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Certain Chinese herbal medicines linked to types of cancer: study

2012/04/10 19:52:24

Taipei, April 10 (CNA) Chinese herbal medicine containing extracts of aristolochia acid (AA) increases people's chances of getting kidney and a type of bladder cancer, according to a Taiwanese study published in an international scientific journal Monday.

AA extracts are commonly found in plants in the aristolochia family, such as aristolochia debilis (Dutchman's pipe) -- common in Chinese herbal medicine, and other plants in the bragantia or asarum family that are consumed around the world.

The number of Taiwanese diagnosed with kidney or urothelial cancer is significantly higher than the number of people diagnosed with the diseases in most Western countries, where Dutchman's pipe is not traditionally consumed, the study by National Taiwan University Hospital's (NTUH's) Department of Urology noted.

Of the 151 kidney and urothelial cancer cases studied, metabolites from AA -- previously shown to be carcinogenic in animals tests -- were found in 97 cases, according to Chen Chung-hsin, a doctor with the urology department, Tuesday.

Moreover, further studies showed that in 83 percent of the detected cancer cases, AA caused specific mutations in a gene that suppresses tumor growth, explained Chen, who added he was uncertain how much AA would have to be consumed to cause cancer.

Some experts have claimed that consuming over 60 milligrams of AA extracts from caulis aristolochiae manshuriensis increases the risk of getting cancer.

While Taiwan's Department of Health banned the use of AA in Chinese medicines, as well as all imports and exports of the substance, in 2003, AA can effect the human body for decades, according to a January NTUH press release.

Every year 3,000 patients in Taiwan are diagnosed with kidney and urothelial cancer, and up to 1,000 patients die annually from the disease, the press release noted.

Moreover, the press release pointed out that Taiwan and the Balkan countries, where aristolochia plants are consumed, have the highest rates of kidney and urothelial cancer, but compared with Western countries where the diseases are mostly caused by smoking, only four percent of Taiwanese patients smoked.

According to the results of an earlier study in Belgium, high rates of kidney and urothelial cancer in Balkan countries were linked to the mixing of aristocholia plants with wheat.

(By Chen Ching-fang and C.J. Lin)