The National Academy of Sciences is a private agency that advises the federal government on scientific and technical matters. It is part of the National Academy, which also includes the National Academy of Engineering, the Institute of Medicine, and the National Research Council.
The NAS updates and publishes the Recommended Dietary Allowances (RDAs), which "represent the nutrient intake that is sufficient to meet the needs of nearly all healthy people in an age and gender group" (Wardlaw). More specific recommendations are needed for special populations, such as pregnant women, the elderly population, and those with medical conditions.
In addition, since all nutrients and food components do not have established RDAs, Dietary Reference Intakes (DRIs) were developed as a guide to adequate and safe standards for nutrients such as fiber, antioxidants, and trace elements, and for upper level intakes of vitamins and minerals.
Pauline A. Vickery
Wardlaw, Gordon M. (2000). Contemporary Nutrition: Issues and Insights, 4th edition. Boston: McGraw-Hill.
Whitney, E.; Catlado, C.; DeBruyne, L.; and Rolfe, S. (1996). Nutrition for Health and Health Care. Minneapolis, MN: West Publishing.
Williams, Sue R. (1993). Nutrition and Diet Therapy, 7th edition. St. Louis, MO: Mosby.