ore than half of us adults use dietary supplements, and nutrient-containing supplements are by far the most popular. Depending on their nature and dose,
the ingredients in supplements have positive, negative, or no health effects. Therefore, health professionals must be able to provide counsel about dietary supplement use, knowing that individual products may vary in their strength and chemical composition and therefore in their bioactive properties. These properties, along with the integrity of the manufacturing processes used (eg, purity and proper ingredient identification), will determine safety and efficacy. Supplements differ from foods and drugs in important ways that may affect the metab- olism of the nutrients and bioactives they contain, and they are also regulated differently than foods. The dissemination of objective and reliable sources of information on dietary supplement science is critical to make evidence-based clinical practice a reality. We applaud the editor and contributors for producing this resource, which furthers those efforts. The Health Professional’s Guide to Dietary Supplements provides a desktop reference with much of this information in a single ready-to-use format.
Johanna T. Dwyer, DSc, RD Senior Nutrition Scientist (Contractor) Office of Dietary Supplements, National Institutes of Health
Joseph M. Betz, PhD Former Acting Director Office of Dietary Supplements, National Institutes of Health