Tens of thousands of Americans are treated in hospital emergency rooms each year for problems caused by dietary supplements, federal health officials are reporting.
The complications include heart problems such as irregular or rapid heartbeat or chest pain, says Dr. Andrew Geller of the federal Centers for Disease Control and Prevention, who led the study published Wednesday in the New England Journal of Medicine.
Two other big problems are children ingesting supplements purchased by an adult, or older people choking on pills, he says. Nearly three-fourths (71.8 percent) of the ER visits were related to the use of weight-loss or energy-boosting supplements.
The analysis, based on data collected between 2004 and 2013, is the first national estimate of complications that result from using dietary supplements, Geller says.
Using data from 63 emergency rooms, he and his colleagues calculated that 23,005 emergency room visits occur each year because of dietary supplements. Among those cases, 2,154 patients are hospitalized to receive further treatment.
The analysis did not include anyone who might have died on the way to the hospital or in the ER because those deaths are not recorded in the database used for the study.
Geller says it's hard to know which products can cause problems or why. Unlike standard over-the-counter medications or prescription drugs, the companies that make dietary supplements are not required to prove to the Food and Drug Administration that their products are safe and effective before selling them.
"We don't have information about what's contained in these products," Geller says. "And often times multiple active ingredients are combined into a single product." In addition, similarly named products can have very different active ingredients, he says.
"For all those reasons it can be hard for consumers, clinicians and public health agencies to determine which, if any, of the specific active ingredients caused the observed effects," Geller says.
In recent years, some dietary supplements have been recalled when they are found to contain unapproved ingredients or contaminants. But Geller says "there's very little national data about how products that are not included in such recalls cause health problems."
Dietary supplements have become increasingly popular in the United States. Americans spend nearly $14 billion a year on vitamins, minerals, herbal remedies to treat a wide range of conditions, including colds, arthritis and immune system problems, and to promote weight loss.
Critics of the dietary supplement industry are welcoming the new research.
"This is the most important study that been published on supplements in the last 20 years," says Dr. Pieter Cohen, who studies supplements at Harvard Medical School.
"What this study does is find entirely flawed the underlying premise that supplements are safe," Cohen says. "In fact, supplements are now shown by this elegant CDC study to send tens of thousands of people to emergency rooms every year."
The findings, he says, show there's a need to better track problems caused by supplements so the FDA can identify and remove dangerous supplements from the market sooner.
Dietary supplement companies, however, see the study as demonstrating the relative safety of supplements.
"If you put it in context that over 150 million Americans take dietary supplements each year, we have, 'Far less than one-tenth of 1 percent of supplement users will visit the ER,' " says Duffy MacKay, a naturopathic doctor and the senior vice president for scientific and regulatory affairs at the Council for Responsible Nutrition, a trade group.
MacKay argues that the study overestimates the dangers by including problems caused by products that aren't supplements — such as homeopathic remedies.
He also says any problems caused by supplements could be minimized by keeping the products away from children, developing pills that won't choke older people, and educating young people about how to use the products more carefully.