and their long-term intake may be less than that which apparently decreases risk of the disease state.
If the strength of the data that associate risk of disease with the nutrient in question is sufficient to permit AIs to be based on such data, and national survey intake data indicate that the median intake is below the AI, then methods must be determined for individuals to increase consumption in order to decrease risk due to inadequate dietary intakes. Primary methods to accomplish this include educating consumers to change their food consumption behavior, increasing intake of fortified foodstuffs, providing dietary supplements, or a combination of these methods. It is not the function of this report, given the scope of work outlined, to analyze the potential impact of using these methods.
The benefits of food as the source of nutrients are well described in previous FNB reports (NRC, 1989a, 1989b). Obtaining RDAs and AIs from unfortified food continues to have the advantage of (1) providing intakes of other beneficial nutrients and food components, for which RDAs and AIs may not be determined, and (2) potentially enhancing intakes through interactions with other nutrients simultaneously. It is recognized, however, that the low energy intakes reported in recent national surveys and thought to result from decreased physical activity may mean that it would be unusual to see changes in food habits to the extent necessary to maintain intakes by all individuals at levels recommended in this report. Eating fortified food products represents one method by which to increase or maintain intakes without major changes in food habits. For some individuals at higher risk, nutrient supplements may be desirable in order to meet reference intakes.
It is not the function of this report, given the scope of the work (see Appendix A, Origin and Framework of the Development of Dietary Reference Intakes), to address applications of the DRIs, including assessment of the adequacy of intakes of various population groups and planning for intakes of populations or for groups with special needs. However, some uses for the different types of DRIs are described briefly in Chapter 9. A subsequent report will focus on uses of DRIs in various settings.
Expert groups in many countries have developed reference values for nutrient intakes (Table 1-1). The number of life stage groups identified by these countries varies considerably. For example, the number of age categories identified within the first year of life rang-