Nutrient dietary requirements and reference values
Chapter 1 outlined the list of essential nutrients but guidance is needed over how much of each to consume. In the past, recommended daily intakes (RDI) of nutrients were established for the UK. The RDI was defined as ‘the amount sufficient or more than sufficient to meet the nutritional needs of practically all healthy people in a population’. However, as this definition might be interpreted as referring to amounts that individuals must consume rather than averages relating to a group of people, it was later replaced by a recommended daily amount (RDA). This is defined as ‘the average amount of the nutrient which should be provided per head in a group of people if the needs of practically all members of the group are to be met’.