Zinc transfer to the breastfed infant

Zinc is a micronutrient which is critical to normal growth and development. Zinc concentrations in human milk decline sharply during the early months post partum, regardless of maternal zinc intake. Milk zinc concentrations d o not increase in response to increased maternal zinc intake if maternal zi nc status is adequate. The mechanism of zinc secretion into milk is not ful ly understood. A mutation in the gene for a zinc transporter protein may ac count for abnormally low milk zinc concentrations associated with severe zi nc deficiency in breastfed infants. The zinc requirements of breastfed infa nts are generally met with exclusive breastfeeding through 5-6 months of ag e, due to the favorable bioavailability of the zinc in human milk. Because of declining milk zinc concentrations and intake, zinc status in exclusivel y breastfed infants is likely to become marginal beyond 6 months of age, an d may become suboptimal for some infants if exclusive breastfeeding continu es. The choice of complementary foods is important to maintain adequate zin c status in breastfed infants after 6 months.