Zinc and breastfed infants: If and when is there a risk of deficiency?

Abstract

Infancy is a time of relatively high zinc requirements. Human milk provides an excellent source of highly bioavailable zinc and generally meets the needs of the healthy young exclusively breastfed infants for the first several months of life. Investigations of exclusively breastfed infants less than 6 mo of age have generally found zinc homeostasis and status to be adequate, although there are indications that zinc intake from human milk alone may become limiting by around 6 mo of age. Exceptions may be small for gestational age and low birth weight infants, who may well benefit from increased zinc intake before 6 mo of age. The older infant clearly becomes dependent on non-human milk sources of zinc, i.e., from complementary foods. Traditional early complementary foods, such as cereals, fruits, and vegetables provide very modest amounts of zinc, and for those high in phytic acid, bioavailability may be low. Introduction of animal products or zinc supplementation may be important to meet the older infant's zinc requirements. This is likely to be particularly important in less protected environments with a high infectious burden and limited dietary options.