Calcium needs are great during infancy as this is a period of rapid skeletal growth and mineralization. The calcium of breast milk is well absorbed whereas that of formula, though more in quantity than breast milk, is not as well absorbed. However both sources meets the infants requirement. Excessive phosphorus relative to calcium may contribute to calcium loss from the bone. Both breast milk and infant formula meet the infants needs optimally.
Breast milk contains relatively small amounts of iron (0.5mg/1000ml) which is highly bioavailable (50%). The iron content of infant formula is higher but bioavailability is lower (4%). The full term infant has sufficient stores and therefore does not need much iron till about six months of age. At six months, if the infant does not receive sufficient iron there is a possibility of his becoming anemic. Iron deficient infants display symptoms of irritability, anorexia and poor weight gain. Sometimes these behavioural changes tend to persist in childhood also. Iron deficiency is the most common nutrient deficiency among infants and should be a high priority for all those caring for infants.
A deficiency of zinc impairs growth. The zinc content of breast milk is sufficient to meet an infants needs till one year, if the mother’s intake is adequate.