The reality of herbal supplement contamination

little-guy2Adulteration of herbal products is common and a threat to consumer safety.

Researchers from Canada and India are the latest to investigate the integrity of herbal products.

First, the details.

  • DNA barcoding was used to conduct a blind test of the authenticity for the following products.
    • 44 herbal products representing 12 companies and 30 different species of herbs
    • 50 leaf samples collected from 42 herbal species
  • DNA barcoding is a technique for characterizing species of organisms using a short DNA sequence from a standard and agreed-upon position in the genome (hereditary information).

And, the results.

  • DNA barcodes were recovered from 91% of herbal products and all leaf samples.
  • 59% of the products tested contained DNA barcodes from plant species not listed on the labels.
  • Almost half (48%) of the products were authenticated, and one-third of these also contained contaminants and or fillers not listed on the label.
  • Product substitution occurred in 30 of 44 of the products tested.
  • Only 2 of 12 companies had products without any substitution, contamination, or fillers.
    • Some of the contaminants pose serious health risks to consumers.
  • One product labeled St. John’s wort contained a laxative called Senna alexandrian, which can cause chronic diarrhea, liver damage, and other problems.

The bottom line?

The authors concluded, “Most of the herbal products tested were of poor quality, including considerable product substitution, contamination and use of fillers. These activities dilute the effectiveness of otherwise useful remedies, lowering the perceived value of all related products because of a lack of consumer confidence in them.”

This is a chronic problem in the herbal supplement industry, as discussed here, here, and here. The widespread and persistent contamination of herbals indicates that manufacturers don’t care or are not qualified to produce medicine for the public.

We need to stop thinking that these products are “natural” and, accordingly, safe.

The authors recommend that the herbal industry should embrace DNA barcoding for authenticating herbal products through testing of raw materials used in manufacturing products.

On there own, the chances of that are slim and none.

10/17/13 21:59 JR

Hi, I’m JR

John Russo, Jr., PharmD, is president of The MedCom Resource, Inc. Previously, he was senior vice president of medical communications at, a complementary and alternative medicine website.