Some 3,000 species of plants are sold as herbal supplements in this country in as many as 50,000 different products, the American Herbal Products Association estimates. Figuring out if what's inside any particular package corresponds to the contents on the label is far from simple, according to Joseph M. Betz, director of the dietary supplements methods and reference materials program at NIH.
"Chemistry is the only means of determining the quality of the material," Betz last week told a symposium on challenges in chemical analysis of herbal supplements sponsored by the Division of Agricultural & Food Chemistry at the ACS meeting in Anaheim, Calif. Betz's program supports research aimed at clearing the confusion in the marketplace by validating analytical methods and developing reference materials.
The need for reliable, reproducible tests was reinforced by data from Mingfu Wang, research assistant professor at Rutgers University. His team found that the contents of many products purchased from local health food stores didn't match the label. What was claimed to be ginseng root was actually ginseng leaves, for example, and black cohosh was not from the species advertised.
In Washington D.C., the National Research Council and the Institute of Medicine have also weighed in on dietary supplements. At an April 1 briefing, they presented a framework for evaluating the safety of supplements for FDA and made recommendations to enhance FDA's ability to protect consumers from unreasonable risks associated with supplements.