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Dietary Reference Intake Components*

Estimated Average Requirement (EAR): Reflects the estimated median requirement and is particularly appropriate for applications related to planning and assessing intakes for groups of persons.

Recommended Dietary Allowance (RDA): Derived from the EAR and meets or exceeds the requirement for 97.5 percent of the population.

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

Adequate Intake (AI): Used when an EAR/RDA cannot be developed; average intake level based on observed or experimental intakes.


*Also, Acceptable Macronutrient Distribution Range (AMDR): An intake range for an energy source associated with reduced risk of chronic disease.

also supported a recent evaluation of the DRI development process, which has informed the approach used to develop this report. The evaluation pointed to the need for enhanced “transparency” about the decisions made, more clarification about uncertainties in the values, and use of a risk assessment framework to organize the scientific assessments. Risk assessment encompasses a series of decision steps and anticipates the need to address uncertainties through documentation and the use of expert judgment.


To set the stage for its review, the committee gathered background information on the metabolism and physiology of calcium and vitamin D (Chapters 2 and 3). It then identified those relationships that could potentially serve as indicators for establishing nutrient reference values for adequate intakes of the nutrients. To ensure comprehensiveness, the committee included relationships that appeared marginal by standard scientific principles as well as those suggested to be of interest by stakeholders. Box S-2 lists these potential indicators in alphabetical order. The close inter-relationship between calcium and vitamin D often resulted in potential indicators being relevant to both nutrients.

Chapter 4 provides the committee’s review of potential indicators,

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