Vitamin B6 intake and plasma pyridoxal phosphate concentrations in the first 2 weeks of life.

Plasma pyridoxal phosphate concentrations were measured in 178 hospitalised neonates. A reference interval for neonates less than 7 day old, of 25 to 78 nmol/l has been established. Vitamin B6 intakes did not correlate well with plasma pyridoxal concentrations despite 26 neonates receiving less than the Recommended Allowance (0.3 mg/d) and 19 receiving amounts below which convulsions have been associated (0.1 mg/d). Ten percent of those infants fed breast milk had plasma pyridoxal phosphate levels below the reference interval compared with only 4% of those fed milk formulae. Breast milk from mothers with babies less than 14 days old had a total vitamin B6 contents reference interval of 5 to 40 micrograms/l. Twenty percent of breast milk samples had virtually no vitamin B6 detected.