Progressive effects of protein-calorie malnutrition on serum free amino acids in infant and young adult nonhuman primates

Abstract

Serum amino acid profiles have been known to change when dietary protein restriction is instituted in animals and in man. In the present study, significant alterations were noted in infant monkeys observed over 14 weeks. Impressive but less dramatic changes were apparent in protein-restricted young adult monkeys observed over a much longer period. In general, essential amino acids were depressed (especially the branched-chain group) while nonessential amino acids tended to rise (especially glycine and alanine). Changes were most acute within the first 3 to 4 weeks of dietary restriction. Improvement in dietary protein content provided to young adults led to resumption of normal serum amino acid patterns. Level of available dietary protein and age of the animals clearly dictated the severity of amino acid imbalance observed.