Testing of popular supplements found many contained other than what was on the label, diluted or replaced entirely by inexpensive fillers.
Canadian researchers tested 44 popular supplements from 12 companies, using a process called DNA barcoding, and found soybean, wheat and rice instead of the expensive herbal ingredients consumers expected.
While the researchers declined to identify the specific companies whose products they tested, they discovered 59 percent of products tested contained ingredients not on the label, an issue that is not only dishonest business but a real health concern for people with allergies or dietary restrictions.
Bottles of echinacea supplements contained bitter weed, Parthenium hysterophorus, an invasive plant from India and Australia known to cause rashes, gas and nausea. Gingko biloba pills were found mixed with black walnut and other fillers, potentially deadly to people allergic to nuts.
Fully one third of the tested samples contained none of the herb advertised on the label. Samples meant to contain St. John's Wort had none of the depression-treating herb, with some containing just rice, and others made of Alexandrian senna, an Egyptian shrub with laxative properties.
“This suggests that the problems are widespread and that quality control for many companies, whether through ignorance, incompetence or dishonesty, is unacceptable,” said David Schardt, a senior nutritionist at the Center for Science in the Public Interest, an advocacy group. “Given these results, it’s hard to recommend any herbal supplements to consumers.”
Members of the herbal supplement industry said the problems were hardly widespread, while Stefan Gafner said DNA barcoding may not be able to identify properly labeled herbs that had been processed and purified.
“Over all, I would agree that quality control is an issue in the herbal industry,” said Gafner, the chief science officer at the American Botanical Council, which promotes the use of herbal supplements. “But I think that what’s represented here is overblown. I don’t think it’s as bad as it looks according to this study.”
But a spokeswoman for the Food and Drug Administration, which has rules against "misbranding" supplements but essentially leaves companies to police themselves, said the problem was very real.
“Unfortunately, we are seeing a very high percentage -- approximately 70 percent -- of firms’ noncompliance,” said Shelly Burgess, “and we are very active in taking enforcement actions against such violations.”