Cover Image


View/Hide Left Panel
  • A Recommended Dietary Allowance (RDA) for folate that is the same for men and women; however, for women who are capable of becoming pregnant, a special recommendation is made for intake of folate from fortified food or supplements.

  • For adults over age 50, the use of food fortified with vitamin B12, or B12 supplements to meet most of the RDA for B12.

  • Recommendations for choline intake (recommendations for all the B vitamins had been made previously).

  • Suggested maximum intakes of niacin, vitamin B6, folate from supplements and fortified foods, and choline.

  • A research agenda that focuses primarily on folate and vitamin B12.


Dietary Reference Intakes (DRIs) are reference values that are quantitative estimates of nutrient intakes to be used for planning and assessing diets for healthy people. They include RDAs but also three other types of reference values (see Box S-1). Although the reference values are based on data, the data were often scanty or drawn from studies that had limitations in addressing the question. Thus, scientific judgment was required in setting the reference values.

BOX S-1 Dietary Reference Intakes

Recommended Dietary Allowance (RDA): the average daily dietary intake level that is sufficient to meet the nutrient requirement of nearly all (97 to 98 percent) healthy individuals in a particular life stage and gender group.

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

Tolerable Upper Intake Level (UL): 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.

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

The National Academies of Sciences, Engineering, and Medicine
500 Fifth St. N.W. | Washington, D.C. 20001

Copyright © National Academy of Sciences. All rights reserved.
Terms of Use and Privacy Statement