Under the Dietary Supplement Health and Education Act (DSHEA) of 1994, a dietary supplement includes vitamins, herbs or other botanicals, amino acids, dietary substances such as enzymes, and food extracts, such as the isoflavones in soybeans. Unlike prescription and over-the-counter medications, which must undergo rigorous scientific study before receiving Food and Drug Administration (FDA) approval, under DSHEA, the manufacturer is solely responsible for the safety of their product and the claims they make when marketing it. While the FDA requires manufacturers list ingredients on the product label, the quality of those ingredients does not have to be evaluated, nor does the amount of a given ingredient have to be listed. Even if the amount is listed, the products are not tested to ensure that amounts given on the label are accurate.
"The important thing is that herbal medications, which are in the category of the dietary supplements, are not as vigorously regulated by the FDA as prescription drugs," explains Chun-Su Yuan, MD, a professor in the department of anesthesia and critical care and the director of the Tang Center for Herbal Medicine Research at the University of Chicago. "So the FDA does not regulate them until the adverse effects actually happen. At that point, the FDA would step in, such as when ephedra-containing dietary supplements were banned at the end of last year."
Because of a report that ginseng had interacted with warfarin in a patient, Dr. Yuan and his colleagues conducted a study published in the July 6th issue of The Annals of Internal Medicine, examining whether the popular herbal supplement ginseng changes the effectiveness of warfarin, a drug given to people with certain cardiovascular conditions to prevent blot clots. The researchers evaluated American ginseng, which is a type of ginseng commonly taken for fatigue, immune function and general health. While ginseng may promote bleeding in surgical patients, it reduced the anti-clotting effect of warfarin in this study.
