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 C- 13 tyrosine breath test was developed for the measurement of tyrosine catabolism. Premature babies were randomly allocated to receive a dail y intake of vitamin C which ranged from 8 to 100 mg/kg body weight, fo r 5 days. Tyrosine catabolism was measured at the beginning and the en d of this period. Daily intakes of vitamin C of 20 mg/kg or more elici ted a greater increase in tyrosine catabolism over 5 days than 8 mg/kg /day. The magnitude of the difference, in terms of percentage of tyros ine metabolised, was, however, small and of doubtful biological signif icance. Vitamin C intakes above 20 mg/kg/day had no further measurable effect on the catabolism of tyrosine.