Location: Children's Nutrition Research CenterTitle: Tyrosine requirement during the rapid catch-up growth phase of recovery from severe childhood undernutrition Author
Submitted to: British Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/19/2010
Publication Date: 10/1/2010
Citation: Badaloo, A., Hsu, J.W., Taylor-Bryan, C., Reid, M., Forrester, T., Jahoor, F. 2010. Tyrosine requirement during the rapid catch-up growth phase of recovery from severe childhood undernutrition. British Journal of Nutrition. 104(8):1174-1180. Interpretive Summary: When children are recovering from severe malnutrition, they use 20 compounds called amino acids to make new protein to lay down with the new tissue they are making. It is important to know exactly how much of each amino acid is needed by the child in order for it to grow new tissues at a fast rate. One of these amino acids is tyrosine. In this study, we found out that when a child is growing rapidly during recovery from severe malnutrition, the child needs a minimum of 98.8 mg of tyrosine per kilogram of body weight per day. Such findings are important as they provide possible targets for malnutrition recovery.
Technical Abstract: The requirement for aromatic amino acids, during the rapid catch-up in weight phase of recovery from severe childhood under nutrition (SCU) is not clearly established. As a first step, the present study aimed to estimate the tyrosine requirement of children with SCU during the catch-up growth phase of nutritional rehabilitation using a diet enriched in energy and proteins. Tyrosine requirement was calculated from the rate of excretion of 13CO2 (F 13CO2) during [13C] phenylalanine infusion in thirteen children with SCU, five females and eight males, at about 19 d after admission when the subjects were considered to have entered their rapid catch-up growth phase and were consuming 627.3 kJ, and about 3.5 g protein/kg per d. Measurements of F 13CO2 during [13C] phenylalanine infusion were made on two separate days with a 1 d interval. Three measurements at tyrosine intakes of 48, 71, and 95 mg/kg per d were performed on experimental day 1 and measurements at tyrosine intakes of 148, 195, and 241 mg/kg per d were performed on experimental day 2. An estimate of the mean requirement was derived by breakpoint analysis with a two-phase linear regression cross-over model. The breakpoint, which represents an estimate of the mean tyrosine requirement, is a value of 99 mg/kg per d when the children were growing at about 15 g/kg per d. The result indicates that the mean requirement for tyrosine during the catch-up growth phase of SCU is about 99 mg/kg per d under similar conditions to the present study.