FIGURE 4-2 Dietary reference intakes. This figure shows that the Estimated Average Requirement (EAR) is the intake at which the risk of inadequacy is estimated to be 0.5 (50 percent) to an individual. The Recommended Dietary Allowance (RDA) is the intake at which the risk of inadequacy would be very small—only 0.02 to 0.03 (2 to 3 percent). At intakes between the RDA and the Tolerable Upper Intake Level (UL), the risks of inadequacy and of excess are both estimated to be close to 0. At intakes above the UL, the potential risk of adverse effects may increase. SOURCE: IOM (2002a).

given in each DRI report to the choice and justification of the criterion used to establish requirement values and the intake levels beyond which the potential for increased risk of adverse effects may occur.


Estimated Average Requirement

The Estimated Average Requirement2 (EAR) is the daily intake value that is estimated to meet the requirement, as defined by the specified indicator or criterion of adequacy, in half of the apparently healthy individuals in a life stage or gender group (see Figure 4-2).


The definition of the EAR implies a median as opposed to a mean, or average. The median and average would be the same if the distribution of requirements followed a symmetrical distribution and would diverge as a distribution became skewed.

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