In an example of the dangers of untested and unregulated herbal products, doctors are reporting that a Chinese herb, already linked to kidney failure, may cause cancer as well.
The herb, Aristolochia fangchi, was given to patients at a weight-loss clinic in Belgium from 1990 to 1992, according to a report being published today in The New England Journal of Medicine. By 1993 more than 100 of the patients had kidney damage, and so far more than 70 of them have suffered kidney failure, requiring transplants or dialysis. Now, some of these patients are also developing cancers of the urinary tract. The report gave no indication how many patients might have taken the herb at the clinic.
Cases of kidney failure from the herb have also been reported in France, Britain, Spain, Japan and Taiwan. Dr. Christine Lewis, director of the office of nutritional products, labeling and dietary supplements at the Food and Drug Administration, said there had been no reports of Americans being harmed by Aristolochia. Dr. Lewis also said the drug agency did not know how much of the herb might be on the market in this country.
In a check of 14 stores in New York City yesterday, Aristolochia fangchi was available at 2 stores. At one, it was being sold under the name of Aristolochia sertentaria for $13.95 an once. The other store said that it had Aristolochia fangchi available under the name Senega snake root and that it was used to heal snake bites.
Last month, the F.D.A. sent letters to doctors and to the supplement industry, with a six-page list of herbal remedies known or suspected of containing Aristolochia. The agency urged manufacturers to test their products for the presence of the herb.
The F.D.A. is also preparing to issue an ''import alert'' within a few weeks that will, in effect, ban importation of the herb, including every item on the six-page list, Dr. Lewis said.
Dr. John Cardellina, vice president for botanicals at the Council for Responsible Nutrition, a trade group for the supplement industry, said Aristolochia had been found in some Chinese medicinal mixtures, but in few other products. Nonetheless, Dr. Cardellina said, because Aristolochia is so dangerous, the supplement industry supports the drug agency's decision to list every item that might possibly contain the herb.
Herbs, amino acids, vitamins and other so-called dietary supplements are now a $15 billion industry, which is largely unregulated. Unlike drugs, supplements do not have to be proved safe and effective before they are marketed, and no outside agency even checks to make sure that the products actually contain the ingredients on the label. Regulation is lacking because in 1994, Congress passed the 1994 Dietary Supplement Health and Education Act, which cut back the authority of the the Food and Drug Administration.
The report published today in The New England Journal of Medicine tells of 39 patients who took the herb and had kidney transplants or dialysis at Erasme Hospital in Brussels, by a team led by Dr. Joelle L. Nortier. Eighteen of the 39 have also developed cancers of the urinary system. Nineteen others have abnormal cells in the urinary tract, possibly precancers.
In an editorial accompanying the article, Dr. David Kessler, former head of the Food and Drug Administration and now dean of the Yale School of Medicine, urged Congress to change the law to give the F.D.A. more power over supplements.
Dr. Kessler said he had bought a bottle of Aristolochia capsules, sold as ''Virginia Snakeroot,'' from an American supplier via the Internet.
At the Belgian weight-loss clinic, Aristolochia was given to patients by mistake; doctors had prescribed another herb, but the product that the patients were given was later found to contain Aristolochia, possibly because of a manufacturing error. On average, the patients took it for about a year.
Aristolochia contains compounds called aristolochic acids, which are known to damage the kidneys and to cause cancer in rats in the laboratory.