EFFECT OF DIFFERENT VITAMIN-A INTAKES ON VERY-LOW-BIRTH-WEIGHT INFANTS

Formula-fed infants with birth weights less than or equal to 1500 g (n = 61) were stratified by 250-g birth-weight ranges and randomly assig ned to receive one of three preterm infant formulas (vitamin A content s of 820 TU, 1640 IU, or 2900 IU/MJ; 1 RE = 3.3 IU vitamin A activity) when subjects tolerated 0.314, MJ . kg(-1). d(-1). Experimental formu la feedings were continued until infants weighed approximate to 2 kg o r until hospital discharge. Vitamin A status as indicated by serum ret inol and retinol-binding protein (REP) concentrations significantly de creased during experimental formula feeding at the lowest vitamin A in take. All subjects fed the formula providing the lowest vitamin A inta ke had hyporetinolemia (< 0.70 mu mol/L, or < 20 mu g/dL), which occur red less frequently (P < 0.05) with the intermediate (6 of 20) and the high (6 of 21) vitamin A intakes. Other outcome measures, including i ncreases in weight, length, and head circumference, and ventilatory su pport and oxygen therapy, were not different among groups. After the e nd of the experimental formula-feeding period, all infants were fed st andard infant formulas with a vitamin A content of 715 IU/MJ. In a sub set of 19 of these infants, subsequent vitamin A status was monitored at ages 6-12 mo and was found to be comparable with that of older chil dren and adults, regardless of the vitamin A content of the formula fe d during hospitalization. It is concluded that very-low-birth-weight ( VLBW) infants receiving preterm infant formula providing a Vitamin A i ntake < 400 IU . kg(-1). d(-1) until they achieved a body weight of 2 kg had significantly lower serum retinol and lower REP concentrations compared with infants fed formulas with a higher vitamin A content. Lo ngitudinal follow-up of these preterm infants showed improved vitamin A status with increasing postnatal age, regardless of the amount of vi tamin A intake until they reached a body weight of 2 kg.