Myths vs facts: Transferrin and longevity

Transferrin is an iron-transport protein, and its blood levels are commonly used as a marker of iron status. A myth suggests that high transferrin levels directly predict longevity. In reality, the evidence is nuanced: iron overload (hemochromatosis) can cause oxidative stress and organ damage, shortening lifespan, while iron deficiency is also harmful. Transferrin itself is not a direct longevity marker but part of a regulatory system. Studies in model organisms show that moderate iron restriction can extend lifespan, but human translation is unclear. Some observational studies link low transferrin saturation to increased mortality, but causal conclusions are not warranted. In summary, transferrin values are clinically relevant but insufficient as a standalone predictor of longevity. The evidence is primarily mechanistic and based on associative studies.