What Is an Adequate Intake (AI)?
Definition
Adequate Intake (AI): The reference value used for a nutrient when an average requirement cannot be set: the average daily intake observed in a group of healthy people and assumed to be adequate (EFSA).
An adequate intake (AI) is the reference value given for a nutrient when an average requirement cannot be set. The European Food Safety Authority (EFSA) defines it as the average daily intake observed in a group of healthy people that is assumed to be adequate. EFSA gives daily water needs this way. This is general information, not medical advice.
Where it appears in the formulas
water to drink = EFSA adequate intake × 80%. For an adult woman the adequate intake is 2 L, so the part to drink is 2 × 80% = 1.6 L; for a man 2.5 L gives 2 L. In pregnancy EFSA adds 0.3 L, in proportion to the increase in energy intake, and about 0.7 L when breastfeeding.
How it differs from an average requirement
Where EFSA can measure the average requirement (AR) of a group, it sets a value that covers almost everyone (PRI). For nutrients such as water, whose need varies widely by person and conditions, that value cannot be set; an adequate intake based on observed intakes is given instead. So an AI is not a strict minimum but a level assumed to be adequate.