Nutrition and protein turnover in man.

Abstract

The healthy young adult synthesizes and degrades at least 200 g of tissue protein each day (Waterlow et al., 1978a). By comparison, the dietary intake of protein is typically only one-third of this value. Measurements in man and in a number of other species have shown that there is an approximate parallelism between the rate of protein turnover by the whole body and a number of other metabolic parameters, such as the requirement for dietary protein (Young et al., 1975) and basal energy expenditure (Munro, 1964; Waterlow, 1968). Indeed, the expenditure of metabolic energy is required for the formation of peptide bonds; at a conservative estimate, the energy cost of protein synthesis accounts for 20% of oxygen consumption.