RDA stands for recommended daily allowance or recommended dietary allowance. It is part of the system of nutritional recommendations and nutrient consumption. In the United States, RDA is sometimes used interchangeably with RDI (recommended dietary intake).
The RDA is defined as the average daily dietary level of nutrient intake that sufficiently meets the requirements of nearly all (about 97 per cent to 98 per cent) of the healthy population. The RDA values are used to create the recommended daily values (RDV) for nutrients, which are printed on food labels in Canada and the United States.
Creating the Values
The Food and Nutrition Board has created RDA values for all essential nutrients, based on both gender and age. First, a review of available scientific literature is done, and from that the EAR (estimated average requirement) values are created; these meet the nutrient requirements of approximately half of the population in a certain age group. The RDA values are then calculated by adding two standard deviations to the EAR values.
The United States began creating RDA values in the 1940s, with the values being typically reviewed every 5 to 10 years. However, in the past few years, North America has incorporated the RDA values into a broader set of dietary guidelines called the Dietary Reference Intake (DRI).