The current Dietary Reference Intake recommendation is composed of:
- Estimated Average Requirements (EAR), expected to satisfy the needs of 50% of the people in that age group based on a review of the scientific literature.
- Recommended Dietary Allowances (RDA), the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board to meet the requirements of nearly all (97–98%) healthy individuals in each life-stage and gender group. It is calculated based on the EAR and is usually approximately 20% higher than the EAR (See "Calculating the RDA", below).
- Adequate Intake (AI), where no RDA has been established, but the amount established is somewhat less firmly believed to be adequate for everyone in the demographic group.
- Tolerable upper intake levels (UL), to caution against excessive intake of nutrients (like vitamin A) that can be harmful in large amounts. This is the highest level of daily consumption that current data have shown to cause no side effects in humans when used indefinitely without medical supervision.
The RDA is used to determine the Recommended Daily Value (RDV) which is printed on food labels in the U.S. and Canada.
Reference Daily Intake
Food and Nutrition Information Center / Dietary Guidance / Dietary Reference Intakes
Vitamin and Mineral Recommendations
Historical Comparison of RDIs, RDAs and DRIs, 1968 to Present for Vitamins:
1968 RDA -> RDI (highest RDA) + DRV (Daily Reference Values) = DV (Daily Values)
1974 RDA, 1980 RDA, 1989 RDA
1997 DRI (EAR -> RDA, AI, UL)
FDA Daily Value
Vitamin A: 1 IU = 0.3mcg, 1 mcg = 3.33 IU
Vitamin D: 1 IU = 0.025 mcg, 1 mcg = 40 IU
Vitamin E: 1 IU = 0.666 mg, 1 mg = 1.5 IU
