ARS | Publication request: Breast milk vitamin B-12 concentrations of Guatemalan women are correlated with maternal but not infant vitamin B

Submitted to: Journal of Nutrition
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: October 22, 2011
Publication Date: N/A

Interpretive Summary: Vitamin B-12 deficiency is emerging as a public health concern in many developing countries. In our previous studies in Guatemala, one third of lactating women, infants and children had deficient or marginal vitamin B-12 status. The goal of this study was to determine the relationship between maternal B-12 status, the concentration of the vitamin in her breast milk, and how breast milk B-12 related to infant B-12 status. Participants were 183 pairs of lactating women and their breastfeeding infants at 12 months postpartum; breastfeeding occurred 12 times a day on average. Information was collected on maternal and infant anthropometry, serum vitamin B-12 and dietary B-12 intake. Breast milk vitamin B-12 was measured after removal of haptocorrin, a strong binder of the vitamin which in the past has invalidated most assays used to measure B-12 in human milk. Vitamin B-12 deficiency (serum B-12 <150 pmol/L) was found in 35% of mothers and 27% of infants, and marginal status (15-220 pmol/L) in 35% of mothers and 17% of infants. In a multiple regression analysis, breast milk vitamin B-12 was significantly correlated with maternal intake of the vitamin (r=0.26) and maternal serum B-12 (r=0.30). Infant serum B-12 was correlated with maternal serum B-12 (r=0.31) implicating a long-term influence of maternal status on the infant. However infant status was not related to breast milk B-12 because the infants’ intake of the vitamin from complementary food was higher than they obtained from breast milk, which was very low in the vitamin.

Technical Abstract: In our previous studies one third of lactating Guatemalan women, infants and children had deficient or marginal serum vitamin B-12 concentrations. Relationships among maternal and infant status and breast milk vitamin B-12, however, have not been investigated in such populations. Our purpose was to measure breast milk vitamin B-12 in Guatemalan women with a range of serum vitamin B-12 concentrations, and to explore associations between milk vitamin B-12 concentrations and maternal and infant vitamin B-12 intake and status. Participants were 183 mother-infant pairs, breastfeeding at 12 mo postpartum. Exclusion criteria included mother <17 y, infant <11.5 or >12.5 mo, multiple birth, reported health problems in mother or infant, and mother pregnant >3 mo. Data collected on mothers and infants included anthropometry, serum and breast milk vitamin B-12, and dietary vitamin B–12. Serum vitamin B-12 concentrations indicated deficiency (<150 pmol/L) in 35% of mothers and 27% of infants, and marginal status (150 to 220 pmol/L) in 35% of mothers and 17% of infants. In a multiple regression analysis, breast milk vitamin B-12 concentration was correlated (P<0.05) with both maternal vitamin B-12 intake (r=0.26) and maternal serum vitamin B-12 (r=0.30). Controlling for number of breastfeeds/d and vitamin B-12 intake from complementary foods, infant serum vitamin B-12 was correlated with maternal serum vitamin B-12 (r=0.31, P<0.001) but not breast milk vitamin B-12, implicating a long-term effect of pregnancy status on infant vitamin B-12 status at 12 mo postpartum.