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How RDAs and DRIs Are Set

This content is for informational purposes only and does not constitute medical advice. Statements about dietary supplements have not been evaluated by the FDA and are not intended to diagnose, treat, cure, or prevent any disease. Individual results may vary — consult your healthcare provider before starting any supplement. Full disclaimer

Dietary Reference Intakes (DRIs) are the science-based reference values for nutrients, set by the National Academies.

Dietary Reference Intakes (DRIs) are the science-based reference values for nutrients, set by the National Academies. They include the EAR (meets 50% of people's needs), the RDA (meets 97–98%), the AI (used when data are limited), and the UL (the safe ceiling). They vary by age and sex.

Key Takeaways

  • RDA, AI, EAR, and UL are all part of the Dietary Reference Intakes (DRIs), set by the National Academies.
  • EAR meets 50% of a group's needs; RDA is derived from it to meet 97–98%.
  • AI is used when evidence is too limited to set an RDA; UL is the safe upper ceiling.
  • Values vary by age, sex, pregnancy, and lactation because needs differ across life stages.
  • The % Daily Value on labels is derived from these reference values.

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The DRI family

When a label or fact sheet cites an 'RDA' or 'UL,' those come from the Dietary Reference Intakes (DRIs) — a set of reference values developed by the Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine [1]. There are four main types:

  • Estimated Average Requirement (EAR): the average daily intake estimated to meet the needs of 50% of healthy people in a group [1]. It's the starting point scientists use.
  • Recommended Dietary Allowance (RDA): the intake sufficient to meet the needs of nearly all (97–98%) healthy people [1]. It's derived statistically from the EAR, which is why an RDA only exists when there's enough data to set an EAR.
  • Adequate Intake (AI): used when evidence is insufficient to set an EAR/RDA; it's an intake assumed to ensure adequacy, often based on what healthy people typically consume [1].
  • Tolerable Upper Intake Level (UL): the maximum daily intake unlikely to cause harm [1] (see [upper intake levels](/learn/upper-intake-levels-explained)).

How they're determined

Expert committees review the available human evidence for each nutrient and life stage, identify a requirement where possible, and build in a margin so the RDA covers nearly everyone. Values vary by age and sex (and for pregnancy and lactation), because needs differ across the lifespan [1].

How this reaches your label

The % Daily Value on supplement and food labels is derived from these reference values [2], giving a single consumer-friendly figure (see percent Daily Value and RDA, AI, and UL).

Why it matters

Understanding the DRI framework helps you read claims sensibly: an RDA is a population target (most people need less than it), an AI is a best estimate when data are thin, and a UL is the ceiling to stay under. None of them is a personalized prescription — individual needs vary, which is where a clinician or dietitian comes in.

Frequently Asked Questions

What's the difference between the RDA and the EAR?

The EAR is the intake that meets the needs of about half of a healthy group and is the scientific starting point. The RDA is built from the EAR with a margin added so it covers nearly all (97–98%) of healthy people, which is why an RDA only exists when there's enough data to set an EAR.

When is an Adequate Intake (AI) used instead of an RDA?

When the evidence isn't strong enough to establish an EAR and RDA. An AI is an intake assumed to ensure adequacy, often based on what healthy people typically consume. Several nutrients, like pantothenic acid and biotin, have an AI rather than an RDA.

Who decides these values?

The Food and Nutrition Board of the National Academies of Sciences, Engineering, and Medicine. Expert committees review the human evidence for each nutrient and life stage and set the reference values, which are periodically updated as new evidence emerges.

Does the RDA mean exactly how much I personally need?

Not exactly. The RDA is a population target set to cover nearly everyone, so most individuals actually need somewhat less. It's a useful planning figure, but personal needs vary with health, life stage, and other factors, which is where individualized advice helps.

References

  1. National Institutes of Health, Office of Dietary Supplements (2024). Nutrient Recommendations: Dietary Reference Intakes (DRIs). NIH Office of Dietary Supplements.
  2. National Institutes of Health, Office of Dietary Supplements (2023). Dietary Supplements: What You Need to Know. NIH Office of Dietary Supplements.