Evidence check: Ferritin in the context of Sport

The provided context does not contain specific information on ferritin in sport. In general, ferritin is a key marker of body iron stores. In athletes, especially endurance athletes, low ferritin levels (e.g., <30 ng/mL) are common and may indicate iron deficiency anemia, which can impair performance. Studies show that iron supplementation in confirmed deficiency improves endurance capacity. However, ferritin is an acute-phase reactant; inflammation or infection can falsely elevate or lower values. A single ferritin test is insufficient for diagnosis – it should be combined with hemoglobin, transferrin saturation, and CRP. Consumer DNA tests do not measure ferritin directly; they only report genetic variants (e.g., HFE) that may increase risk of iron overload. The evidence for routine ferritin screening in athletes is moderate (observational studies, some RCTs). Caution: unsupervised iron supplementation can be harmful in cases of iron overload (e.g., hemochromatosis).