Researchers at Ontario’s University of Guelph have come up with some surprising, and worrisome, information on what goes into so-called “natural” herbal products and medicines. Their research will be published today in the online journal BMC Medicine
“Some of the contaminants we found pose serious health risks to consumers.” (BMC Medicine abstract)
They blind tested some 44 products (42 capsules, 2 powders, 1 tablet) from 12 companies and 30 species of herbs. As a verification of the DNA testing of the medicines, they also tested 50 leaf samples from 42 herbal species from known provenance.
In testing the medicines, they found that in many cases labels on the products did not indicate fully what was in the product.
Perhaps not so surprisingly they found many products contained fillers such as rice, soybean, wheat or alfalfa, not mentioned on the label, and which could possibly pose allergic reactions. Others contained traces of plants with toxicity or other allergic concerns. Another example was a ginko product contaminated with black walnut which could cause reactions in those with nut allegies.
In fact, 59 % of the products tested contained contaminants or fillers not listed on the container.
It says ginkgo biloba . . . and we didn’t find any ginkgo DNA at all in the bottle,” integrative biology professor and lead author Steve Newmaster
The authors also say that most of the products were of poor quality with only 2 of the 12 company products tested had products with no contamination, substitution, or fillers.
Professor Newmaster is the botanical director of the Biodiversity Institute of Ontario, which is the home of the Canadian Centre for DNA Barcoding. He says, “ People buying herbal products need to know they may not be getting what they are paying for — and they may be ingesting something they aren’t expecting.”
A 2010 Ipsos Reid poll done for Health Canada found that 73 per cent of Canadians admit to using natural health products of some sort. Conversely, half expressed som skepticism about the health claims made by manufacturers and over 40 percent were dubious about product quality.
In spite of such apparent misgivings, people routinely self-prescribe natural health products. Doctors routinely ask patients to advise them if they are taking herbal remedies, which are chemicals, due to potential reaction with prescription drugs.
This new study raises concerns about the ability to avoid certain known potentially serious drug-herbal interactions.
The World Health Organization calls adulteration of herbal products a threat to consumer safety.
Provisional report “DNA barcoding detects contamination and substitution in North American herbal products“
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