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Can the relative adequacy of two groups—or of one group at two different times—be assessed by comparing mean intakes with the AI or by comparing the proportion of the groups below the AI?


Because the AI may be above the (unknown) Recommended Dietary Allowance (RDA), mean intakes well below the AI may still have a low prevalence of nutrient inadequacy. It is not possible to know exactly where the mean intake as a percentage of the AI becomes associated with an increased risk of inadequacy. For example, mean intakes at 70 and 90 percent of the AI may have virtually identical very low risks of inadequacy. Therefore, comparisons of this type should be avoided.

Can we calculate back from the AI to a proxy for a nonexistent EAR?


Another potential misuse of the AI is calculating back under the assumption that a proxy for the EAR can be determined. Because the AI is used as a target in counseling individuals—just as the RDA is used as an intake target—there is a strong possibility that the AI will be misused in much the same way as the former RDAs were misused. Some may assume that it is appropriate to use an actual standard deviation of intake or assume a certain coefficient of variation of requirements to calculate back from the AI to a value that might be assumed to be close to the EAR.

Two times the assumed coefficient of variance of requirements (approximately 10 percent) might be subtracted from the AI with the assumption that the resulting number would be a proxy for the requirement. In fact this would only be the case if the AI were set so that only 2 to 3 percent of the population was below the EAR and the requirement was normally distributed (Beaton, 1994). Conceptually this may be the case, but in actuality the AI is derived from a different perspective. In fact, the AI involves significantly more assumptions and judgment, and is set differently for each nutrient. For all of these reasons it is not appropriate to calculate a pseudo EAR from the AI. Such attempts will result in estimates of the prev-

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