Infant vitamin B-6 status changes with age and with formula feeding.

To study the effect of type of feeding on infant vitamin B-6 status, we determined erythrocyte pyridoxal 5'-phos- phate concentration (EPLP) and erythrocyte aspartate amino- transferase basal activity (EASTO) and its activation coefficient (aEAST) in 109 infants at 2, 4, 6, 9, and 12 mo of age. Thirty- six infants were exclusively breast-fed for 9 mo. Forty-six infants were exclusively breast-fed for 6 mo, and then given solid foods in addition. Twenty-seven infants were weaned by 2-3 mo to an adapted cow milk-based formula (15 g proteinlL and 0.6 mg pyridoxinelL) and given solid foods from 3 to 4 mo. Infant vita- rain B-6 status was age-dependent; it was highest at 4 mo and thereafter gradually approached adult values. The larger the in- take of formula, the higher the vitamin B-6 status. In formula- fed infants at ages 2-6 mo, 71-96% of the EPLP values and 57-70% of the EASTO values were above the 95th percentile, and 35-53% of the aEAST values were below the 5th percentile for these values in breast-fed infants. These findings raise the question of whether the vitamin B-6 content of formulas, espe- cially in relation to protein content, should be reduced. Am J Clin Nutr l994;60:907-lO.