Effects of different levels of vitamin B-6 supplementation on vitamin B-6 concentrations in human milk and vitamin B-6 intakes of breastfed infants

Abstract

Vitamin B-6 has been reported to vary in concentration in human milk in response to changes in maternal intake of the vitamin. This study examined the effects of such changes on the breastfed infants' intake of vitamin B-6. Lactating mothers received 0, 2.5, 10.0 or 20.0 mg pyridoxine·HCl (PN·HCl) for 3 consecutive days in addition to dietary sources. Dietary intakes of vitamin B-6 (x̄ = 1.8 ± 0.2 mg/day) were similar among the four groups. Vitamin B-6 was determined in milk samples from each feeding and milk intakes of infants were estimated by test-weighing. Nonsupplemented mothers had lower vitamin B-6 in their milk (93 ± 8 μg/L) and vitamin B-6 intake of their infants was lower (0.06 ± 0.01 mg/day) compared to other groups. Maternal supplementation with 2.5, 10.0 or 20.0 mg PN·HCl was paralleled by vitamin B-6 levels in milk of 192 ± 16, 247 ± 25 and 413 ± 45 μg/L, respectively, and by vitamin B-6 intakes of breastfed infants of 0.12 ± 0.02, 0.22 ± 0.02 and 0.28 ± 0.03 mg/day, respectively. When maternal intakes of vitamin B-6 approximated 20.0 mg/day, breastfed infants were unlikely to receive the current RDA of 0.3 mg vitamin B-6/day.