Three decades of dietary recommendations.

The scope of Recommended Dietary Allowances (RDAs) has markedly expanded since their first edition in 1941. There were changes from simple goals to complex, health-related objectives and a nearly threefold increase of nutrients with recommended intakes. These changes reflect the development of scientific knowledge as well as increasing public awareness of the relation of nutrition to health. This review discusses the development of the RDAs, especially during the past 30 years, and examines the changes of definitions, goals, and paradigms.