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Dietary Reference Intakes (DRIs)

RDA (Recommended Dietary Allowance): the intake level that is sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a group.

AI (Adequate Intake): a value based on observed or experimentally determined approximations of nutrient intake by a group (or groups) of healthy people—used when an RDA cannot be determined.

UL (Tolerable Upper Intake Level): the highest level of daily nutrient intake that is likely to pose no risk of adverse health effects to almost all individuals in the general population. As intake increases above the UL, the risk of adverse effects increases.

EAR (Estimated Average Requirement): a nutrient intake value that is estimated to meet the requirement of half the healthy individuals in a group.

NOTE: DRIs are expressed as intakes per day but they are meant to represent intakes averaged over time.


Nutrient Recommendations for Individuals

The Recommended Dietary Allowance (RDA) is the value to be used in guiding healthy individuals to achieve adequate nutrient intake. It is a goal for average intake over time; day-to-day variation is to be expected. RDAs are set separately for specified life stage groups and sometimes they differ for males and females. The RDAs are not intended to be used for planning diets for groups or assessing the nutrient intakes of free-living groups (Beaton, 1994). Rather, the RDAs are intended to ensure the adequacy of nutrient intake. If a healthy person meets the RDA for a nutrient, there is only a very slight chance that the intake is inadequate for this person.

The RDA is expressed as a single absolute value. For example, from Chapter 6, the RDA and thus the recommended daily intake of niacin for women ages 19 through 30 years is 16 mg/day of niacin equivalents. This would be the case for a woman in this age

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