Revista Fisio&terapia · Jun 10, 2026
The impact of iron deficiency on human cognitive performance: a meta-analysis of the scientific literature
By Costa HMC, Gatto I, Gonçalves JR et al.
Introduction: Iron deficiency is the most common nutritional deficiency worldwide and affects cognitive functions by impairing neurotransmitter synthesis and brain metabolism. Evidence associates iron deficiency with impairments in memory, attention, and learning, particularly in children. Socioeconomic factors aggravate the problem, and the effectiveness of interventions still requires further investigation. Objectives: To evaluate the impact of iron deficiency on cognition by identifying diagnostic methods, effects on cognitive functions, age-related differences, and clinical and public health implications. Methodology: This meta-analysis, based on the PRISMA 2020 protocol, evaluated recent studies on iron deficiency and human cognition. Laboratory markers, cognitive tests, and control factors were analyzed through a systematic search of scientific databases and rigorous study selection based on eligibility criteria and methodological quality. Results: The review identified 8,932 records, of which seven studies met the inclusion criteria. The findings demonstrated that iron deficiency impairs memory, attention, intelligence, and executive functions across different stages of life. In children, iron supplementation significantly improved cognitive performance, especially in the presence of anemia. In adolescents, low ferritin levels were associated with poorer academic performance. Even in the absence of anemia, iron deficiency was linked to cognitive impairment and cognitive improvement following supplementation. In older adults, iron deficiency was associated with accelerated cognitive decline and an increased risk of dementia. The effects varied according to age, sex, comorbidities, and socioeconomic context, highlighting the importance of early diagnosis, assessment beyond hemoglobin levels, and timely interventions to minimize cognitive impacts throughout life. Final Considerations: This meta-analysis demonstrated that iron deficiency affects cognition across all stages of life, including individuals without anemia. The results revealed impairments in memory, attention, and executive functions, indicating that reversibility depends on age, duration of deficiency, and the timing of therapeutic intervention.