(P07-023-23) Human Milk Zinc, Copper, and Selenium Concentrations at 3 Months Postpartum Among Bangladeshi Women: Associations With Maternal Plasma Mineral Concentrations

Objectives: Human milk zinc (Zn) and copper (Cu) concentrations are largely considered to be unaffected by maternal status of those nutrients, while milk selenium (Se) has been linked to dietary exposure. We measured milk concentrations of Zn, Cu, and Se at 3 months postpartum among Bangladeshi mothers to ascertain responsiveness to antenatal multiple micronutrient supplements (MMS) and relationships with maternal plasma mineral concentrations in early and late pregnancy and at 3 months postpartum.

Methods: JiVitA-3 was a cluster-randomized trial conducted in rural Bangladesh to compare MMS containing 1 RDA of Zn, Cu, and Se among other micronutrients to iron-folic acid alone as control provided during pregnancy to 3 mo postpartum. Maternal plasma was collected in early (pre-supplementation; ~10 wk gestation) and late pregnancy (~32 wk gestation) and 3 mo postpartum, as was a spot sample of breast milk, to access Zn, Se, and Cu in n=752 women. Descriptive statistics as mean±SD, intervention effects accounting for cluster-randomization, and associations of milk to plasma minerals with Spearman correlation are presented.

Results: Milk and plasma minerals did not differ by intervention. Milk Zn among all women was 1555±31 μg/L, while early and late pregnancy and postpartum plasma Zn was 735±10, 678±13, and 604±9 μg/L. Milk Cu was 302±4 μg/L, with plasma values of 1160±11, 1666±13, and 1093±8 μg/L, respectively. Milk Se was 13.3±0.2 μg/L, while plasma values were 84.4±0.5, 72.2±0.5, and 81.9 ±0.6 μg/L, respectively. Milk Zn was not related to postpartum (r=0.02, p=0.67) nor pregnancy Zn. Milk Cu was weakly inversely correlated with postpartum (r=-0.10, p=0.01) and early (r=-0.08, p=0.04) pregnancy Cu. Milk Se was positively correlated with plasma Se at early (r=0.20, p< 0.0001) and late (r=0.28, p< 0.0001) pregnancy and postpartum (r=0.45, p< 0.0001) periods.

Conclusions: Higher Zn but lower Cu and Se concentrations were observed in milk than in corresponding maternal plasma. Milk Zn and Cu did not respond to the MMS intervention and were unrelated or weakly inversely related to maternal status, respectively. While milk Se did not respond to MMS, positive correlations of milk Se with pregnancy and postpartum plasma values suggest a persistence of maternal status across reproduction that is reflected in milk Se.

Funding Sources: Bill and Melinda Gates Foundation