Iron deficiency in children. Update on an old problem.

Over the past 25 years the incidence of iron deficiency anemia has decreased remarkably. This decline has resulted directly from a program of prevention that is based on a detailed understanding of iron lack in infants and children. However, iron deficiency without anemia--subtle iron deficiency--remains a problem. The negative impact of iron deficiency on brain function has recently been demonstrated in animal as well as human studies. The behavioral effects noted in infants and toddlers can be seen with subtle iron deficiency as well as with anemia. Although behavioral abnormalities in the very young appear to be correctable by iron treatment, prolonged iron deficiency may lead to irreversible effects on brain function. These recent findings should further encourage continued vigilance in preventing the old problem of iron deficiency.