Vitamin B-6 adequacy in neonatal nutrition: associations with preterm delivery, type of feeding, and vitamin B-6 supplementation.

Concerns about vitamin B-6 adequacy in neonatal nutrition relate to critical functions of the vitamin in development. Vitamin B-6 status was assessed in six groups of neonates: two groups each of breast-fed term and preterm infants whose mothers were supplemented with 2 or 27 mg pyridoxine-hydrochloride (PN-HCl); a subgroup of term infants (2-mg maternal group) supplemented with 0.4 mg PN-HCl/d; and a formula-fed preterm group. During the 28-d experimental period, weekly assessments showed lower concentrations of total vitamin B-6 and percentages of pyridoxal in milk from mothers of preterm infants than in milk from mothers of term infants, even when maternal PN-HCl supplementation was 27 mg/d. The vitamin B-6 concentration of milk and estimated intakes of the vitamin by breast-fed infants paralleled maternal supplements (ie, 2 and 27 mg). Plasma and erythrocyte measurements of infants correlated with their vitamin B-6 intakes; values were highest for infants given vitamin B-6 supplements and those that wee formula-fed. Vitamin B-6 adequacy was questionable for unsupplemented breast-fed infants of mothers in the 2-mg supplemented groups.