Abstract
Background: Iron deficiency (ID) is the most prevalent nutritional deficiency worldwide and remains a major public health concern, particularly during pregnancy, infancy, and early childhood. Because iron is essential for brain development, both insufficient and excessive iron exposure during critical developmental periods may have lasting effects on neurodevelopment. Objective: This study aims to review the available evidence on the effects of iron status and iron supplementation (IS) during early life on neurodevelopmental outcomes. Methods: A review was conducted in accordance with the PRISMA 2020 guidelines. Six electronic databases were searched independently by two reviewers. Studies investigating the association between iron status or IS and neurodevelopmental outcomes in infants and children were selected according to predefined eligibility. Results: The search identified 884 records, of which 15 studies met the inclusion criteria. The available evidence indicates that ID during pregnancy and early childhood is associated with poorer cognitive, motor, language, and behavioral outcomes, with some studies reporting effects that persist into later childhood and adulthood. IS reduced the risk of ID and iron deficiency anemia (IDA) in vulnerable populations. However, in children with adequate iron stores, excessive iron exposure was associated with less favorable neurodevelopmental outcomes in several studies. Conclusions: Maintaining adequate iron status during early life is essential for optimal neurodevelopment. The findings support targeted supplementation strategies in populations at risk of deficiency and highlight the importance of appropriate screening using biomarkers such as ferritin, hemoglobin, and inflammatory markers, including C-reactive protein. Additional longitudinal studies are needed to define the long-term neurodevelopmental effects of different supplementation strategies.