sible to establish an EAR (and an RDA) for nutrients for which information is currently insufficient; and

• improve estimates of the distribution of requirements so that the appropriate method for assessing the prevalence of inadequacy for groups can be determined (cut-point method vs. probability approach).

For nutrients currently with an Adequate Intake (AI) (for age groups older than infants), research that allows replacement of the AIs with EARs will allow for additional applications. As discussed in earlier chapters, EARs present more possibilities for assessing individual and group prevalence of inadequacy. Whenever the data permit, EARs rather than AIs should be established.

Although there is need to improve the database of controlled experimental studies relevant to the EAR, there is even greater need to broaden the approach to estimating requirements. Congruence of evidence should be expected from different sources—including epidemiological and clinical investigations as well as experimental and factorial approaches —before being confident with an EAR. What is needed now is action in this direction and both financial and peer support for such approaches.

Establishment of Tolerable Upper Intake Levels (ULs) provides an opportunity to evaluate the risk of adverse effects for individuals and populations, and is an extremely important step forward in assessing intakes. Research should be undertaken to allow ULs to be set for all nutrients. In addition, information on the distribution of the UL (i.e., risk curves) would allow greatly expanded applications of the UL, particularly for population groups. More information is needed on ways to identify and conceptualize the risk of exceeding the UL.

Research on the factors that can alter requirements or upper limits is also needed to enable more accurate applications of the Dietary Reference Intakes (DRIs) to specific individuals and populations. Adjustment factors for considerations such as body size, physical activity, and intakes of energy and other nutrients may be appropriate but are often unknown.

Much has been written about ways to improve the quality of the intake data on which assessments are based; a number of these issues