WEDNESDAY, Oct. 15, 2003 (HealthDayNews) -- Despite a 2001 government import ban, U.S. consumers still have ready access to diet aids that contain a plant extract linked to kidney failure and urinary tract cancers.
California scientists say they've identified 19 products containing the substance, aristolochic acid, for sale on the Internet from sites based in the United States. They also found 95 other products that may be adulterated with the toxin, which has been used in traditional Chinese medicine for millennia. The products range from weight-loss aids and cough suppressants to stomach soothers and purported immunity boosters.
The researchers say the failure of the U.S. Food and Drug Administration (FDA) import freeze to protect consumers underscores the agency's general weakness in regulating diet supplements. Congress has exempted herbal product makers from having to prove the safety and effectiveness of their products before obtaining FDA approval to sell them.
Aristolochic acid "shouldn't be there, but it is," says Lois Swirsky Gold, director of the Carcinogenic Potency Project at the University of California, Berkeley, who conducted the investigation with a colleague, Thomas Slone.
A letter on the study appears in the Oct. 16 issue of the The New England Journal of Medicine.
Gold says she doesn't know whether the products entered the country in violation of the FDA embargo or if they are simply backlogged items still for sale.
Whatever the case, consumers should avoid them, she adds. "They don't want to buy products that contain aristolochic acid," she stresses.
Michael McGuffin, president of the American Herbal Products Association in Silver Spring, Md., says in a statement that the Dietary Supplement and Health Education Act (DSHEA) gives the FDA the authority to require that such products are safe for their intended use.
"FDA has stated that it will not tolerate the presence of herbs containing [aristolochic] acid in dietary supplements. The American Herbal Products Association has clearly communicated that message to its members," McGuffin states. "FDA has the legal authority under DSHEA to take action against companies that do not comply with the law, and the American Herbal Products Association fully supports FDA in doing so."
The FDA did not respond to requests for comment.
The agency moved to ban imports in 2001 after it had cautioned health-care professionals on two instances in the United Kingdom in which people developed kidney failure after taking products containing aristolochic acid. In the early 1990s in Belgium, the agency also said at the time, more than 100 cases of kidney damage were traced to a dietary supplement containing the substance; at least 70 of those patients needed kidney transplants or dialysis. And a study published in 2000 in the New England Journal of Medicine showed a high rate of urothelial carcinoma, a form of urinary tract cancer, in people who used Chinese remedies with the substance.
The FDA has acknowledged that consumers might have a hard time recognizing aristolochic acid when they see it. The toxin has more than a dozen forms, and its plant family has roughly 600 members.
Three main ingredients, "Aristolochia," "Bragantia" and "Asarum" may be contaminated with aristolochic acid, according to the agency. Other ingredients that may contain the substances include: Aristolochia spp., Asarum spp., Bragantia spp., Stephania spp., Clematis spp., Akebia spp., Cocculus spp., Diploclisia spp., Menispernum spp., Sinomenium spp., Mu tong, Fang ji, Guang fang ji, Fang chi, Kan-Mokutsu and Mokutsu. Aristolochic acid might also appear in Dutchman's pipe, birthwort and wild ginger.
More information
For the list of products known or suspected to contain aristolochic acid, try the Carcinogenic Potency Project. For more on aristolochic acid, visit the U.S. Food and Drug Administration.
