Is Ferritin useful for blood sugar?

Ferritin is a storage protein for iron and is commonly used as a marker of body iron stores. Its relevance to blood sugar is indirect: elevated ferritin levels (iron overload) have been associated in observational studies with increased insulin resistance and a higher risk of type 2 diabetes. However, ferritin is also an acute-phase reactant, meaning it rises with inflammation, which itself can impair glucose metabolism. Conversely, low ferritin (iron deficiency) may worsen glucose tolerance because iron is needed for insulin secretion and action. The evidence is moderate: no randomized controlled trials directly demonstrate that adjusting ferritin improves blood sugar control. Ferritin should not replace established glycemic markers like HbA1c or fasting glucose. Clinically, abnormal ferritin warrants further investigation for conditions such as hemochromatosis or iron deficiency anemia. In summary, ferritin can serve as a risk marker but is not a standalone tool for blood sugar assessment.