“Herbal” Supplements Often Not as Advertised

Patients may ask about a study concluding that herbal supplements might not be as herbal as advertised. The findings, published in BMC Medicine, got front-page coverage on the New York Times website.

Using DNA analysis, researchers tested the authenticity of 44 products from a dozen companies. The DNA signatures were compared with samples obtained from horticultural greenhouses.

The result? More than half the products contained plant species not listed on the label, and one third had a product “substitution” (the advertised ingredient was not even present). One product labeled as St. John's wort actually contained senna — a laxative. A ginkgo product was contaminated with a tree nut — dangerous for people with nut allergies. Another contamina…