In the United States, the Food and Drug Administration (FDA) regulates over-the-counter medications in addition to foodstuffs. However, herbal products and supplements are not directly regulated by the FDA, as the responsibility for ensuring the product's safety lies with the manufacturer. However, the FDA has on occasion stepped in to ban a certain herbal product, or to strongly warn against its use or marketing. Examples of such herbal products which the FDA either bans or cautions against are ephedrine, comfrey and aristolochic acid.
Ephedrine Alkaloids and Ma Huang
The Ma Huang plant contains the natural stimulants ephedrine and pseudoephedrine, which collectively are referred to as ephedrine alkaloids. Ephedrine is used in over-the-counter medications for the treatment of asthma, while pseudoephedrine is used as a nasal decongestant. In combination with other stimulants such as caffeine, ephedrine alkaloids can be dangerous. Dietary supplements containing ephedrine alkaloids and other stimulants have been marketed for dieters, athletes and those wishing to increase overall energy levels. Under a 2004 ruling by the FDA, the use of ephedrine alkaloids is banned for use in dietary supplements when other ingredients also have a known stimulant effect and the capability of interacting with ephedrine alkaloids. This ruling additionally prohibits such dietary supplements making labeling claims – for example, body building or weight loss potential – when long-term use of the supplement would be necessary to achieve these results.
Aristolochic Acid, Aristolochia plant
Although not outright banned by the FDA, several botanical dietary supplements have been the subject of strong FDA warnings against consumer use. These herbal products include aristolochic acid, a compound derived from the plant Aristolochia. Aristolochic acid is found in dietary supplements often marketed as traditional "herbal remedies" for weight loss. However, aristolochic acid has been identified as a possible cause of renal diseases including interstitial fibrosis and urothelial tract tumors. In 2001, the FDA issued a warning against use of products containing aristolochic acid.
Comon Comfrey, Prickly Comfrey, Russian Comfrey
Comfrey is a herbal ingredient occurring in several varieties – common comfrey, prickly comfrey and Russian comfrey. Comfrey is purported to have a positive effect on bone healing, and is sold in dietary supplements for a variety of uses. The pyrrolizidine alkaloids present in comfrey are considered by the FDA to present a serious health hazard when taken orally. Pyrrolizidine alkaloids have been proven to be toxic to the liver, and are also considered toxic to other body tissues. Additionally, there is some evidence that these alkaloids are carcinogenic. In July 2001, the FDA advised the manufacturers of dietary supplements to remove products containing comfrey from the market. Today, products containing comfrey are typically labeled "for external use only."
Summary
In the United States, sale of herbal products as dietary supplements is relatively unregulated. If you are in any doubt about the safety of a supplement which is available without a prescription, it is safest not to take the supplement. Consult your doctor for medical advice before taking any new supplements.
Sources:
FDA.gov, *"Dietary Supplement Alerts" (accessed March 19, 2011)
FDA.gov: *"Federal Register Final Rule - FR69 6787 Final Rule Declaring Dietary Supplements Containing Ephedrine Alkaloids Adulterated Because They Present an Unreasonable Risk" (accessed March 19, 2011)
FDA.gov: *"Letter to Health Professionals Regarding Safety Concerns Related to the Use of Botanical Products Containing Aristolochic Acid" (accessed March 19, 2011)
FDA.govn: *"FDA Advises Dietary Supplement Manufacturers to Remove Comfrey Products From the Market" (accessed March 19, 2011)
Herbs.org: *"Herb Information Greenpaper" (accessed March 19, 2011)
