RDA, AI, DV and UL: What Intake References Mean (and Do Not)
What RDA, AI, EAR, UL and the label Daily Value mean, how US, EU and UK reference values differ, and why a label percentage is not a personal dose.
Content last updated . This page has not been medically reviewed.
Why so many different numbers
Intake references are built for different jobs: planning diets for groups, setting safe ceilings, and printing a single number on a label. The same nutrient can therefore show several values. Always check which kind of value it is, which population it is for and which country's committee set it.United States: Dietary Reference Intakes (DRIs)
The DRIs are a family of reference values from the US National Academies; the 1998 B-vitamin report we read describes values for diets in Canada and the United States. They include the Estimated Average Requirement (EAR), the Recommended Dietary Allowance (RDA), the Adequate Intake (AI) and the Tolerable Upper Intake Level (UL). [1]| Term | Plain meaning |
|---|---|
| EAR | The intake estimated to meet the requirement of half of healthy people in a life stage and sex group. [1] |
| RDA | The average daily intake sufficient to meet the needs of nearly all (97 to 98 percent) healthy people in a life stage and sex group; intended as a goal for individuals. [1] |
| AI | Used instead of an RDA when evidence is not enough to calculate an EAR; based on observed or experimental intakes of healthy groups. [1] |
| UL | The highest daily intake likely to pose no risk of adverse effects in almost all individuals in that group; risk rises as intake goes above it. [1] |
Three points that are easy to miss:
- DRIs apply to the healthy general population. They do not cover people who are already malnourished or have conditions affecting absorption. [1]
- A UL may cover total intake or only intake from supplements and fortified foods, depending on the nutrient. For example, the 1998 report applied it to total intake for vitamin B6 and choline but to supplements and fortificants for niacin and folate. [1]
- If no UL exists, the report says this calls for caution above recommended intakes and does not mean high intakes are free of risk. [1]
United States: the label Daily Value (DV)
The Daily Value is not the RDA. On US labels, FDA describes DVs as the recommended amounts of nutrients to consume or not to exceed each day. The percent Daily Value (%DV) shows how much one serving contributes. For example, if the DV is 300 mcg and a serving has 30 mcg, that serving is 10% DV. FDA's general guide: 5% DV or less is low, 20% DV or more is high. [2]FDA's current list includes, for instance, vitamin C 90 mg and vitamin D 20 mcg. [2] The label DV is one reference number on a package; it is not tailored to your age, sex or health.
Europe and the UK
- EU (EFSA): Dietary Reference Values (DRVs) include the average requirement (AR), the population reference intake (PRI), the adequate intake (AI) and the tolerable upper intake level (UL). The PRI is calculated as the AR plus twice its standard deviation. EFSA stresses that DRVs are not nutrient goals or recommendations for individuals. [3]
- UK: The government's Dietary Recommendations (Public Health England, 2016) give figures for adults aged 19 and over, such as vitamin C 40 mg a day and vitamin D 10 micrograms a day. [4]
Same nutrient, different numbers
| Nutrient | US label DV | UK government recommendation (adults 19+) | Upper level in sources we read |
|---|---|---|---|
| Vitamin C | 90 mg [2] | 40 mg a day [4] | Not covered here |
| Vitamin D | 20 mcg [2] | 10 micrograms a day [4] | EFSA (EU): UL 100 micrograms a day for adults [3]; NHS (UK): do not take more than 100 micrograms (4,000 IU) a day [5] |
The gap does not mean one country is wrong. The values come from different committees, years, purposes and methods. Do not present one country's figure as universal.
Requirements versus supplement amounts
A reference intake is about total intake from food and supplements over time. A supplement can contain much more than one day's reference intake, and "%DV" can be very high. Amounts used in studies are different again: they are study amounts, not recommendations. We could not read the US NIH Office of Dietary Supplements pages (blocked from our systems), so this page does not list US RDA or UL values for individual nutrients. Check the nutrient pages in the Vitamins and Minerals sections.Practical use
- Check the serving size and the amount per serving, not only the %DV. See Reading supplement labels.
- Add up the same nutrient across products. See Amounts and duplicate ingredients.
- Ask a clinician or registered dietitian before going above a UL, especially in pregnancy, childhood or with medicines. See Supplement safety resources.
Frequently asked questions
Is the RDA the same as the Daily Value?
No. The RDA is a US National Academies reference for healthy people in a life stage and sex group. The DV is the single reference amount FDA uses for percentages on US labels. [1][2]
What does an Adequate Intake mean?
It is used when there is not enough evidence to calculate an average requirement, so it is set from observed intakes of healthy groups. [1]
Does "no UL" mean a nutrient is safe in any amount?
No. The National Academies explain that when a UL cannot be set, caution is still needed above recommended intakes. [1]
Are EU, UK and US values the same?
No. EFSA, UK government committees and the US National Academies and FDA publish separate values for separate purposes. [3][4][2]
References
- Institute of Medicine. Dietary Reference Intakes for Thiamin, Riboflavin, Niacin, Vitamin B6, Folate, Vitamin B12, Pantothenic Acid, Biotin, and Choline, Chapter 1: Introduction to Dietary Reference Intakes. National Academies Press, 1998. Read 2026-10-22.
- U.S. Food and Drug Administration. Daily Value on the Nutrition and Supplement Facts Labels. Page content current as of 03/05/2024. Read 2026-10-22.
- European Food Safety Authority. Dietary reference values. Read 2026-10-22.
- Public Health England. Government Dietary Recommendations: Government recommendations for energy and nutrients for males and females aged 1 to 18 years and 19+ years (August 2016). Read 2026-10-22.
- NHS (UK). Vitamin D. Read 2026-10-22.
Education, not medical advice. This page is for general information. It does not diagnose or treat any condition and is not a substitute for care from a qualified health professional. Natural does not automatically mean safe. Ask a clinician or pharmacist before changing your care, especially if you take medication, are pregnant or breastfeeding, or have a health condition.