There are polarising views on the subject of complementary and alternative medicines (CAM). This website has recently published numerous article about the efficacy and regulation of CAM, the placebo effect and whether universities should train practitioners.
We don’t intend to cover this well-trodden ground. Rather, we’re sharing the results of research into the legality, safety and honesty in the labels of some traditional Chinese medicines (TCM).
When you buy a food product at the supermarket, you expect the manufacturing standards to be high; the product to be safe; and the ingredient list to accurately depict what’s in the product – regardless of whether it is locally grown or imported.
Surely the same or an even greater level of honesty is expected of medicines. Few would argue that consumers shouldn’t be provided with accurate information about medicinal products before deciding to ingest them.
This is especially important for CAM because the majority of herbal medicines are self-prescribed and administered. And because traditional Chinese and other herbal medicines are commonly processed into powders, pills or teas it’s difficult to reliably identify all their ingredients.
We set out to investigate the biological origins of traditional Chinese medicines by examining the DNA signatures of animals and plants contained within 15 medicines. The aim of our research, published today in the journal PLoS Genetics, was to see if new DNA sequencing technologies were effective in providing detailed audits of the plant and animal ingredients within selected products.
The results of the genetic audit don’t make pretty reading: we found this collection of traditional Chinese medicines routinely contain undeclared plants and animals, some of which are illegal.
What’s in a horn?
One product labelled 100% “Saiga Antelope Horn Powder” contained DNA of Saiga antelope (an endangered species protected by the Convention on International Trade in Endangered Species of Wild Fauna and Flora (CITES)) – so this ingredient was accurately declared.
But DNA from sheep and goat were not mentioned on the packaging but were found in significant amounts. What’s not known is whether products from sheep and goats were intentionally added as bulking agents or were accidentally introduced during the manufacturing process.
This traditional Chinese medicine also contained 13 different families of plants that were not declared. Clearly, the manufacturer’s claim of 100% Saiga antelope horn is false.
The dangers of plants
Unravelling the origins of the plants within traditional Chinese medicines represents a more challenging task than the identification of animals. This is because of both the sheer number of species used and the fact that plant DNA databases are a work in progress.
Within the 15 traditional Chinese medicines we tested, we detected 68 distinct families of plants encompassing scores of plant species. Clearly these products are complex blends of plant material – perhaps more complex than manufacturers realise, and certainly more complex than what’s declared on the list of ingredients.
Of particular concern to consumers is that some of the traditional Chinese medicines contained undeclared Ephedra and Asarum species. These plants can contain chemicals that are toxic in the wrong dose – but none of products with them actually listed a dose.
Plants in the genus Asarum often contain Aristolochic acid, a known nephrotoxin (damaging to the kidneys), hepatotoxin (damaging to the liver) and carcinogen. Research published this week provides strong evidence of the link between Aristolochic acid in herbal medicines and the high incidence of urinary tract cancers in Taiwan.
To complement our genetic identification of Asarum, we conducted a metabolomic audit (capable of detecting chemicals in the traditional Chinese medicine) in a product labelled “laryngitis pills”. We were able to confirm the presence of Aristolochic acid.
We also detected the presence of DNA from the soy and nut families of plants, which may be of concern to consumers who have allergies. And again, the plants were not declared in the ingredient list of the products.
Concerns for consumers?
The issue of undeclared constituents has implications for consumers with religious beliefs or cultural practices (such as vegetarianism) that prohibit the eating of certain substances. Tianbao pills, for instance, contained cow DNA, and taking these pills may violate religious or cultural strictures (for instance, Hindus).
This problem is likely to grow as traditional medicines are increasingly being used by an ever wider cross-section of Australian society.
It’s manifestly obvious that herbal medicines should be carefully evaluated for legality, accurate disclosure of ingredients and pharmacologic activities. We advocate for the development and uptake of a combined genetic and metabolite auditing program to improve consumer safety.
Such a program could help regulate the herbal medicine market and, if implemented, would put manufacturers and importers on notice to accurately declare contents of traditional Chinese medicines and other CAM.
There’s a commonly held belief that because CAM are “natural”, herbal remedies, they’re healthy. This is clearly not so, and nor does it necessarily follow that traditional medicines are safe because they have a long history of use.
A recent opinion piece in the journal Nature said, “if TCM is to take its place in the modern medicine cabinet, then it must develop ways to prove itself”.
We concur and believe it applies to all herbal medicines. What’s more, it’s applicable to questions of efficacy, labelling and safety.