<P> The Dietary Reference Intake (DRI) is a system of nutrition recommendations from the Institute of Medicine (IOM) of the National Academies (United States). It was introduced in 1997 in order to broaden the existing guidelines known as Recommended Dietary Allowances (RDAs, see below). The DRI values differ from those used in nutrition labeling on food and dietary supplement products in the U.S. and Canada, which uses Reference Daily Intakes (RDIs) and Daily Values (% DV) which were based on outdated RDAs from 1968 but were updated as of 2016 . </P> <P> DRI provides several different types of reference values: </P> <Ul> <Li> 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 . </Li> <Li> Recommended Dietary Allowances (RDA), the daily dietary intake level of a nutrient considered sufficient by the Food and Nutrition Board of the Institute of Medicine to meet the requirements of 97.5% of healthy individuals in each life - stage and sex group . The definition implies that the intake level would cause a harmful nutrient deficiency in just 2.5% . It is calculated based on the EAR and is usually approximately 20% higher than the EAR (See Calculating the RDA). </Li> <Li> 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 . </Li> <Li> 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 nutrient consumption that is considered to be safe for, and cause no side effects in, 97.5% of healthy individuals in each life - stage and sex group . The definition implies that the intake level would cause a harmful nutrient excess in just 2.5% . The European Food Safety Authority (EFSA) has also established ULs which do not always agree with U.S. ULs . For example, adult zinc UL is 40 mg in U.S. and 25 mg in EFSA . </Li> <Li> Acceptable Macronutrient Distribution Ranges (AMDR), a range of intake specified as a percentage of total energy intake . Used for sources of energy, such as fats and carbohydrates . </Li> </Ul> <Li> 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 . </Li>

Vitamin d has an ai but not an rda. this means that