The lack of effective regulation covering herbal remedies and dietary supplements is well-known. The General Accounting Office has warned Congress about the widespread deceptive and illegal marketing of such remedies. And there are numerous studies which illustrate the potential dangers of unregulated and inadequately tested herbal products. Apart from the issues that such remedies are often put together on the basis of unscientific mythological understandings of health and disease, or that they are marketed on the basis of the naturalistic fallacy, the notion that such remedies can be viewed as “natural” and so are automatically safe, and that they are seldom rigorously evaluated through adequate pre-clinical and clinical trial testing, one big problem with herbal and other Chinese Medicine products is that practitioners and patients often don’t even know what they contain.
For example, I’ve written previously about Yunnan Paiyao, which is supposed to control bleeding, both topically and systemically. Many preparations of this product don’t even list an active ingredient. I cannot imagine most people being willing to take a medicine when the manufacturer refused to disclose the ingredients, but the same sensible caution doesn’t always seem to be applied to herbal products.
Of course, many Traditional Chinese Medicine products do list their ingredients, but given the problems with label accuracy for other unregulated alternative remedies, such as probiotics, some skepticism about the accuracy of these labels seems warranted. An objective method for determining what such remedies actually contain would be a good start in evaluating their quality control and the potential for harm from undisclosed ingredients.
Some studies have looked at chemical components, including undisclosed pharmaceuticals and heavy metals. A recent pilot study has taken a different approach, trying to identify the plant and animal ingredients through identification of DNA found in the products.
Coghlan ML. Deep sequencing of plant and animal DNA within traditional Chinese medicines reveals legality issues and health safety concerns. PLOS Genetics. 2012;8(4):e1002675.
The authors looked at 28 samples of TCM products seized by the Australian customs service and were able to identify plant and animal components of 15 products. One of the methodological problems with this approach is that databases of DNA sequences, particularly for plants, are not yet sufficiently extensive to allow precise species-level identification of many plants. However, these databases are growing rapidly, and the precision of this technique is likely to be excellent as the reference resources improve.
Examples of the usual sorts of concerns did surface in the study. Plants with known toxic properties were identified in 4/15 samples, including Ephedra, and Asarum, a potential source of aristolochic acid, which is a TCM ingredient known to cause kidney failure and urinary tract cancer. The authors did not evaluate the samples to determine if these toxins were actually present, though they indicated that combining such standard chemical analysis with their DNA sequencing approach would be the optimal way to evaluate such products.
The study also identified DNA from known endangered species of both plants and animals, including bears and Saiga antelope. TCM remedies made from parts of endangered species are a significant environmental problem which is particularly infuriating since there is no reasonable evidence to suggest the inclusion of these ingredients has any actual health benefit. Sympathetic magic and other mythological foundations for such practices are not legitimate reasons to contribute to the threats to endangered animal and plant species.
Finally, the study identified significant mislabeling. 78% of the samples contained DNA for species of animals not listed on the label. Sheep, goats, water buffalo, and cows were found, among other species, and these likely represent adulteration with cheaper, easier to acquire ingredients replacing traditional ingredients such as those from bear and Saiga antelope. While this may reduce the risk to such endangered species, one can hardly approve of substituting animal products with no demonstrated health effects for other animal products with no evidence of health benefits and then not even honestly labeling the products.
Though this particular study looked at a very limited selection of remedies and only identified a relatively small set of ingredients, it demonstrates both that such methods can be useful in identifying the true constituents of TCM products and also that these products can contain ingredients that are toxic, that come from endangered species, or that aren’t listed on the labels. Such problems aren’t likely to improve without meaningful regulations requiring thorough and accurate labeling, independent monitoring of compliance with label regulations, and ideally requirements for reasonable evidence of safety and efficacy before the products can be marketed at all. Unfortunately, none of these sensible requirements seem likely to be put in place any time soon.