To expeditiously and efficiently monitor the continually evolving and growing patterns of dietary supplement use, as well as their potential interactions with other consumed substances, FDA needs a cost-effective and scientifically sound approach to consider the safety of dietary supplement ingredients. For these reasons, FDA turned to the Institute of Medicine (IOM) of The National Academies to propose a framework for evaluating the safety of dietary supplement ingredients marketed in the United States. Specifically, FDA requested that an IOM committee (1) develop a proposed framework for categorizing and prioritizing dietary supplement ingredients based on safety issues, (2) describe a process for developing a system of scientific reviews with specifications for evaluating the safety of dietary supplement ingredients, and (3) develop at least six scientific reviews as prototypes for the system. The proposed framework is to include a methodology to review data with regard to the safety of dietary supplement ingredients, taking into consideration methods other expert bodies have used to categorize and review supplement safety and efficacy issues. FDA, in its request to IOM, asked that a framework for setting priorities and evaluating the safety of dietary supplement ingredients be proposed and released for comment, followed by the development of six prototype monograph reviews using the procedures outlined in the proposed framework. After development of the prototype monograph reviews, and based on comments received, the framework is to be revised based on the experience and concerns identified following its release.
The committee held four meetings while preparing the proposed framework. Three of these meetings included open sessions so the committee could hear from the sponsor and a number of individuals and organizations regarding aspects of evaluating the safety of dietary supplements. In addition, representatives of a number of agencies and organizations that currently evaluate chemical substances for various attributes were invited to discuss their methodologies and frameworks for approaching reviews of such substances. (See Appendix F for a list of those presenting at the open sessions of the committee.)
Many of the substances currently marketed as dietary supplements fall into the following categories: vitamins, minerals, herbs or other botanicals, amino acids, animal-derived products, hormones and hormone analogs, enzymes, and concentrates, metabolites, constituents, or extracts of these.2 Within each of these categories, products may be pure single entities of known or unknown chemical components, mixtures in which all or some components are known, or mixtures of unknown chemical components.
National surveys such as the Third National Health and Nutrition Examination Survey and the 1987 and 1992 National Health Interview Surveys indicate that 40 to 46 percent of Americans reported taking at least one vitamin or mineral supplement at some time within the month surveyed (Balluz et al., 2000; Slesinski et al., 1995). Several investigations have explored nutrient supplement (thought to be primarily vitamin and mineral formulations) use prevalence and trends in the United States (Balluz et al., 2000; Bender et al., 1992; Kim et al., 1993; Koplan et al., 1986; Slesinski et al., 1995; Subar and Block, 1990), as well as motivations for taking
While these are not dietary supplement categories specified by DSHEA, they illustrate the diversity of products currently marketed as dietary supplements. The 1994 DSHEA description of what constitutes dietary supplements can be found in Box 1-1.