The Growth and Maintenance Utilization of Dietary Protein

Abstract

A study has been made of the growth and maintenance utilization of four crude protein sources covering a wide range of nutritive qualities. When the level of protein intake is increased there is a decline in the fraction of absorbed protein that is utilized for maintenance. At the same time the fraction utilized for growth rises to a maximum and then declines. The net result of these changes is a fall in the biological value. The relative participation of growth and maintenance in making up the biological value varies markedly depending upon the quantity and the nutritive quality of protein that is ingested. Since the protein requirements for growth and maintenance are different the conclusion is drawn that these two factors should be measured independently and not in combination.