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GNC's agreement to utilize DNA testing on herbal ingredients prior to extraction has drawn criticism from CRN and others, but an appropriate use of the method does offer certain advantages.
The appropriate usage of DNA barcode testing on dietary supplements has taken center stage in the debate surrounding New York State Attorney General (NY AG) Eric T. Schneiderman’s investigation into herbal supplements, but this week’s agreement between the NY AG and retailer GNC may have finally found the proper use for the technique, according to one DNA testing expert. Although many aspects of the agreement have drawn criticism from industry associations and leaders, the idea of GNC utilizing DNA testing on ingredients prior to extraction does offer certain advantages, says Danica Harbaugh Reynaud, PhD, CEO, AuthenTechnologies LLC.
On February 2, Schneiderman ordered herbal supplement products pulled from the shelves of four retailers, including GNC, as a result of DNA barcode testing commissioned by the NY AG’s office. The testing purportedly discovered that the products’ ingredients did not meet label claims, but CRN and other industry associations have called out the NY AG for inappropriately applying DNA barcode testing to extracts and finished products.
According to a white paper written by DNA experts, including Reynaud, in March and commissioned by dietary supplement industry trade association the Council for Responsible Nutrition (CRN; Washington, DC), “Typically, most, if not all, of the material containing cells (with the DNA) is removed during extraction, leaving the phytochemical but not the DNA. Any DNA that does remain in a botanical extract is generally low in quality and concentration.” Most botanical dietary supplements contain extracts and not raw materials, suggesting that DNA barcode testing is not the right technique for authenticating finished products.
Although the NY AG has not released the complete methodology of the investigation, the authors of the white paper wrote: “We can assert confidently that the [NY AG’s] conclusions-that a majority of supplements lacked any botanical at all-based only on the results of DNA barcoding tests were unjustified.”
DNA Testing the Right Way
But this week’s news of the agreement between GNC and the NY AG has at least one of the white paper’s authors excited to hear that GNC will begin implementing DNA authentication testing on ingredients prior to extraction. Reynaud, whose firm, AuthenTechnologies LLC, is a DNA botanical authentication testing company, says she was happy to hear about this aspect of the agreement. She “absolutely” finds it to be the proper application of DNA barcode testing.
“I think it’s a great idea. We’ve been pushing for that for all of our clients for years,” says Reynaud. “I think DNA does something that other tests don’t, which is find unexpected adulterants, things like allergens and other contaminants and plant material or other biological materials that you might not be testing for with other methods. Typically chemical tests are limited in that they are looking for either target molecules or target species and aren’t as equipped for identifying unexpected adulterants or differentiating between closely related species.”
In their white paper, Reynaud and coauthors do, however, point out that in order for DNA testing to be done correctly, those performing DNA barcoding need to have an extensive and experienced understanding of plant species and DNA testing, and that a single set of genes may not be enough to adequately differentiate species. They also state that scientists need to test a significant number of samples and genes of a species to rule out false positives and negatives.
Still, with allergen contamination in particular, which the NY AG has referenced as one of the greatest concerns driving his investigation, DNA testing is an easy way to identify lots of different allergens at once rather than testing for each one individually, says Reynaud.
Integrating DNA testing into raw material verification isn’t an especially costly venture either, says Reynaud, because testing costs are roughly comparable to other methods.
“In the end I think [manufacturers] end up saving money because, especially if you’re testing the raw materials before it’s been extracted and put into a product, you can eliminate bad batches before you even make the product so you don’t have to deal with adverse events or these sorts of class-action lawsuits,” says Reynaud. “I think it becomes a very affordable preventative measure.”
In certain circumstances, DNA testing might even be an effective replacement for other chemical testing methods, she contends.
“If the claim is just that you have a particular species and it’s a leaf versus a root or what have you, DNA [testing] plus morphology is really all you need,” says Reynaud. “If you’re making claims that there’s a particular compound or a certain potency of a compound, then obviously you would need chemical analysis as well. But I think in a lot of cases it could be used as a replacement for certain types of identification methods.”
She also points out that all testing methods, including those based on DNA, have a higher degree of certainty in authenticating species and detecting adulterants in raw materials rather than finished products.
The NY AG/GNC agreement also stipulates that GNC will contribute any DNA barcodes it identifies to a publicly accessible database. Industry members, as well as Reynaud and her white paper coauthors, cite lack of robust DNA reference libraries as one current challenge to applying DNA testing industrywide, with Reynaud and the white paper authors pointing to how lack of current reference standards may have negatively affected the NY AG's own investigation: “Most of the species under investigation by the NY AG cannot be accurately identified without a proprietary database of reference standards, as several of the species under investigation-including St. John’s wort and Echinacea-do not have publically available reference sequences from the genes necessary to identify them….This is clearly an issue with the NY AG’s study, which provided highly ambiguous results, including reports of identifying Allium (which includes both onion and garlic), as well as legumes (which constitute a wide range of species including soy and pinto beans), as well as houseplant (which could be any number of things),” they wrote.
In the case of the GNC and NY AG's agreement, Reynaud says she is skeptical of how thorough or effective this database could really be in order to achieve complete DNA sequencing data for most commercially used herb species. She says it would take years and millions of dollars to construct one-something that’s likely well beyond the scope of what GNC has agreed to do.
Industry Associations Still Opposed
Even with the shift to DNA testing of raw materials rather than finished products in the GNC/NY AG agreement, industry associations and leaders remain deeply critical of GNC’s concession to use DNA testing.
“I think it’s bad for consumers as well as industry because it perpetuates the notion that DNA barcode testing is appropriate for dietary supplements,” said Steve Mister, president and CEO, CRN, in a previous Nutritional Outlook interview. Mister said that the GNC/NY AG agreement does seem to imply that the AG’s office is retreating on its earlier position of using DNA testing on finished products because the agreement specifies that GNC will apply DNA testing to raw material, not finished extracts.
“[The NY AG] is not admitting it, but the fact that they’re only going to require it on the raw materials-I don’t see how else you can read that except that it’s an admission that they got it wrong,” Mister said.
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Edited 4/6/15 7:25 AM PST
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