ABSTRACT
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.
Subject(s)
Infant Nutritional Physiological Phenomena/physiology , Infant, Premature/physiology , Pyridoxine/administration & dosage , Adolescent , Adult , Alanine Transaminase/blood , Bottle Feeding , Breast Feeding , Child Development/physiology , Eating , Female , Gestational Age , Humans , Infant Food/standards , Infant, Newborn , Infant, Premature/blood , Milk, Human/chemistry , Nutritional Requirements , Pyridoxal Phosphate/blood , Pyridoxine/analysisABSTRACT
Vitamin B-6 concentrations in human milk are known to respond rapidly to changes in maternal vitamin B-6 intake. In this study, mothers were supplemented during the first 28 d of lactation with 2 or 27 mg pyridoxine (PN)-HCl/d and a subgroup of breast-fed infants of the 2-mg/d-supplemented mothers were supplemented with 0.4 mg PN-HCl/d. Vitamin B-6 intakes of breast-fed infants reflected the amount of their mother's supplement; intakes were highest for the vitamin-supplemented infants. Vitamin B-6 intake of mothers was a strong indicator of infant vitamin B-6 status. Vitamin intake of infants correlated significantly with five measures of vitamin B-6 status. Plasma pyridoxal-5'-phosphate (PLP) concentrations and birth weight were the strongest predictors of infant growth that were examined. Alkaline phosphatase activity in the mother's milk and infant plasma reflected pyridoxal-PLP ratios in these fluids, suggesting that the enzyme acts in regulating circulating vitamer concentrations.
Subject(s)
Breast Feeding , Milk, Human/chemistry , Pyridoxine/administration & dosage , Pyridoxine/blood , Adult , Alkaline Phosphatase/analysis , Birth Weight , Erythrocytes/chemistry , Female , Growth , Humans , Infant, Newborn , Lactation/drug effects , Nutritional Status , Pyridoxine/analysisABSTRACT
Pyridoxal 5'-phosphate (PLP) is a coenzyme in many metabolic transformations of amino acids and may play a role in their absorption and transport. This investigation analyzed the effects of large oral doses (27 mg/d) of pyridoxine (PN)-HCl over 2 wk on plasma PLP and amino acid concentrations in 10 young women. Plasma PLP was 45 +/- 2 nmol/L (means +/- SE) initially and reached 377 +/- 12 nmol/L after 7 d of supplementation. A steady-state PLP concentration remained as long as daily PN-HCl supplementation was continued. Plasma glutamic acid concentration was significantly lower after 7 and 14 d of supplementation whereas alpha-amino-N-butyric acid, alanine, cysteine, arginine, phosphoserine, and urea concentrations were significantly higher, particularly alpha-amino-N-butyric acid and cysteine. Altered plasma amino acid profiles and increased plasma urea concentrations in response to supplementation suggested accelerated protein and/or amino acid metabolism.
