Alternative Medicine
Herbal Products and Dietary Supplements
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The term dietary supplement refers to any product containing a vitamin, mineral, herb, amino acid, or other substance used to supplement the diet which is taken orally and is labeled as a dietary supplement. They are different from drugs in that they cannot be marketed to prevent, treat, or diagnose any disease and are available without a prescription. Another big difference is that their safety and efficacy (effectiveness) do not have to be proven before they are marketed. This lack of regulation presents a major concern today, and serious problems have arisen with regard to purity, potency, safety, and potential drug interactions with various dietary supplement products. Unfortunately, a product has to be proven to be unsafe or hazardous before it can be banned by the Food and Drug Administration (FDA).
With regard to purity and potency, there have been numerous studies published in the medical literature reporting that many dietary supplements do not contain what the label says they contain. Some products actually contain none of the active product they are supposed to, while others contain up to ten times the labeled amount of active ingredient. Contaminants such as bacteria, prescription medications (Warfarin, steroids, benzodiazepines), pesticides, and heavy metals such as lead, mercury, and arsenic, have also been identified in a number of cases. With the current lack of manufacturing regulations, one can never be sure about what is in the bottle when a dietary supplement is purchased.
Evidence has been rapidly mounting that many dietary supplement products are unsafe. The FDA has recently issued public health warnings about products including kava, aristolochic acid, and comfrey due to reports of kidney failure, liver toxicity, and cancer attributed to these herbs. Ephedra products have been linked to strokes, seizures, psychosis, heart attack, and death. Other substances reported to cause seizures include melatonin, yohimbine, evening primrose oil, and skullcap. It is estimated that less than 1 percent of adverse events due to dietary supplements are reported to the FDA, and because there are no requirements for safety to be established prior to marketing, any dietary supplement should be regarded as potentially hazardous.
Much recent attention has focused on identifying drug interactions with dietary supplements. St. John's Wort has been one of the most extensively studied, and has been found to decrease the levels of a number of prescription medications and make them ineffective. Due to the mechanism for this interaction, it has the potential to interact with hundreds of prescription medications used to treat heart disease, hypertension, epilepsy, cancer, HIV infection, blood clotting disorders, and others. Other dietary supplements suspected of causing a similar interaction include DHEA, goldenseal, echinacea, ginkgo, chamomile, and cat's claw. The majority of dietary supplements have never been studied to determine their drug interaction potential, so anyone taking prescription medications should avoid these products.
In summary, dietary supplements pose a major public health concern. The need for new regulations governing these products has been recognized by the medical community and will probably be established in the near future. Until their safety and efficacy can be assured, dietary supplements are not recommended for use.
Sara Grimsley Augustin, Pharm.D. and Board-Certified Psychiatric Pharmacist (BCPP), is on faculty at Mercer University Southern School of Pharmacy in Atlanta , GA , where she teaches in the areas of psychiatry, neurology, and substance abuse. Dr. Augustin has provided consultant pharmacy services to Restore Neurobehavioral Program since 1992 and has worked with this program to optimize outcomes in neurobehavioral pharmacotherapy.