Iron, Copper and Zinc Levels in Human Milk and Estimated Intake of the Minerals by Breast-Fed Infants during the Early Lactation

수유 초기 모유 중 철, 구리, 아연의 함량과 영아의 섭취량 추정

The objectives of the present study were to measure the content of iron, copper and zinc in human milk and to estimate the intake of iron, copper and zinc of breast-fed infants during the early period of lactation. Twenty-five lactating women who delivered in a hospital in Seoul volunteered for the study. Milk samples were collected at day 2, 3, 4, 5, 6, 7, 15 and 30 postpartum. The contents of iron, copper and zinc were determined using the atomic absorption spectrophotometer after wet digestion. The intakes of iron, copper and zinc of infants were estimated by multiplization with the infant milk intake reported in our laboratory. The content of iron was 0.58 $\mu\textrm{g}$/g in colostrum, 0.48 $\mu\textrm{g}$/g in transitional milk and 0.39 $\mu\textrm{g}$/g in mature milk while the estimated iron intake of infants was 271, 255 and 259 $\mu\textrm{g}$/day, respectively. The content of copper in the milk was 0.45 $\mu\textrm{g}$/g in colostrum, 0.43 $\mu\textrm{g}$/g in transitional milk and 0.33 $\mu\textrm{g}$/g in mature milk while the estimated copper intake of infants was 210, 229 and 220 $\mu\textrm{g}$/day, respectively. The content of zinc in the milk was 5.24 $\mu\textrm{g}$/g in colostrum, 3.70 $\mu\textrm{g}$/g in transitional milk, 2.93 $\mu\textrm{g}$/g in mature milk while the estimated zinc intake of infants was 2452, 1968, and 1949 $\mu\textrm{g}$/day, respectively. These results suggest that copper and zinc intake of infants are met to RDA but iron is not.