Myths vs facts: Ferritin Eisenmangel and Sport

Ferritin is the main iron storage protein. Low ferritin often indicates iron deficiency, but it is also an acute-phase reactant: inflammation or infection can elevate ferritin even when iron stores are low. In sports, iron deficiency is common, especially in endurance athletes, due to increased losses (sweat, foot-strike hemolysis, menstruation) and higher erythropoiesis. Myth: Any low ferritin level requires immediate supplementation. Fact: A full iron panel (serum iron, transferrin saturation, soluble transferrin receptor) plus inflammatory markers (CRP) is needed for accurate diagnosis. Iron supplements without proven deficiency can cause oxidative stress and impair absorption of other minerals. Evidence for performance improvement from iron supplementation in non-deficient athletes is weak. Conclusion: Ferritin is a useful but not standalone marker. Athletes should have their iron status assessed regularly and comprehensively.