Final answer:
The Recommended Dietary Allowance (RDA) is the nutrient intake level that is sufficient to meet the needs of nearly all healthy individuals in a certain group. It is based on the EAR, which is the estimated nutrient requirement for 50% of the population. The RDA is used to ensure that the dietary needs of 97-98% of healthy individuals are met.
Step-by-step explanation:
The Recommended Dietary Allowance (RDA) is the average daily nutrient intake level estimated to meet the requirement of nearly all (97-98%) healthy individuals in a particular group. It is the measure used by professionals to assess the quality of people's diets and provides an ample safety margin for each nutrient to ensure that the needs of virtually all healthy individuals in a specific age and gender group are met. The RDA is derived from the Estimated Average Requirement (EAR), which is the average requirement for 50% of the population. The EAR must be established before an RDA can be set, and this requires applicable research. The RDA aims to provide quantitative advice on nutrient amounts that are of benefit to individuals.
Other related standards include the Adequate Intake (AI), which is used when an RDA cannot be determined, and the Tolerable Upper Intake Level (UL) or simply "upper limit", which is the maximum daily intake unlikely to cause adverse health effects.