Optimizing protein intake in adults: Interpretation and application of the recommended dietary allowance compared with the acceptable macronutrient distribution range

Abstract

The adult RDA is defined as the average daily level ofintake sufficient to meet the nutrient requirements of nearly all healthy people. The RDA for protein foradults ≥18 y of age (0.8 g/kg) has been essentially unchanged for>70y. In practice, the RDA for protein was derived to estimatethe minimum amount of protein that must be eaten to avoid a loss ofbody nitrogen.The Acceptable Macronutrient Distribution Range (AMDR) (1035% of calories as protein) was developed to expressdietaiy recommendations in the context ofacomplete diet. It is noteworthy that the lowest level of protein intake reflected in the AMDR is higher than that of the RDA. Furthermore, recent studies, particularly in older individuals, suggest specific health benefits at levels of protein intake that significantly exceed the RDA. Translation of protein intake recommendations for the general adult population into dietary guidance for individuals requires an understanding ofthe derivation and intended use of both the protein RDA and AMDR. The following discussion will describe limitations to the derivation and practical application ofthe RDA compared with the use ofthe AMDR to help maximize health benefits associated with higher protein intake by using flexible calories inherent in different dietary patterns.