Weight-loss and energy supplements sold in the United States may contain potentially harmful and inaccurately labeled levels of the banned stimulant higenamine, a new study finds. The study was published in the journal Clinical Toxicology.
Higenamine is on the World Anti-Doping Agency's list of substances prohibited in sports, though it is legal for use in supplements in the United States, Canada and Europe.
"We're urging competitive and amateur athletes, as well as general consumers, to think twice before consuming a product that contains higenamine," said study co-author John Travis.
Doping Risk for Athletes
"Beyond the doping risk for athletes, some of these products contain extremely high doses of a stimulant with unknown safety and potential cardiovascular risks when consumed," said Travis, senior research scientist at the public health organization NSF International in Ann Arbor, Mich.
"What we've learned from the study is that there is often no way for a consumer to know how much higenamine is actually in the product they are taking," Travis said in an NSF news release.
Duffy MacKay is senior vice president of science and regulatory affairs at the Council for Responsible Nutrition, which represents the supplements industry. He said CRN isn't familiar with higenamine or companies that sell it, and ultimately it's up to the U.S. Food and Drug Administration to curb the sale of banned substances.
In the meantime, "CRN recommends that consumers always first consult with their doctor or health care practitioner to help determine which dietary supplements are right for them," MacKay said.
"Consumers also need to be savvy shoppers—choosing brands they trust and purchasing from reputable retailers, distributors or websites. It is also important to avoid products whose claims sound too good to be true," he said.
Products containing higenamine
In the new study, Travis and researchers analyzed 24 products labeled as containing higenamine or the synonyms "norcoclaurine" or "demethylcoclaurine." They found unpredictable and potentially harmful amounts of the stimulant that varied from trace levels to 62 milligrams a serving. Of the 24 products, only five listed a specific quantity of higenamine on the label, and none of those was accurate.
Study co-author Dr. Pieter Cohen is an associate professor of medicine at Harvard Medical School. "Some plants, such as ephedra, contain stimulants. If you take too much of the stimulants found in ephedra, it can have life-threatening consequences. Similarly, higenamine is a stimulant found in plants," he said.
"When it comes to higenamine, we don't yet know for certain what effect high dosages will have in the human body, but a series of preliminary studies suggest that it might have profound effects on the heart and other organs," Cohen said.
Dietary supplements are linked with 23,000 visits to U.S. emergency departments each year. Weight-loss and sports supplements account for a large portion of such visits, the researchers noted.