05 November 2013

DNA testing reveals fake "herbal supplements"

As reported in the New York Times:
Using a test called DNA barcoding, a kind of genetic fingerprinting that has also been used to help uncover labeling fraud in the commercial seafood industry, Canadian researchers tested 44 bottles of popular supplements sold by 12 companies. They found that many were not what they claimed to be, and that pills labeled as popular herbs were often diluted — or replaced entirely — by cheap fillers like soybean, wheat and rice.
Consumer advocates and scientists say the research provides more evidence that the herbal supplement industry is riddled with questionable practices. Industry representatives argue that any problems are not widespread. 

For the study, the researchers selected popular medicinal herbs, and then randomly bought different brands of those products from stores and outlets in Canada and the United States. To avoid singling out any company, they did not disclose any product names. 

Among their findings were bottles of echinacea supplements, used by millions of Americans to prevent and treat colds, that contained ground up bitter weed, Parthenium hysterophorus, an invasive plant found in India and Australia that has been linked to rashes, nausea and flatulence. 

Two bottles labeled as St. John’s wort, which studies have shown may treat mild depression, contained none of the medicinal herb. Instead, the pills in one bottle were made of nothing but rice, and another bottle contained only Alexandrian senna, an Egyptian yellow shrub that is a powerful laxative. Gingko biloba supplements, promoted as memory enhancers, were mixed with fillers and black walnut, a potentially deadly hazard for people with nut allergies...
Of 44 herbal supplements tested, one-third showed outright substitution, meaning there was no trace of the plant advertised on the bottle — only another plant in its place. 
More at the link.


  1. The assholes they have been doing this for a long time only buy from the good guys

  2. I am a pharmacist and a Ph.D. researcher of botanical dietary supplements. One important thing to note about that study is that they needed DNA from plant material, which meant they only chose companies that put leaf/plant material in a pill. There is no ethonobotanical evidence to suggest that the small amount of leaves that fit into a pill will be efficacious in any way. I strongly advocate against these companies as inferior products (if you read on the label, 200 mg of "plant name", without the word "extract" or "standardized to" followed by a compound name, you should not buy it. The good companies have high quality plant material, some go to great lengths, and do very good quality control and make standardized extracts which are concentrated of biologically active, or maker compounds. I think a good analogy is a cup of tea or coffee - would you be happy with one bean or one tea leaf? Or rather, it seems more like half a bean is what the pills were being diluted down to. That is essentially what they are putting in the pills which are very cheap to produce and therefore, highly questionable to begin with, efficaciously, scientifically, and ethically. Very few of the high quality companies do that. However, those good products that are trustworthy are typically more expensive. You get what you pay for. So, this study examined the lowest quality products that I, or other trained professionals, would never recommend to begin with. Ones with standardized, high quality extracts, would not have plant DNA material in them, so, they were automatically excluded from this study. I have personally examined some products that have standardized extracts or high quality ethanolic extracts using LC-MS and they have what they say they have in adequate concentrations for efficacy. So, I am disappointed that this study is highlighting the worst and getting a lot of press and leading people to generalize all BDS as if these were representative.

    1. That's a very interesting observation. From your comment "Ones with standardized, high quality extracts, would not have plant DNA material in them" I would infer that plant DNA is broken down or somehow denatured during the extraction process. That being the case, how does one know that the other bioactive/therapeutic components of the living plant are not also damaged during the processing?

      Apparently digitallis is/was effectively extracted from foxglove, so that administration of "leaf" is no longer necessary, but how does one know which components of St. John's wort are the efficacious entities?

    2. For DNA there are specialized techniques for extracting it intact. For small molecules, that's a good question. There are specialized techniques that companies are optimizing - such as supercritical CO2 extraction that are particularly gentle. But most actives are stable in ethanol and even heat (if not, then caffeine, marijuana, tea, nicotine etc., would not be so popular). Also, if they weren't stable the plant would have to keep producing them - being a huge waste of resources. In my experience they are quite stable. Interestingly, some compounds are not stable once isolated, such as alpha-sanshool - a type of compounds that give hot compounds in Szechuan pepper their heat. In an extract it is just fine - even when I abused it with heat or leave it for a long time in a dilute extract. Once isolated though, it begins to degrade. So, there is definitely added stability other constituents provide (think of why you need to give vitamin E with vitamin C).

      Per St. John's Wort, that one is tricky (which is why you probably asked!) - only now is biology advancing to answer that fully, as you probably know. So, the only way is to use traditional knowledge (Ayurvedic physician's, for example, know how best to extract actives that I've found remarkable - all my trial and error in the lab, they already figured out), quality material, and use marker compounds, compounds that make the plant unique, with a range of them being ideal. This is not optimal and minor constituents can be the actives, not the major ones visible in a crude extract that are used as marker compounds. But one thing I like to remind people when talking about "how do we know it's active", is that we are still figuring out how acetaminophen works! Not to mention that we aren't sure right now which antidepressant works for which person best or if a certain one will work at all for a given individual (but that's a whole complex and different topic) - but demonstrates the complexity of that particular example. A lot more interesting work and good science to be done.

  3. If your going to the trouble and expense of all this testing name the companys and the products,
    hold the feet to the fire. This amounts to nothing but reaffirming want I would expect and assume from the
    greed first ethic of buisness today.

  4. Spending column inches on the history of the science used but never naming the good or the bad companies amounts to doing an attack piece on the entire industry, harming the ethical companies as equally as those deserving harm. I wonder who the author works for?


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