cable to all nutrients because they assume normal distributions of daily intakes and requirements. A different methodology needs to be developed for nutrients for which the requirement distribution in the population is skewed (such as the iron requirements of menstruating women) or for which the distribution of daily intakes is skewed (as in the case of vitamin A, vitamin B₁₂, vitamin C, vitamin E, and perhaps several others). Until these new methods are available, individual assessment for these nutrients should continue to place emphasis on the types of information mentioned above for a qualitative assessment.

When an Estimated Average Requirement (EAR) for a nutrient is available, it is possible to make a quantitative assessment of the adequacy of the individual's usual intake of the nutrient. When an Adequate Intake (AI) is all that is available, it is still possible to determine whether the individual's usual intake is above the AI with a predetermined level of confidence. No conclusions can be drawn, however, when usual intake is below the AI. In this chapter, guidance is provided on how to determine whether an individual's usual intake of a nutrient exceeds the Tolerable Upper Intake Level (UL), suggesting that the usual intake is excessive. Note that use of the Recommended Dietary Allowance (RDA) is not recommended for individual assessment.

Whether one is interested in assessing the adequacy of the individual 's usual intake or in deciding whether usual intake exceeds the UL, the relevant information must include both the observed mean intake and the standard deviation (SD) of daily intakes for the individual. In the next section it is emphasized that usual intake is unobservable in practice, but for the purposes of assessment, it suffices to observe the individual 's daily intake over a few days and to have a reliable estimate of the SD of daily intake.

Is an individual's diet meeting nutrient needs? This question is fundamental to individual nutrition counseling and education. Answering this question is not an exact science, and the answer is considerably less precise than might be anticipated, especially because of the appearance of accuracy in computer printouts providing nutrient analysis of dietary intake data.

The Dietary Reference Intakes (DRIs) can be used to assess the