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many of the specific uses and applications of dietary reference standards fall into the two general categories defined implicitly in 1941—diet planning and diet assessment. Diet planning applications involve using dietary reference standards to develop recommendations for what intakes should be (i.e., as a goal for good nutrition). Diet assessment applications involve determining the probable adequacy or inadequacy of observed intakes (i.e., a yardstick by which to measure progress). These two general applications of dietary reference standards are interrelated.

The first Canadian dietary standards—DRNIs—were issued by the Canadian Council on Nutrition (1938) and stated that the standards were to be used as the basis for evaluation of observed diets. It was not clear whether group diets (group mean intakes) or individual diets were intended.

The 1990 version of the RNIs and 1989 RDAs did not differ in the described derivations of the recommended intakes but differences remain about how intended uses are described, resulting in some confusion for the users of both reports. The joint U.S. and Canadian development of the new Dietary Reference Intakes (DRIs) should resolve this confusion.

Conceptual Framework

Figure 2-1 illustrates a conceptual framework adapted from one first developed by Beaton (1994) which can be applied to the uses of dietary reference standards. As shown in this figure, knowledge about distributions of requirements and intakes feeds into the two general applications of diet planning and assessment. Within each of these general categories, the applications differ according to whether they are for an individual or for population groups.

The simplicity of this conceptual framework belies the complexity in using and interpreting DRIs to plan and assess diets. In the past, both planning and assessment applications relied primarily on the former RDAs or RNIs because these were the only quantitative nutrient reference standards widely available. The concepts underlying the former RDAs often were not well understood and thus some applications of the former RDAs for both assessment and planning were not appropriate (IOM, 1994). For the three newly introduced dietary reference intakes —the Estimated Average Requirement (EAR), Adequate Intake (AI), and Tolerable Upper Intake Level (UL)—guidance is needed to differentiate which should be used in various applications in diet assessment and planning. As discussed in the next section, the wide range of uses for dietary

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