Protein Quality and Growth in Malnourished Children

Protein quality refers to the amounts and ratios of essential amino acids in a food. Two methods most commonly used for determining protein quality are the protein digestibility-corrected amino acid score (PDCAAS) and the digestible indispensible amino acid score (DIAAS).

To use existing literature to compare different amino acid profiles and PDCAAS and DIAAS scores in individuals with acute inflammation and to assess their relationship with weight gain in children with severe acute malnourished (SAM).

A series stable isotope studies were previously conducted in children with SAM and acute infection, and these data were reviewed with respect to protein synthesis. Eleven published treatment trials for SAM with different therapeutic foods were analyzed to examine the relationship between protein quality scores with weight gain (g/kg/d). Protein scores were calculated with the PDCAAS and DIAAS amino acid reference patterns. A DIAAS score adjusted for the higher weight gain expected in malnourished children was also used. Bivariate correlation analysis was used to examine this relationship.

The protein kinetic data supported the hypothesis that a balance of amino acids that matches the composition of acute-phase proteins maximizes amino acid synthesis. Protein quality scores were highly correlated with the rate of weight gain in recovery from SAM, and the DIAAS scoring system adjusted for the higher expected weight gain had the strongest correlation with the observed weight gain.

Protein quality scores must account for physiologic status so that they better match with needs and thus better promote health.