POSSIBLE ANTIOXIDANT EFFECT OF VITAMIN-A SUPPLEMENTATION IN PREMATURE-INFANTS

Background: Increased lipid peroxidation caused by oxygen free radical s is thought to be one of the common pathogenetic mechanisms for the s o-called oxygen radical diseases of prematurity. Since in vitro studie s have shown that various forms of vitamin A can exert antioxidant eff ects that are more potent than those of vitamin E (treatment with whic h has been ineffective in these diseases), the purpose of this prospec tive, controlled study was to determine whether administration of supp lemental vitamin A to premature infants deficient in this vitamin woul d have an antioxidant effect in vivo. Methods: Fourteen infants (1181 +/- 35 g; gestational age 29 +/- 0.04 weeks) with a serum retinol conc entration at 7 +/- 2 days of age in the deficient range, lower than 0. 7 mu mol/l (<20 mu dl), were enrolled in the study. Infants were rando mized to receive the standard amount of vitamin A or standard plus sup plemental (2.6 mu mol/l [2500 IU] orally each day) vitamin A, beginnin g at 1 week of age. Antioxidant effects of supplementation were assess ed by decrease in lipid peroxidation, quantified by the ethane content of expired air. Results: Three weeks after study enrollment, total da ily vitamin A intake in the infants receiving supplements was 4.565 +/ - 0.236 mu mol (3354 +/- 225 IU) versus 1.879 +/- 0.317 mu mol/l (1792 +/- 307 IU) in infants receiving standard amount, of the vitamin. In spite of the difference in intake of vitamin A, 3 weeks after study en rollment, serum retinol concentrations did not differ between the infa nts given supplements and those receiving standard amounts of vitamin A, 0.70 +/- 0.21 versus 0.66 +/- 0.07 mu mol/l (20 +/- 6 mu g/dl versu s 19 +/- 2 mu g/dl, respectively). In the infants receiving supplement al vitamin A, breath ethane values declined from baseline values, Ther e was an inverse correlation between the number of weeks of supplement ation and breath ethane values, whereas there was no significant corre lation between the duration of the study and breath ethane values in t he infants not given supplements. Conclusions: Our data suggest that s upplementation with vitamin A in a small group of vitamin A-deficient preterm infants was associated with an antioxidant effect. Although no immediate clinical benefits were associated with supplementation, the data provide the rationale for future investigations of possible anti oxidant effects of (larger amounts?) of vitamin A in higher risk prema ture infants born with subnormal serum retinol concentrations. (C) 199 7 Lippincott-Raven Publishers.