Herbal Testing Twilight Zone: DNA Not a Valid Method


The cardinal rule for testing is methods…

An Op/Ed piece from Elan that was first published on: Today’s Practitioner

It would have been difficult to miss news coverage recently about the New York Attorney General’s evaluation of herbal products from four major store brands with DNA barcode testing. As a chemist and CEO of Alkemist Labs, a widely respected third-party analytical testing lab dedicated to testing natural products, it felt like the Twilight Zone as I watched this unfold. Within seconds of reading the testing methodology, it was clear the methods were not valid. DNA testing works for crime scenes and to identifying mislabeled whole foods, but it does not work for herbal extracts.

The tests concluded that the majority of the products contained no herbs but did contain other substances that were not on the label. The AG demanded Wal-Mart, Walgreens, GNC and Target cease and desist selling those products. The New York Times, working with the NY AG in advance, broke the story, which was then picked up by news outlets throughout the US and some international media outlets. Both the Times and the NY AG then doubled down on their conclusions, with the newspaper calling for dietary supplements to be regulated like drugs and the AG second-guessing the FDA on structure function claims by demanding substantiation from the four companies.

By the end of 10 days, consumers were losing confidence in dietary supplements in general, solely based on this report. So what are the facts – can herbal products be trusted? And should you use them in your practice?

The cardinal rule for testing is methods: 1) Are they valid? In other words, are they universally accepted as providing reliable results, and, 2) Are they fit for the intended purpose, meaning are they appropriate for the material being tested? DNA testing is very reliable for some purposes, such as crime scene analysis or to insure that fish is accurately labeled for its species. It can also identify raw unextracted or unprocessed botanicals like Ginkgo biloba. But it cannot test finished herbal products, which the AG office should have known. This incidence shows how little is understood in the science, government and legal community about how herbal products are tested.

Above all, barcode testing accuracy depends upon whether there is actually DNA present to detect, which was not the case in this instance. If the person in charge of the DNA testing in question had been an expert in botanicals and not an evolutionary biologist specializing in reptiles and dinosaurs, we would have never entered this fifth dimension of absurdity.

I have no doubt that James A. Schulte II, PhD, of Clarkson University in Potsdam, New York, is quite adept at his chosen field of evolutionary biology and reptilian zoology, but he is not an expert in botany and pharmacognosy. Even the FDA has gone on record as saying that DNA barcode testing is not an appropriate method for herbal extracts.

Here is why DNA testing is not the correct methodology: when herbs are extracted, specific desired constituents of the herb are removed from the raw plant by various methods, all of which denatures or nearly removes the previously present DNA. This is why validated testing methods exist – to identify the desired material with the right test.

A strategic combination of high performance liquid chromatography (HPLC) fingerprint analysis or high performance thin layer chromatography (HPTLC) will cover the bases of identity testing in finished herbal products. While they do have some limitations, these methods have stood the test of time and are accepted by government agencies like FDA, Australia’s TGA and Health Canada, among many others. In my experience, these tests work extremely well in the hands of specifically trained technicians who are committed to accurate results.

As was reported in the NY Times, the tests results found powdered rice, beans, peas and wild carrots, as well as unlisted powdered legumes. DNA testing does not identify quantities, just presence. All of these substances are commonly used as excipients, with well-established legal thresholds allowing for trace amounts without the need to be labeled as such.

I can tell you that as one of the leading botanical testing labs, we do see some quality issues and some adulteration. However, we do not see failure rates like the ones outlined by the NY AG. In fact, I can honestly say industry quality has been getting better year after year.

If anything, this round of negative media coverage, based upon what my colleagues and I believe to be flawed science, tells us there is a greater need for testing transparency. Companies can no longer afford to just say their products are tested. They are going to have to reveal where they are tested, by what methods, and why. Based upon what our company is hearing, that will happen.

For the practitioner, should you continue to provide or even recommend botanical products to your patients?  Based upon this recent controversy, I can only say that if you were comfortable with them last week, nothing the New York Times reports should change your mind.

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