The Chinese herbal aristolochic acid, banned in several countries for causing kidney failure and cancer, is readily available from websites, according to a US researcher, warning of the need for better regulation of the Internet.
Herbal products containing Aristolochia species were banned in Germany 20 years ago, and they are also banned in Japan, Malaysia, New Zealand and the UK. Two years ago the US Food & Drug Administration (FDA) also banned the import of such products.
But in a letter in the current issue of The New England Journal of Medicine, Lois Swirsky Gold, a University of California, Berkeley researcher, reports finding 19 products on the web known to contain aristolochic acid and 95 products suspected to contain the chemical.
The chemical has been associated with more than 100 cases of rapid kidney failure, due to the use of a dietary supplement in which the dangerous chemical had been substituted for another herbal extract used in a Belgian clinic in 1993. Half of the 39 women who had their kidneys removed after taking the supplement were found to have cancer of the urinary tract, the letter notes. Kidney failure associated with aristolochic acid has been seen in eight other countries and urothelial cancer in two other countries, Gold said.
"Aristolochia and aristolochic acid are known human and rat carcinogens," Gold said in an interview. "What is also disturbing is that the recommended dose for at least one product on the Internet is the same as the dose that gave cancer to rats. These products should not be available."
The sale of such supplements through the Internet poses a considerable threat to the dietary supplements industry, damaging its reputation among legislators and consumers.
"The failure to protect the public from the imminent hazard of aristolochic acid indicates that there is an urgent need to remove these products from the web and to develop a policy that addresses web sales of hazardous herbal products," urged the letter.
Products containing aristolochic acid are called a variety of names including fang ji (Aristolochia fangchi) and wild ginger (Asarum canadense). Herbal products marketed as "Cramp Relief', 'Cold Away,' 'Mother Earth's Cough Syrup', 'Old Indian Herbal Syrup' and 'PMS-Ease', are recommended for gastrointestinal symptoms, weight loss, cough, immune stimulation and menstrual cramps, among others.
But the letter also warns that "... aristolochic acid is among the most potent 2 per cent of the carcinogens in our Carcinogenic Potency Database."
The database analyzes long-term cancer studies performed in animals. Gold claims that natural chemicals are just as likely to cause cancer as man-made chemicals.
"The fact is, in our database, half the naturally occurring chemicals turn out to be carcinogens just the way half the synthetic chemicals do when they are tested," she said. "Also, many natural agents that have been present throughout vertebrate evolutionary history, such as aflatoxin or the common elements beryllium and arsenic, cause cancer in people."