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 desists 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
on 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 bar coding 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 was from the root or the leaf and 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 U.S. Pharmacopial Convention (USP) writes
that tests such as chemical analysis are better suited for this instance
because it detects the quantity of a material as opposed to 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 in order 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 bar coding in regards
to ingredient identification. Lipp mentioned that these fillers are often added
after processing and are not subject to the harsh handling. Ultimately, the
officials from USP were happy that the government was taking an active role to
fight 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.

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