What are dietary reference intakes (DRI)?

Development

The dietary reference intakes (DRIs) include four reference values that can be used in assessing and planning a healthy diet throughout the life span: estimated average requirement (EAR), recommended dietary allowance (RDA), adequate intake (AI), and tolerable upper intake limit (UL). The RDA is the amount of a nutrient needed to meet the needs of nearly all healthy individuals. In setting the RDA, an EAR is first determined. The EAR is the amount of a specific nutrient that is believed to meet the needs of half of the population. Using the assumption of a normal distribution of nutrient needs, the RDA is calculated from the EAR and the standard deviation of requirements. When data are insufficient to calculate an EAR, the available data are used to estimate an AI. The AI is similar to the RDA but acknowledges that additional research concerning nutrient requirements is needed in that area. The UL represents the highest daily intake of a nutrient that is known to pose no health risks.

The EAR, RDA, and AI cannot be used to address the needs of those with chronic or acute disease. It can be assumed that intakes below the EAR probably need to be improved, since at this level 50 percent of the population would have inadequate intake. Intakes between the EAR for a specific nutrient and the RDA also may be improved. Intakes at or above the RDA probably are adequate, although many days of intake should be evaluated because of day-to-day variation. It is more difficult to be certain of the adequacy of intake when using AIs. However, in general, intakes below the AIs should probably be improved. Intakes at or above the UL should be lowered.

Nutrients for which EARs and RDAs have been established include phosphorus, magnesium, thiamine, riboflavin, niacin, vitamin B6, folate, vitamin B12, vitamin C, vitamin E, and selenium for adults and children over one year of age. Those for which an AI has been set include calcium, vitamin D, fluoride, pantothenic acid, biotin, and choline.

Perspective and Prospects

Although these reference values could be used for labeling and fortification guidelines, they are not yet being implemented as such. The current daily value (DV percent) on the nutrition facts labels rely on the 1968 version of the nutrient reference values. The major difficulty in applying the newer reference values for labeling purposes rests on how to choose a “reference” age group or gender. Currently the DV reflect needs for a male adult.

The first nutrient-based guidelines for healthy intake were released in 1941 in the United States, with similar guidelines released in Canada in 1938. Much research has occurred since that time concerning recording and assessing nutrient intake and in determining human requirements. However, the use of these guidelines has always been to assist in planning meals for individuals and groups, including federal assistance programs.

Bibliography

Insel, Paul M. Discovering Nutrition. 4th ed. Burlington, Mass.: Jones & Bartlett Learning, 2013.

Institute of Medicine, Food and Nutrition Board, Committee on the Use of Dietary Reference Intakes in Nutrition Labeling. Dietary Reference Intakes. Guiding Principles for Nutrition Labeling and Fortification. Washington, DC: National Academy Press, 2003.

Institute of Medicine, Food and Nutrition Board, Subcommittee on Interpretation and Uses of Dietary Reference Intakes and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes: Applications in Dietary Assessment. Washington, DC: National Academy Press, 2000.

Institute of Medicine, Food and Nutrition Board, Subcommittee on Interpretation and Uses of Dietary Reference Intakes and the Standing Committee on the Scientific Evaluation of Dietary Reference Intakes. Dietary Reference Intakes: Applications in Dietary Planning. Washington, DC: National Academy Press, 2003.

Ross, A. Catharine, et al., eds. Dietary Reference Intakes for Calcium and Vitamin D. Washington, DC: National Academies Press, 2011.

United States Department of Agriculture National Agricultural Library. "Dietary Reference Intakes." USDA, July 12, 2013.