Food labeling is a highly visible application of the use of quantitative nutrient standards. As of 2000, food labels in both the U.S. and Canada still use values based on older standards (1983 Recommended Daily Nutrient Intakes in Canada and 1968 RDAs in the United States). In addition to providing consumers with information on the nutrient content of food products, the nutrient standards serve as a basis for nutrient content claims and health claims. For example, in the United States, if a food label contains a claim that the food is a good source of a vitamin, that food must contain at least 10 percent of the Daily Value (DV) for that vitamin in the serving portion usually consumed. The DV is based on the Reference Daily Intake, which was usually based on the highest RDA for adolescents or adults as established in the 1968 RDAs (NRC, 1968). To make a health claim with regard to lowering the risk of a chronic disease, a food must meet specific regulatory guidelines with respect to the required content of the nutrient for which the health claim is made. The food industry often uses messages on food labels to communicate and market the nutritional benefits of food products.
RDAs and RNIs have also been used as the basis for planning menus for groups of hospital patients, as a reference point for modifying diets of patients, and as a guide for the formulation of oral nutritional supplements or of complete enteral and parenteral feeding solutions. The use of quantitative nutrient standards for developing therapeutic diets and counseling patients requires caution since in the past, and now with the DRIs, these standards were established to meet the needs of almost all apparently healthy individuals. Those with therapeutic needs may not have their needs met, or they may have specific clinical conditions that would be worsened by consuming a nutrient at the recommended level. In developing therapeutic diets for patients with a specific disease, the usual procedure is first to use recommended intakes for nutrients that are not affected by the disease. For other nutrients, estimates are based on the best evidence of needs during illness. These assumptions are usually specified in the diet manuals of hospitals and professional associations.