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Does vitamin C intake influence the rate of tyrosine catabolism in premature babies?
H J Powers1, A T Gibson, C J Bates
1Department of Paediatrics, University of Sheffield, UK.
Insights
Higher vitamin C intake in premature infants increased tyrosine catabolism, but the effect was minimal. Doses above 20 mg/kg/day showed no additional benefit for tyrosine metabolism.
Area of Science:
- Biochemistry
- Neonatal Nutrition
- Nutritional Science
Background:
- Premature infants have unique metabolic needs.
- Vitamin C (ascorbic acid) is essential for various physiological processes.
- Tyrosine metabolism is critical in neonatal development.
Purpose of the Study:
- To investigate the relationship between vitamin C intake and tyrosine catabolism in premature infants.
- To determine the optimal vitamin C dosage for influencing tyrosine metabolism in this population.
Main Methods:
- Development of a 13C tyrosine breath test for measuring tyrosine catabolism.
- Randomized allocation of premature infants to daily vitamin C doses (8-100 mg/kg) for 5 days.
- Measurement of tyrosine catabolism at baseline and after the 5-day intervention period.
Main Results:
- Daily vitamin C intake of 20 mg/kg or more resulted in a modest increase in tyrosine catabolism compared to 8 mg/kg/day.
- The observed increase in tyrosine catabolism was small and of questionable biological significance.
- Vitamin C doses exceeding 20 mg/kg/day did not yield further measurable effects on tyrosine catabolism.
Conclusions:
- Vitamin C supplementation in premature infants can influence tyrosine catabolism, but the effect is dose-dependent and plateaus.
- A daily intake of 20 mg/kg of vitamin C appears to be a threshold for observing a measurable impact on tyrosine catabolism.
- Higher vitamin C doses beyond 20 mg/kg/day do not provide additional benefits for tyrosine metabolism in premature infants, suggesting careful dosage considerations.
Abstract:
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.