Based on research, target levels of nutrients have been determined which fulfil the body’s needs. These are called nutrient requirements. Nutrient requirements refer to the different nutrients needed by the body for energy, growth and repair, and protection from disease. They differ according to the age, gender, level of physical activity, height, weight, stage of life, and health status of each individual.
There are different measures for nutrient requirements, called Dietary Reference Intakes. One of them is the EAR: the Estimated Average Requirement. The EAR is a nutrient intake value that is estimated to meet the requirement of half the healthy individuals in a group (i.e. approximately 50% of people will require less, and 50% will require more).