Iron deficiency (ID) remains the most prevalent nutritional deficiency worldwide and a major cause of morbidity in childhood. This review outlines the physiological basis, risk factors, consequences, and prevention strategies for ID and iron deficiency anemia (IDA) in infants, young children, and adolescents. Childhood includes two critical periods of heightened vulnerability—infancy/early childhood and adolescence—when rapid growth markedly increases iron requirements. Preterm birth, low birth weight, exclusive breastfeeding beyond 4–6 months without supplementation, early introduction of cow’s milk, poor dietary habits, menstrual blood loss in adolescent girls, and rapid pubertal growth in boys are identified as key contributors to negative iron balance. Beyond hematologic changes, ID can impair neurodevelopment, cognitive performance, immune function, and behavior, with some deficits persisting long-term even after treatment. Early recognition is essential, and serum ferritin combined with inflammatory markers (CRP) and transferrin saturation represent the most reliable diagnostic indicators. Preventive measures—including delayed cord clamping, timely introduction of iron-rich complementary foods, iron supplementation for at-risk groups, and limiting cow’s milk intake—are crucial to reducing the global burden of ID. Despite advances in understanding its physiology and management, iron deficiency in childhood remains a significant public health challenge requiring targeted screening and effective preventive strategies.

Iron deficiency, children, anemia, prevention