DNA Barcode Testing: Does it Work for Dietary Supplements?

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DNA Barcode Testing: Does it Work for Dietary Supplements?

In February of this year, the New York State Attorney General’s Office investigated major retailers for selling dubious and potentially dangerous herbal supplements, according to the New York Times. They targeted Walgreens, Target, Walmart, and GNC, all well-known big-box retailers that generally sell safe products. The authorities said that they had tested the herbal supplements and that they were
mostly unable to find any trace of the herbs in the products, leading them to believe that these supplements were fraudulent.

So, how did they come to that conclusion? The authorities noted that the products contained fillers like powdered rice, carrots, asparagus, and other substances but could not positively identify a supplement such as St. John’s Wort or Echinacea. Labels that did reflect fillers did not indicate the amount. They were mostly concerned with the labels not accurately reflecting allergens that might harm consumers.

Thus, the state attorney general, Eric T. Schneiderman, issued cease and desist to these stores on the basis of mislabeling and false
advertising, violations of the law that open up these stores to liability, and potential lawsuits.

The Food and Drug Administration (FDA) does not require supplements to follow the strict approval process for prescription drugs, but
they do require companies to verify that the supplements are accurately labeled.

Proposals from lawmakers over the years have sought to tighten regulations, but few have been successfully passed. An amendment
proposed in 2012 that would require supplement manufacturers to register with the FDA and provide extensive information about their ingredients was struck down.

Dietary supplements have not been without controversy in recent times, especially in regards to their health risks.

Dr. Pieter Cohen of Harvard Medical School expressed doubt about the findings because of their extremeness. According to state officials, some supplements did not turn up any DNA from herbs through the test – DNA barcoding.

What is DNA barcode testing?

This test identifies an organism using a segment of its mtDNA – better known as mitochondrial DNA. It was invented by a biologist at
the University of Guelph named Paul Herbert in order for scientists to quickly identify unknown species by taking a sample of its DNA, amplifying it (making it easier to read), and matching it against a database. While the database has a
library of bar codes corresponding to 150,000 known animals and 60,000 plants, there are about ten to one hundred million species on Earth. The test was also performed by Beckman Coulter Genomics and a Clarkson University biologist named James Schulte. James is a specialist in snake and lizard evolution.

What happened?

DNA barcoding is a fairly recent testing innovation and not an exact science. While scientists and researchers have relied on this
technology in order to identify species of fish or trees, identifying the presence of an herb can be difficult or misleading. For example, the DNA test could identify Ginkgo in a supplement but not where the Ginkgo came from because the DNA is the same, whether it is from the root or the leaf. It cannot distinguish if the plant was grown in ideal environmental conditions.

The other issue is that these herbs are found in different extracted forms, and their DNA is destroyed when mixed with solvents, heat, or another refinement process. Other tests are required to validate these herbal supplements, as noted by another New York Times article.

Dr. Nandukumara Sarma of the U.S. Pharmacopeial Convention (USP) writes that tests such as chemical analysis are better suited for this instance
because it detects the quantity of material instead of DNA barcode testing that tracks the quality of the DNA and opines that the New York Attorney General’s office should have used a wide array of tests to achieve the most accurate results.

The Senior Director of USP, Markus Lipp, also noted that Schulte’s team did not take into account that processing can destroy a plant’s
genetic material, but the plant still retains its health benefits. Fillers are also permitted as long as they do not exceed a certain level.

Though there is fraud in the dietary supplement industry, this would not fit the description based on what had unfolded. Nicola Twilley,
the author of one of the articles cited in this post, reached out to the Attorney General’s office and received a lukewarm welcome. An anonymous representative argued that it did not make sense that rice or other fillers would show up in the scan and not the DNA of the purported herb and that numerous published studies have shown the efficacy of DNA barcoding in regard to ingredient identification. Lipp mentioned that these fillers are often added after processing and are not subject to harsh handling. Ultimately, the officials from USP were happy that the government was taking an active role in fighting fraud, albeit missing the mark in this case.

It is ironic that the body that certifies ingredients for supplements (USP) would opine that the state attorney’s office would use DNA
barcode testing as opposed to the array of tests laid out by USP.

To read more about this, check out the two articles used for this post by clicking here and here.