Nitrogen Balances of Young Men Fed Selected Amino Acid Patterns: I. Fao Reference Pattern, a Modification of the Fao Reference Pattern, and Wheat Flour Pattern

Abstract

Nitrogen balances were determined for six young men fed three amino acid patterns : the F A 0 reference pattern, a modification of the F A 0 pattern in which methionine was decreased and phenylalanine increased isonitrogenously, and the wheat pattern. Total N intake was approximately 10 g. The lowest intakes of the F A 0 reference pattern amino acids found to be adequate for the support of N equilibrium or positive N balance contained 320 mg tryptophan in the case of two subjects, 280 mg tryptophan for three subjects, and 240 n~g tryptophan for one subject. Comparison of group mean N retentions for the F A 0 and the modified F A 0 patterns indicated that the two patterns were of equal value. When the F A 0 reference and wheat patterns were fed to provide comparable amounts of lysine, the limiting amino acid of wheat protein, group mean N retentions were 0.42 and 0.41 g, respectively. When the same two patterns were fed to provide an equivalent amount of essential amino acid N and the chief source of amino acids was intact wheat protein, group mean N retentions were 0.62 g for the F A 0 reference pattern, and 0.41 g for the wheat pattern; statistically, this difference is not significant. From 0.63 to 0.84 g essential amino acid N provided as F A 0 reference pattern was adequate to maintain N equilibrii~rn or a slight positive balance.