The Effect of Certain Factors on Nitrogen Retention and Lysine Requirements of Adult Human Subjects

Abstract

The effect on nitrogen retention of varying the caloric intake when the diet provided quantities of lysine that equalled or exceeded minimum requirements was measured. Amino acids were present in purified form and as peptide-bound amino acids in cereals. Nitrogen balances of men and women were not altered by increasing the energy value of the diet above a critical level which differed for individuals. Reduction of calories below this point, however, caused a decrease in nitrogen retention, so that a subject who previously retained significant amounts of nitrogen might just maintain equilibrium or even be in negative balance.