Does vitamin C intake influence the rate of tyrosine catabolism in premature babies?
A study was conducted to investigate the relationship between vitamin C intake and the rate of tyrosine catabolism in premature babies. A 13C tyrosine breath test was developed for the measurement of tyrosine catabolism. Premature babies were randomly allocated to receive a daily intake of vitamin C which ranged from 8 to 100 mg/kg body weight, for 5 days. Tyrosine catabolism was measured at the beginning and the end of this period. Daily intakes of vitamin C of 20 mg/kg or more elicited a greater increase in tyrosine catabolism over 5 days than 8 mg/kg/day. The magnitude of the difference, in terms of percentage of tyrosine metabolised, was, however, small and of doubtful biological significance. Vitamin C intakes above 20 mg/kg/day had no further measurable effect on the catabolism of tyrosine.
Department of Paediatrics, University of Sheffield, UK.
H J
HJ
Powers
A T
AT
Gibson
C J
CJ
Bates
R A
RA
Primhak
J
J
Beresford
D001205:Ascorbic Acid / Q000008:administration & dosage* / Q000097:blood / Q000627:therapeutic use; D001944:Breath Tests; D002247:Carbon Isotopes; D006801:Humans; D007231:Infant, Newborn; D007234:Infant, Premature / Q000378:metabolism*; D010666:Phenylpropionates / Q000652:urine; D014443:Tyrosine / Q000097:blood / Q000378:metabolism*
D002247:Carbon Isotopes; D010666:Phenylpropionates; C001418:4-hydroxyphenyllactic acid; D014443:Tyrosine; D001205:Ascorbic Acid