Balancing Safety of Dietary Supplements with the Free Market

• Dietary supplements
• Hepatitis, toxic
• Weight loss
• Product labeling
• Product surveillance
• postmarketing

A desire to take medications is, perhaps, the greatest feature which distinguishes man from other animals.

–Sir William Osler, 1891

In this issue, Favreau and colleagues report on cases of hepatotoxicity in users of the dietary supplement LipoKinetix (1). This dietary supplement was marketed as a weight-loss product and contained norephedrine (also known as phenylpropanolamine), caffeine, yohimbine, diiodothyronine, and sodium usniate. The authors report the experience of seven patients, each taking LipoKinetix for weight loss, who experienced severe liver injury within 12 weeks of ingesting this product.

This and other recent reports of adverse outcomes associated with use of supplements [2, 3] highlight two important issues that merit further consideration: 1) regulation and safety of dietary supplements and 2) safety surveillance.

The U.S. Congress has distinguished between what the U.S. Food and Drug Administration (FDA) considers to be a drug and a dietary or nutritional supplement. This regulatory distinction, however, is not based on biological data. Rather, it is a question of labeling. A product is considered to be a drug when it claims that it can treat, prevent, cure, mitigate, or diagnose a specific disease (4). In contrast, supplements can make only “structure/function” claims, such as “maintains a healthy circulatory system” (5).

To understand this distinction, one must consider the history of drug and supplement labeling. In 1937, 107 people in the United States died after exposure to elixir sulfanilamide as a result of the diethylene glycol solvent used in the elixir (6). In response to this event, Congress enacted the Food, Drug and Cosmetic Act of 1938, which required proof that a drug was safe before it could be marketed. Several decades later, the epidemic of birth defects associated with thalidomide use led to the 1962 Kefauver–Harris Amendment to the Food, Drug and Cosmetic …