Ferritin
The iron reserve — and an underrated inflammatory marker
Definition
Ferritin is the intracellular protein that stores iron in a non-toxic, bioavailable form. Its serum level reflects total body iron stores: low in iron deficiency, high in iron overload (hemochromatosis, hemolysis, transfusions). But ferritin is also an acute-phase protein — it rises with systemic inflammation, so elevated levels without iron overload indicate inflammaging or underlying chronic disease. It is one of the biomarkers with the most nuanced interpretation in longevity medicine.
Detailed explanation
Clinical reference vs. longevity-optimal values:
Premenopausal women: clinical 15-150 ng/mL; optimal 30-100 ng/mL Men and postmenopausal women: clinical 30-400 ng/mL; optimal 50-150 ng/mL >200 ng/mL without overload: investigate inflammation, MAFLD (fatty liver), metabolic syndrome >300 ng/mL: investigate hemochromatosis (TSAT >45%) or inflammatory cause <30 ng/mL: functional iron deficiency even with normal hemoglobin
High ferritin as an inflammatory sign is associated with higher risk of type 2 diabetes, MAFLD, stroke, heart attack, and all-cause mortality. Regular blood donation in men and postmenopausal women with elevated ferritin is a simple, free, and effective intervention to reduce stored iron and improve inflammatory markers.
Complementary evaluation: transferrin saturation (TSAT), total iron-binding capacity (TIBC), soluble transferrin receptor (sTfR — not affected by inflammation), hepcidin (master regulator of iron metabolism). Correct interpretation requires looking at the whole picture, not just the isolated ferritin value.
Scientific sources
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