With the help of researchers who put together herbal DNA barcodes, PBS NewsHour’s Paul Solman found out just how often the actual contents of herbal supplements don’t jive with the words on their labels.
Black cohosh. Photo by Shotaku via Flickr
To make his point, Solman zeroes in on black cohosh, a herb used by some women to treat the symptoms of menopause. In a 26-brand sample, researchers found that 30 percent of the preparations labeled “black cohosh” contained absolutely nothing that could be identified. Apparently, cohosh looks quite similar to many other (non-theraputic) plants in its family. As Dennis Stevenson – the botanist behind the DNA labeling – told Solman, it’s not easy to identify:
Black cohosh is one of these plants that’s collected in the wild and only – if I’m not a trained botanist, I go out: “Oh, it looks like cohosh. I will get a bunch of it and sell it to the supplier, and – and we’re all happy.”
It’s not just the confusing herbs that prove problematic, though, Solman finds. He convinced the lab to test samples he provided of cohosh, ginkgo and ginseng, producing a small but illuminating sample of the mislabeling that appears common in the industry.
Admittedly, our sample size was too small to be statistically significant. But, surely, all the ginkgo would be ginkgo; ginseng, ginseng. And the lab agreed to do the test, so why not?
The results, also reported anonymously. Get this: Only two of our four ginseng samples seemed to contain ginseng, and even that was the Asian species, not the preferred North American variety. The other two contained some complex mixture of DNA, none of which could be confirmed as ginseng.
The four supposed samples of the ubiquitous, unmistakable ginkgo tree? One was legit, another an exact DNA match for common rice, the third a complex mixture of DNA, none of which, the lab report said, resembled ginkgo biloba DNA, and the fourth contained no plant DNA at all.
Our black cohosh samples did better. Seven out of eight did contain the plant, but one didn’t. Of 16 supplements, then, bought at random from major retailers in the Washington, D.C., area, six were suspect or outright frauds, prompting one last question for Dr. Baker.
One caveat: While research on the effectiveness of herbal supplements like cohosh can produces inconsistent results, an official with the National Center for Complementary and Alternative Medicine says blame doesn’t fall on unreliable supplies, at least in the tests his agency has overseen.
(NCAM’s Dr. Jack Killen) says he’s sure his samples were authentic:
“So, I think we have a great deal of confidence that the variability that we see in the research is not attributable to ‘sometimes the black cohosh is there and sometimes it isn’t.'”
Other video highlights to watch for: How many herbal teas are cut with chamomile. Or grass clippings. Also, the lack of government regulation in the industry.