Some herbs that are used in traditional Chinese medicine (TCM) have been linked to liver cancer across Asia.
A recent study conducted by a team of scientists which included experts from the National Cancer Centre Singapore, Duke-NUS Graduate Medical School Singapore and Taiwan’s Chang Gung Memorial Hospital suggests that “stronger measures are needed to prevent people from consuming chemicals called aristolochic acids (AA), which are derived from the woody vines of the Aristolochia plant family,” according to The Straits Times.
Also known as birthwort, Aristolochia has been used for parasite prevention during childbirth since the days of Ancient Greece. Asian practitioners sometimes give it to women during childbirth to expedite healing. In recent years, it has also been used as an herbal remedy for weight loss around the world. In Vietnam, AA can be found in some herbal remedies that feature parts of plants from the Aristolochia genus (mộc hương) and Asarum genus (tế tân).
An examination of 98 liver tumors tested in Taiwan showed that 78% contained mutation patterns indicating that the cancer was likely caused by contact with AA chemicals. In China, 47% of the 89 samples taken for the study showed the “well-defined mutation signature,” and in Vietnam, five of the 26 tumors were a match.
"Although we knew that there was exposure to AA in Taiwan, we were very surprised to find [that] such a high proportion of liver cancer sufferers had exposure to AA," said Professor Hsieh of Taiwan’s Chang Gung Memorial Hospital.
In 2003, Taiwan banned certain products containing AA; however, neither Taiwan or China have implemented any ban relating to the plant in its entirety. The research also showed no drop in AA-associated liver cell mutations after Taiwan's above-mentioned ban. This could be because it takes time for a drop in cancer rates to show up in the data, or it could be because people are still exposed to AA in other products.
As AA has been banned in the United States and United Kingdom for over a decade, it is unsurprising that the research showed almost no link in North American (5%) and European (1.7%) samples.
AA has also been linked to renal failure in Asia and a kidney disease known as Balkan nephropathy, as the condition is prevalent in that region of Europe.
Before you fire your TCM practitioner, keep in mind that many other traditional treatments and herbs have been proven safe and effective as complementary preventative measures for cancer and other ailments. For example, the barberry tree, or hoàng liên gai, contains berbamine, which is widely considered a novel way to treat liver cancer.
[Top photo: an assortment of generic ingredients used in traditional Chinese medicine. Photo via The Straits Times]
