Serum Amino Acid Concentrations in Infants from Malawi are Associated with Linear Growth

Serum amino acid (AA) concentrations are correlated with childhood stunting, but their relation to linear growth velocity has not been explored. This was a secondary analysis of a clinical trial where Malawian infants aged 6-12 mo were given a legume supplement providing 8.2 g/d of protein; anthropometry was conducted at multiple intervals, and fasted serum AA concentrations were measured at 12 mo of age. Lysine, proline, tryptophan, tyrosine, and valine concentrations were higher in infants with a linear growth velocity z-score >0 than those <0. Corrected Spearman correlation coefficients between individual AA concentrations and weight-for-height and length velocity from 6 to 12 mo of age were positively correlated for glycine, isoleucine, proline, serine, threonine, tyrosine, and valine. Additionally, weight-for-height was correlated with arginine, asparagine, glutamine, leucine, lysine, methionine, and phenylalanine. The observed associations suggest that testing the hypothesis that essential AA provision will reduce linear growth faltering is warranted. This trial was registered at clinicaltrials.gov as NCT02472262.