Dietary supplements and functional foods: 2 sides of a coin?

Dietary supplements are used by more than one-half of the adult US population. In contrast to pharmaceuticals, dietary supplements may be sold in the United States with little regulation other than listing of ingredients and the potential health benefits. By contrast, herbal products in Germany are carefully regulated by the same standards as drugs, and efforts are under way to standardize their regulation in the entire European Union. Most herbal users do not inform their physicians that they are taking these supplements, and most physicians do not inquire. Although some herbal products have clinically proven benefits, it is increasingly apparent that many contain potentially toxic substances, particularly in relation to interactions with drugs. Hence, it is essential that practicing physicians develop a working knowledge of herbals-specifically, about claims for their usage and potential or proven efficacies and toxicities-and that they incorporate such knowledge into the evaluation and management of their patients. By contrast, functional foods-integral components of the diet that are understood to contribute added health benefits-are the subject of intense and widespread research in food and nutritional science. Examples include many polyphenolic substances, carotenoids, soy isoflavones, fish oils, and components of nuts that possess antioxidant and other properties that decrease the risk of vascular diseases and cancer. Practicing physicians are advised to stay abreast of these emerging findings in order to best advise their patients on the value of health-promoting diets in disease prevention.