Breast milk is low in iron, and infants may develop iron deficiency anemia by six months, necessitating iron-rich complementary foods.

“iron is an essential nutrient that plays key roles in infant growth but breast milk is incredibly low in iron which might seem counterintuitive however microbes require iron for their growth too to prevent infection the body restricts microbes access to iron within hours of birth the infant's serum iron levels drop dramatically this reduces the infant's risk of developing neonatal sepsis a generalized life-threatening bacterial infection that commonly occurs within the first days and weeks of life infants rely on their iron stores but by the age of six months infants can begin to develop iron deficiency anemia so pediatricians recommend introducing iron-rich complementary foods at that time”