Dietary zinc and iron sources, physical growth and cognitive development of breastfed infants.

Iron and zinc are trace minerals that are of critical importance to the young infant for normal growth and development. Exclusive feeding of human milk provides adequate amounts of both of these nutrients for normal term infants for approximately the first 6 mo. of life. Current recommendations for introduction of complementary foods at this age do not emphasize the order of introduction of specific foods because the infant's gastrointestinal tract is considered mature at this time. Consideration of nutritional needs at 6 mo. has generally focused on the increasing risk of iron deficiency the longer the diet is without an additional source of iron. Recently, there has been more recognition of the risk of zinc deficiency in the second half of the first year of life in breastfed infants. Review of common feeding practices indicates that early complementary foods are typically iron fortified but low in zinc. Several studies have now investigated the effects of meat as an earlier complementary food on iron and zinc status. Results of these studies, although requiring further verification, suggest that increased meat intake by breastfed infants >6 mo. old would adequately support both iron and zinc requirements.