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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
which include reported intakes from supplements, illustrate that the proportion of U.S. women aged 51 to 70 years who exceed this UL is just over 1 percent. In contrast, when data from food alone are examined, the proportion of the population with intakes above the UL is less than 1 percent (Appendix Table C-25).
In typical North American food-based diets, ULs for vitamin A, iodine, iron, manganese, molybdenum, and zinc can rarely be exceeded. The UL for copper pertains to food sources and copper supplements. Use of dietary supplements containing these nutrients would be the primary reason for exceeding the ULs.
The mean intake of a population cannot be used to evaluate the prevalence of intakes above the UL. A distribution of usual intakes, including intakes from supplements and drinking water, is required to assess the proportion of the population that might be at risk of overconsumption.
PLANNING NUTRIENT INTAKES OF INDIVIDUALS
Using the Recommended Dietary Allowance for Individuals
Individuals should use the Recommended Dietary Allowance (RDA) as the target for their daily nutrient intakes if an RDA has been established. For example, to increase their vitamin A consumption to meet the RDA (900 and 700 μg/day for men and women, respectively), adults can increase their intake of foods that provide preformed vitamin A (including dairy products, eggs, margarine, liver) and carotenoids like β-carotene (deep green and yellow fruits and vegetables). An 8-ounce glass of milk contains about 65 μg of preformed vitamin A, and a half-cup serving of carrots contains the equivalent of approximately 950 μg of vitamin A as β-carotene.
Using the Adequate Intake for Individuals
Adequate Intakes (AIs) are set for infants through 6 months of age for all nutrients, and for all nutrients except iron and zinc, for infants 7 through 12 months of age. Human milk will supply the AI for a nutrient for term infants through 6 months of age, and so it is not necessary to plan additional sources of intakes for infants exclusively fed human milk. Likewise, an infant formula with a nutrient profile similar to human milk (after adjustment for differences in bioavailability) should supply adequate nutrients for an infant.
In this report, AIs are also set for children, adolescents, and adults