Science-- there's something for everyone

Monday, May 7, 2012

Herbal remedies can kill

If you need a reason to be wary of herbal remedies, take a lesson from the Taiwanese. They’re suffering from the highest rate of upper urinary tract cancer in the world, thanks to Chinese herbal remedies made from the Aristolochia plant (left). Many species of this plant produce aristolochic acid (AA), a nasty substance that’s a powerful nephrotoxin, meaning it will destroy your kidneys. Now it turns out that AA is a carcinogen as well. Nonetheless, it’s been a component of traditional medicines for centuries.

The connection between AA and kidney failure has been known for decades, but the relationship with certain types of cancer was uncovered by Chung-Hsin Chen of National Taiwan University Hospital and Taoyuan General Hospital and his Taiwanese and American colleagues. They took DNA samples from patients suffering from urinary tract cancer to find that correlation.

The researchers relied on the fact that AA forms long-lasting chemical bonds with DNA. Because of that, specific mutations can be linked to AA exposure. Those same mutations were found in a large majority of the cancer patients, strongly suggesting that the cancers were caused by the ingestion of AA. The fact that one third of all Taiwanese people are known to use remedies containing AA (as estimated from examining the prescription records of 200,000 people) makes it even more likely that the unfortunate study subjects had taken AA. I can only hope that word will get out and people will stop taking these dangerous concoctions.

By the way, think your preferred herbal remedies are safe? Keep in mind that the Food and Drug Administration (FDA) has minimal oversight over herbal remedies. In the case of AA, the best they can do is to ban its import, they have no authority to make sure that remedies don’t contain it. Besides, many herbal products interfere with conventional treatments as Catherine Ulbricht, Senior Attending Pharmacist at Massachusetts General Hospital, describes here.

Hat tip: Skeptics’ Guide to the Universe.