Herbal Supplements Often Don’t Supplement

Dietary supplements are big business. A 2013 study from the Canadian Institutes of Health Research estimated there are about 65,000 dietary supplements on the market consumed by more than 150 million Americans.

The FDA defines a dietary supplement as a product taken by mouth that contains a “dietary ingredient” intended to supplement the diet. Unlike pharmaceutical products, the law does not require dietary supplements to undergo stringent review by the FDA before they are marketed. However, the FDA does mandate that manufacturers of supplements use good practices to ensure quality throughout the manufacturing, packaging, labeling and storing of these products. But dietary supplements adulterated with pharmaceutical compounds have continued to enter the marketplace.

Now, the New York Attorney General's office has warned GNC, Target, Walmart and Walgreens to stop selling many common store-brand herbal supplements after DNA tests found that many did not contain the ingredient listed on the product's label or contained contaminants or fillers not included on the label. The results were far from occasional or scattershot: just 21% of the test results from store-brand herbal supplements indicated that the supplements had DNA from the plants listed on the labels without unlisted contaminants.

Supplements have always been embattled to a certain degree, struggling to prove many of their health claims and to avoid the modifier “dubious.” But, as the Center for Science in the Public Interest website states succinctly, “[W]hen the advertised herbs aren't even in many of the pills, it's a sign that this poorly regulated industry is in desperate need of reform.”

Walmart fared the worst, with only 4% of the tests indicating that the product contained DNA from the advertised plant. At each retailer, the investigation looked at six commonly advertised (and sought after) herbal supplements, for example, St. John's wort, ginseng and echinacea.

None of Walmart's Spring Valley line of echinacea contained DNA evidence of the herb, according to the report, which prompted letters to the four major retailers. In addition to calling upon the retailers to immediately stop selling these and other popular herbal supplements, the office of Attorney General Eric Schneiderman asked them to provide detailed information “relating to the production, processing and testing” of herbal supplements sold at their stores, and to deliver a thorough explanation of quality control measures in place.

DNA testing was performed as part of an ongoing investigation by the Attorney General’s Office, and revealed that 79% of the store-brand supplements either tested completely negative for DNA related to the labeled content, or verified contamination with other, filler plant material.

The investigation used DNA barcoding technology to examine the contents of the herbal supplements sold at the four major retailers in 13 regions across the state, including Binghamton, Brooklyn, Buffalo, Harlem, Nassau County, Plattsburgh, Poughkeepsie, Rochester, Suffolk County, Syracuse, Utica, Watertown and Westchester County.

DNA barcodes are short genetic markers in an organism’s DNA and are used to identify it as belonging to a particular species. Barcodes provide an unbiased, reproducible method of species identification.

The DNA tests were performed on three to four samples of each of the six herbal supplements purchased from the New York stores. Each sample was tested with five distinct sequence runs, meaning each sample was tested five times. Nearly 400 tests involving 78 samples were performed overall.

While overall 21% of the product tests confirmed DNA barcodes from the plant species listed on the labels, 35% of the product tests identified DNA barcodes from plant species not listed on the labels, representing contaminants and fillers. A large number of the tests did not reveal any DNA from a botanical substance of any kind. Some of the contaminants identified include rice, beans, pine, citrus, asparagus, primrose, wheat, houseplant and wild carrot.

In many cases, unlisted contaminants were the only plant material found in the product samples.

A logical next step is to require labeling that clearly indicates whether a product has undergone FDA testing, and such a measure is currently being sponsored by at least one New York State senator. That requirement would remind people that supplements are not pharmaceuticals.

Still, if the producers of herbal supplements fail to identify all the ingredients on a product’s label, a consumer with food allergies or one who is taking medication for an unrelated illness is at potentially serious health risk every time a contaminated herbal supplement is ingested. The Attorney General's investigation is therefore focused on the possibility of violations of New York's General Business Law and Executive Law, which includes deceptive practices and deceptive advertising. 

Office of Eric T. Schneiderman, Press Release, Feb. 2015, http://www.ag.ny.gov/press-release/ag-schneiderman-asks-major-retailers-halt-sales-certain-herbal-supplements-dna-tests

JAMA Intern. Med., 2013, Vol. 173, No. 10, pp. 929-930, doi:10.1001/jamainternmed.2013.379

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