The AI cannot be used to calculate the prevalence of inadequate nutrient intakes for groups. However, for nutrients with appropriately estimated AIs (see Table 5-1), groups with mean intakes at or above the AI can generally be assumed to have a low prevalence of inadequate intakes (low group risk) for the defined criterion of nutritional status. When mean intakes of groups are below the AI, assumptions cannot be made about inadequacy of intakes (except when intakes are zero, in which case intake is clearly inadequate). Thus, the following statements can be made:
If the mean intake of a group is at or above the AI, and the variance of intake is similar to the variance of intake in the population originally used to set the AI, the prevalence of inadequate nutrient intakes is likely to be low (although it cannot be estimated) (see Table 5-1 and Appendix F). This evaluation can be used with confidence when the AI is based directly on intakes of healthy populations (as is the case for all AIs except for vitamin D for infants 0 through 12 months of age, for pantothenic acid, and fluoride for children and adults). However, one would have less confidence making this type of evaluation when the AI is not based directly on the intakes of healthy populations.
If the mean intake is below the AI, the adequacy of the group's intake cannot be determined.
Can the proportion of the population below the AI be used as an indicator of the percentage of the population whose intakes are inadequate?
Because the AI should be above the true Estimated Average Requirement (EAR), any prevalence estimates of nutrient inadequacy calculated by counting individuals with intakes below the AI would be overestimates —potentially major overestimates—of the true prevalence. Thus, although the EAR may be used as a cut-point, the AI may not be used as a cut-point to estimate the percentage of a population with inadequate intakes.