Subclinical Iron Deficiency in Athletes - Diagnostics, Consequences, and Management Strategies: A Narrative Review
DOI:
https://doi.org/10.12775/JEHS.2026.88.69380Keywords
iron deficiency, non‑anemic iron deficiency, ferritin, athletes, sports performance, hepcidin, iron supplementation, endurance trainingAbstract
Background:Subclinical iron deficiency is common in physically active populations,especially among female and endurance athletes, and may impair oxygen transport,mitochondrial energy production,and training adaptation before anemia develops.Exercise-related mechanisms (hemolysis,gastrointestinal loss,hepcidin-mediated reduced absorption) and dietary factors contribute to chronically low iron stores.Aim:To summarize evidence on diagnostic criteria,physiological and performance-related consequences,and management strategies for subclinical iron deficiency in athletes.Methods:A narrative review of peer-reviewed human studies was conducted using PubMed, Scopus,Web of Science,SPORTDiscus,CINAHL,and the Cochrane Library.Studies in competitive or highly trained athletes reporting diagnostic approaches,prevalence,performance or health outcomes,or management strategies were included.Results:Diagnostic criteria vary, with ferritin cut-offs of 20 - 40 μg/L most often used and limited consensus on sport-specific thresholds or routine use of transferrin saturation,soluble transferrin receptor,and hepcidin.Non-anemic iron deficiency affects ~35% of male and up to 60% of female athletes, with the highest prevalence in adolescents and endurance or aesthetic sports. Low iron stores are linked to reduced endurance, lower maximal aerobic capacity, increased fatigue, and possibly blunted training adaptation,while effects on anaerobic performance are inconsistent. Management emphasizes periodic screening,dietary strategies to improve iron bioavailability,and targeted oral supplementation timed to limit hepcidin-related malabsorption; intravenous iron is reserved for selected cases. Conclusions:Subclinical iron deficiency is common,under-recognized, and clinically relevant in athletes. Standardized,sport-specific diagnostic criteria,early screening,and individualized,evidence-based interventions delivered by multidisciplinary teams are essential for effective prevention and management.
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Copyright (c) 2026 Mikołaj Olszok, Daniel Wijas, Michał Kluś, Bartłomiej Kozdra, Natalia Makselan, Natalia Nawrat, Karolina Handzel, Antoni Anczyk, Krzysztof Karbowiak
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