American Journal of Clinical Nutrition, Vol 9, 356-362, Copyright © 1961 by The American Society for Clinical Nutrition, Inc.

Relationship Between Plasma Amino Acids and Composition of the Ingested Protein

II. A Shortened Procedure to Determine Plasma Amino Acid (PAA) Ratios

¹ From the Electrochemicals Department, Research Division, E. I. du Pont de Nemours and Company, Wilmington, Delaware

A previous report presented an in vivo plasma amino acid (PAA) ratio technic to evaluate the amino acid adequacy in a food protein for the nourishment of the dog. A modification of the original method is presented which reduces by approximately 60 per cent the time and amount of blood required for each experiment. The applicability of this procedure for human studies is demonstrated. The reproducibility of the PAA ratios is shown with the variation from subject to subject being significantly greater for some amino acids than the variation for the same subject. These findings may reflect individual differences in protein utilization and/or amino acid requirements and/or protein nutritional status. Experimentation with subjects under stress, e.g., illness, malnutrition, should be quite promising.