Breast Milk Zinc Transfer to Appropriate‐ for‐Gestational‐Age (AGA) and Small‐for‐Gestational‐Age (SGA) Bangladeshi Infants: Studies of Milk Volume, Using Deuterium‐To‐Mother, and Milk Zinc Concentrations

Abstract

ObjectiveTo measure breast milk zinc transfer by mothers of AGA and SGA infants.MethodsWe studied breast milk transfer (using the deuterium “dose‐to‐the‐mother” technique) and milk zinc concentration of 73 mother‐infant pairs (33 AGA, 40 SGA) at 4, 12 and 24 wks post‐partum. In each round, 30 g deuterium was given orally to the mother following baseline blood and saliva collection from mothers and infants. Saliva samples were then obtained for deuterium analysis on days 1, 2, 3, 4, 13, and 14 from infants and days 1, 2, 13 and 14 from mothers. Breast milk zinc concentration was measured in milk collected at baseline and day 4 each round.ResultsBreast milk intake increased significantly with infant age (643 ± 190; 756 ± 150; 804 ± 150 g/d at 4, 12 and 24 weeks, respectively; p=0.000), and differed by birth weight (BW) groups only at 4 weeks post‐partum (AGA = 714 ± 193 vs SGA = 579 ± 164 g/d; p=0.005). Milk zinc concentration decreased significantly from 2.46 mg/L at 4 weeks to 1.02 mg/L at 24 weeks (p=0.000), but did not differ by BW group at any time point. Zinc transfer through breast milk declined significantly with infant age (1.60 ± 0.62; 1.08 ± 0.41; 0.81 ± 0.32 mg/d at 4, 12 and 24 weeks respectively; p=0.000), but did not differ by BW group.ConclusionsMilk zinc concentrations and total milk zinc transfer of Bangladeshi mothers are consistent with published data, and do not differ for mothers of AGA and SGA infants.