Introduction
There is a widespread misconception that anything found in nature (and is thus “natural”) and commercially available must be safe. In fact, this is not true. Many plants and animals form compounds that can be extremely hazardous to humans. For example, aristolochic acid, a component of certain Chinese herbal medicines, is well known to cause severe kidney failure and cancer of the urinary tract system. To date, a significant number of Chinese herbal medicines have been identified containing aristolochic acid, including those products with the words "Aristolochia," "Bragantia" or "Asarum”. Despite import bans for this dangerous compound by various governments, herbal medicines containing it are still available through the internet or from unethical manufacturers or dealers.
Kidney Failure
Kidney disease associated with aristolochic acid (called Chinese Herbal Nephropathy) can lead to end-stage kidney failure relatively quickly. Chinese Herb nephropathy was first identified in Belgium in the 1990’s. About 100 patients with kidney failure were found to have taken a “slimming regimen” that was later identified as aristolochic acid. The kidney biopsies among these patients were very similar showing extensive and severe scarring of the kidneys. At least 70 of those patients went on to require dialysis or kidney transplantation. Additional cases of Chinese Herbal nephropathy were later identified in France, United Kingdom and the United States. As a result, in 2001, the U.S. FDA issued a severe warning and import ban for dietary supplements containing this compound.
Urinary Tract Cancer
Kidney failure is not the only toxicity of Chinese herbal medicines containing aristolochic acid . In 2000, an article in the New England Journal of Medicine reported the pathological findings of 39 patients with Chinese-herb nephropathy who were evaluated for urinary tract cancers. It was found that almost 50% of the people with Chinese Herb nephropathy had evidence of cancers involving the ureter, bladder and renal pelvis. Most of the remaining patients (who did not have cancer obvious cancer) had evidence of lesions that are precursors for cancer.
Recognizing the Danger
The key to protecting yourself is recognizing the danger. It is important to realize that herbs and other “natural” products have the potential for serious side effects, just like traditional medicines. However, unlike traditional medicines, herbal medicines are not subject to vigorous regulation. Even when there is a government ban on a particularly dangerous herbal component, you still may be at risk. For example, the Lancet recently reported a case of man in the United Kingdom getting kidney failure and multiple urinary tract cancers from a Chinese herbal medicine containing aristolochia. He was able to get it for five years despite a ban on aristolochia in the UK. This case highlights how dangerous herbal remedies can still be bought on the internet or from unethical manufacturers or dealers. The old adage “let the buyer beware” is particularly important for herbal medicines as well as traditional medicines.
Sources
- Chinese Herbal Medicine Linked to Bladder Cancer, Nephropathy. Reuters Health Information. July 20, 2006. Accessed July 21, 2006.
- Robert Sanders. Dangerous herbal readily available through Web despite FDA import ban”. U.C. Berkeley News. October 16, 2003. Accessed July 21, 2006.
- U.S. FDA Consumer Advisory. April 11, 2001. Accessed July 21, 2006.
- U.S. FDA Dietary Supplement Warning. Accessed July 21, 2006.
- William Shiel, MD. Herb Danger - Aristolochic Acid Warning. MedicineNet.com. Accessed July 21, 2006.
- Nortoer et al. Urothelial Carcinoma Associated with the Use of a Chinese Herb (Aristolochia fangchi). NEJM 342 (2000): 1686-1692
- Chang et al. Rapidly Progressive Interstitial Renal Fibrosis Associated with Chinese Herbal Medications. American Journal of Nephrology 21 (2001):441-448