Tyrosine requirement during the rapid catch-up growth phase of recovery from severe childhood undernutrition.
The requirement for aromatic amino acids during the rapid catch-up in weight phase of recovery from severe childhood undernutrition (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.
Badaloo
Asha
A
Tropical Metabolism Research Unit, University of the West Indies, Mona, Kingston 7, Jamaica. asha.badaloo@uwimona.edu.jm
Hsu
Jean W-C
JW
Taylor-Bryan
Carolyn
C
Reid
Marvin
M
Forrester
Terrence
T
Jahoor
Farook
F
D002247:Carbon Isotopes; D005260:Female; D006801:Humans; D007223:Infant; D007225:Infant Food; D007228:Infant Nutrition Disorders / Q000178:diet therapy* / Q000378:metabolism*; D008297:Male; D044342:Malnutrition / Q000178:diet therapy*; D009751:Nutritional Requirements; D010649:Phenylalanine / Q000737:chemistry / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism*
D002247:Carbon Isotopes; D014443:Tyrosine; D010649:Phenylalanine