Myths vs facts: Ferritin Eisenmangel and Blutzucker

Several myths surround ferritin, iron deficiency, and blood sugar. Fact: Ferritin is an iron storage protein but also an acute-phase reactant – elevated levels can result from inflammation (e.g., infection, obesity), not necessarily iron overload. A common myth is that low ferritin directly causes high blood sugar. Evidence shows that iron deficiency can impair insulin secretion and action, but the association is moderate and not clearly causal. Another myth: High ferritin is always dangerous. In reality, ferritin rises in metabolic syndrome and fatty liver without hemochromatosis. Ferritin alone is insufficient; transferrin saturation and CRP are needed. For iron deficiency, the underlying cause (e.g., blood loss, malabsorption) must be investigated before supplementation. Caveat: Self-tests without clinical interpretation can mislead. The evidence base is human-moderate, with many observational studies but few RCTs directly linking ferritin to blood glucose changes.