Not long ago I was posting on how DNA Barcoding can help to ensure the quality of ingredients of traditional Chinese medicine. Two new studies corroborate this once more and cast some doubt on Natural Health Products in general.
Natural Health Products are often considered safe due to their natural origin, however, adulterated, counterfeit and low quality products pose serious safety threats to consumers. In some countries such as the U.S., unlike drugs, they are not required to be tested for safety or efficacy before they hit the market. Furthermore, testing to make sure the contents match the label are much more lax than it is for pharmaceuticals, opening the opportunity for mislabeling, whether it is accidental or intentional.
One study conducted here at the Biodiversity Institute of Ontario consisted of tests on 95 plant and animal products bought in Toronto and New York City. The sampling included a variety of products such as capsules, tablets, roots, extracts, teas and shredded products. Of the 26 animal DNA Barcodes obtained, 21 correctly matched their commercial label. The remaining five were either cheaper alternatives or fragments of protected species such as some sharks.
Half of the plant products labelled as Korean ginseng (Panax ginseng) were in fact American ginseng (Panax quinquefolius) which is cheaper and is sold for different medicinal benefits. More concerning is one case were a product labelled as Echinacea (Echinacea purpurea), closely matched species from the walnut family (Juglandaceae). Bad news for people with nut allergies.
Study number two comes from New York City and provides a more focused look at a herbal menopause supplement. Black cohosh (Actaea racemosa) is a consumer favorite especially since hormone replacement therapy was found to put some women at increased risk of cancer and cardiovascular disease. However, controlled trials with the popular remedy showed mixed results. Sometimes it had been effective in the treatment of menopause symptoms whereas other times it was revealed to be ineffective, and a few cases even suggested that it can be toxic. The researchers found that 25% of the 36 dietary supplements tested were in fact members of three Asian Actaea species. By the way the study described above also contained such a case.
This might explain the contradictory results in the clinical trials. Reasons could be variation in the concentration of black cohosh, adulteration that affects the action of the active ingredients, or even harmful compounds.
Two more studies that unfortunately tell us that no matter what and where you buy you cannot always be sure you get what the label on a product says. The good news is that with DNA Barcoding we have an instrument that could put an end to this.