The Systemic Availability of Indispensable Amino Acids from Orally Ingested Algal and Legume Protein in Young Children at Risk of Environmental Enteric Dysfunction

The digestion and absorption of ingested protein may be reduced in children with environmental enteric dysfunction (EED), reducing systemic amino acid availability for protein synthesis with resultant growth faltering. This has not been directly measured in children with EED and associated growth faltering. To evaluate the systemic availability of algal (spirulina) and legume (mung bean) indispensable amino acids (IAAs) in children with EED. Indian children (18–24 mo) from urban slums were assigned to EED (n = 24) or no-EED (control, n = 17) groups based on the lactulose rhamnose test, where the lactulose rhamnose ratio cutoff for diagnosing EED (≥0.068) was the mean + 2SD of its distribution in healthy, age-, and sex-matched children of high socioeconomic status. Fecal biomarkers of EED were also measured. Systemic IAA availability was calculated from the plasma: meal IAA enrichment ratio for each protein. True ileal mung bean IAA digestibility was measured by the dual isotope tracer method using spirulina protein as reference. Co-administration of free 13C6-phenylalanine allowed for estimating true ileal phenylalanine digestibility of both proteins, and a phenylalanine absorption index. There was no significant difference (independent t-test) in the systemic IAA availability from spirulina or mung bean protein between EED and no-EED groups. There was no between-group difference in true ileal phenylalanine digestibility and its absorption index, or in mung bean IAA digestibility. The systemic IAA availability of algal and legume protein, or the latter’s IAA/phenylalanine digestibility, is not significantly reduced in children with EED and does not correlate with linear growth. This study was registered in Clinical Trials Registry of India (CTRI) with registration number: CTRI/2017/02/007921.