Many vitamins and minerals have antioxidant properties. For many vitamins and minerals, scientific committees have established recommended intakes. A Requirement is the level of nutrient that an individual requires for efficient functioning.
A Recommended Intake is the level of a nutrient that is set to ensure that the majority of a healthy population will be meeting their individual requirement. These are referred to as Recommended Dietary Allowances (RDA), Recommended Nutrient Intakes (RNI) and Reference Nutrient Intakes (RNI). These essentially mean the same thing.