Dietary allowances: what to recommend

Within recent years Recommended Dietary Allowances (RDAs) have come to play a major role in a wide range of governmental, health and industrial affairs. Each of these applications, however, sets different specific requirements. All too frequently the basic RDA values end up by becoming processed in ways which exceed the limits of the science on which the recommendations were formulated. Currently, the same sets of RDAs are being applied to functions as varied as food labelling, public health assessments of populations, agricultural planning, the organisation of diets for institutional feeding and the diagnosis of under-nutrition or malnutrition. In order that these actions can be carried out effectively and meaningfully, a knowledge of how RDAs are derived and expressed is essential.