write the study’s authors, “and despite such packaging, iron supplements were the second most commonly implicated type of supplement in unsupervised ingestion by children.”
• About one-third (29.9 percent) of the supplement-related ER visits by adults aged 65 and older were related to just three particular micronutrient supplements: calcium, iron and potassium. Choking problems were the most common reasons for ER visits involving calcium products, while abdominal symptoms (nausea, vomiting and abdominal pain) were the reasons most frequently linked to iron and potassium supplements.
• Adults aged 65 and older were twice as likely to be hospitalized for supplement-related adverse events than those aged 20 to 34.

You’ll find an abstract of the study on the NEJM website, but the full study — despite being funded in part by public monies (the Department of Health and Human Services) — is behind a paywall.