An editorial by an Oregon Health & Science University Casey Eye Institute researcher in the American Journal of Ophthalmology suggests herbal and nutritional supplements should be studied and regulated the same way as prescription medications. Currently no official standards exist governing their production, and the potency and purity of these products vary widely.
Studies suggest more than 50 percent of the U.S. population take dietary supplements, yet only half tell their physician they do so. Not only can many of these supplements cause potentially harmful reactions, they can also interact adversely with prescription medications.
"Very few controlled, clinical trials have studied herbal or dietary supplements, so the observed effects are subjective and clinicians lack information on dosing, efficacy, safety and drug interactions," said Frederick W. Fraunfelder, M.D., assistant professor of ophthalmology in the OHSU School of Medicine and the OHSU Casey Eye Institute.
Unlike prescription and over-the-counter medications, herbal and nutritional supplements are not regulated by the Food and Drug Administration (FDA). Marketers of supplements are barred from making specific claims about treatment, prevention, diagnosis or cure of specific diseases, but many still make misleading claims. The FDA can remove potentially dangerous supplements from the market, but it is a costly and onerous process.
Because of a lack of standardized manufacturing and quality-control processes, the purity of some nutritional supplements is questionable. One study found only 50 percent of products labeled as containing ginseng actually did so.
Many herbal and nutritional supplements show promise in treating a variety of ailments. Flax seed oil, primrose oil and fish oil may be beneficial for the treatment of dry eye syndrome. Antioxidant vitamins have proven effective for treating macular degeneration. Given the public's desire to use natural products and the potential for therapeutic benefits, Fraunfelder suggests these products be studied in the same manner as prescription drugs so that data on efficacy, proper dosage and drug interactions would be more readily available.
"Steering the dietary supplement industry toward proving safety and efficacy will protect patients and the added knowledge will benefit clinicians and the public," said Fraunfelder, who is also director of the National Registry of Drug-Induced Ocular Side Effects based at the OHSU Casey Eye Institute.