What’s in Chinese Medicine? New DNA Study Finds Some Unpleasant Answers.

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.


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4 Responses to What’s in Chinese Medicine? New DNA Study Finds Some Unpleasant Answers.

  1. Linda says:

    I agree with there are huge labelling issues with Chinese products in general. They do that with food products too. It’s annoying to pick up a packet of sweet potatoes that obviously has sugar in it only to see it say ‘sweet potatoes’ for ‘ingredients.

    However, of course.. I do not agree with the part where you say that there is ‘…no reasonable evidence to suggest the inclusion of these ingredients has any actual health benefit. Sympathetic magic and other mythological foundations’ – I don’t believe there are any studies that have proven either way, so I don’t know if it should really be that ‘infuriating’.. In any case, even if there was a health benefit, I don’t believe that we as humans should hunt anything to extinction, especially when there are always alternatives.

  2. skeptvet says:

    Well, as I said in my earlier response, I see no evidence that the system of metaphors underlying the TCM approach has any correlation to reality. Yin/Yang, the Five Elements and so on have never been demonstrated to exist or have anything to do with health, and the only basis on which they are accepted as explanations and guidance for therapy is blind faith in tradition and the experience of individuals who claim to have seem benefits from this approach. The exact same things, tradition and personal experience, supported thousands of years of bloodletting based on the notion of vital humours in the West, and every other set of metaphors and folk healing practices ever invented. And yet none of these have consistently deomnstrated their value in objective testing nor had the enormous impact on human health and longevity of medicine based on science, so the idea that they ought to be treated as equally valid ways of understanding health and disease makes no sense.

  3. Art says:

    Linda,, can we agree that There is no proven evidence? My belief system gets in the way when I try to practice Reasonable medicine without the clients help to define what is reasonable. Do you think that it is reasonable to assume that unproven medicine is more likely to harm than help? Sort of like playing the lottery where you can win sometimes but usually loose
    Art Malernee dvm

  4. Pingback: The Harm Complementary and Alternative Medicine Can Do | The SkeptVet Blog

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