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Dietary Reference Intakes for Vitamin A, Vitamin K, Arsenic, Boron, Chromium, Copper, Iodine, Iron, Manganese, Molybdenum, Nickel, Silicon, Vanadium, and Zinc
intakes above the UL; some interventions may increase the intake of only those most at risk (usually by individual intervention), while others may increase the intake of the entire group (such as fortification of the food supply); and
the selection of the degree of risk that can be tolerated when planning for the group (for example, a 2 to 3 percent prevalence versus a higher or lower prevalence).
Using the Adequate Intake for Groups
Adequate Intakes (AIs) have been established as mean or median intakes of healthy groups for some nutrients discussed in this report. This includes all nutrients for infants fed human milk through 6 months of age and the nutrients vitamin K and manganese for adults. Planning a group intake that meets the AI should, by definition, be associated with a low prevalence of inadequacy. This, of course, assumes that the group being planned for has similar characteristics to the group used to establish the AI. For chromium, the only nutrient in this report with an AI that is not based on the mean or median intake of healthy groups, there is less certainty that group mean intakes equal to or above the AI will be associated with a low prevalence of inadequacy.
A major change in the extent to which provitamin A carotenoids can be used to form vitamin A is the replacement of retinol equivalents (μg RE) with retinol activity equivalents (μg RAE) for the provitamin A carotenoids. The RAEs for dietary β-carotene, α-carotene, and β-cryptoxanthin are 12, 24, and 24 μg, respectively, compared to corresponding REs of 6, 12, and 12 μg reported by the National Research Council (NRC, 1989). It is recommended that future food composition and intake tables use actual weights (μg) of provitamin A carotenoids rather than use converted data based on the equivalency to vitamin A. This prevents confusion as to whether the RE or RAE has been used for determining the total vitamin A content of a food or for estimating total vitamin A intakes. This change raises two issues: (1) how vitamin A intakes can be determined using the currently available U.S. Department of Agriculture’s (USDA) Nutrient Database for Standard Reference, and (2) how to interpret published data on vitamin A intakes of various population groups.