[Vitamin A status in full-term and premature infants]

Abstract

Vitamin A status has been assessed by studying plasma vitamin A and retinol binding protein (RBP) levels in premature infants receiving 7,500 IU vitamin A/d (RDA 660-3,300 IU/d) and in control term babies during the 3 first months of life. Sampling was performed within the first week (D0-D7), between the 8th and the 30th day (D8-D30) and during the 2nd and the 3rd month of life (M2-M3). At D0-D7, vitamin A levels of the PTI group (28-32 weeks gestational age), PTII (33-36 weeks GA) and AT (control term newborn) were 242.1 +/- 20.5 (X +/- SEM), 176.1 +/- 12.3 and 213.1 +/- 17.1 micrograms/l respectively (P = 0.005). At D8-D30, these values were 264.2 +/- 26.0, 270.4 +/- 21.6 and 242.6 +/- 24.5 micrograms/l respectively (NS), and at M2-M3 234.2 +/- 21.6, 282.1 +/- 18.5 and 292.1 +/- 31.5 micrograms/l (NS). A significant difference was found between the values of the different dosage periods for PTII and AT groups; no difference in RBP levels was found either between groups or between dosage periods. At birth, our results show that the RBP synthesis is not closely linked to gestational age. The plasma vitamin A levels which rely on foetal stores and therefore on transplacental passage and on peripheral tissue requirements are low at 33-36 weeks gestational age. With a 7,500 IU daily supplement, excessively high vitamin A levels were not observed in premature infants; vitamin A and RBP levels in premature infants receiving supplement are not different from controls despite the 8-12-week term high vitamin A supply.