Is Transferrin useful for gut health?

Transferrin is an iron-transport protein and primarily a marker of iron status, not directly of gut health. However, iron imbalance can affect the gut microbiome—both excess and deficiency disrupt microbial balance. The clinical utility of measuring transferrin alone for gut health is low and not evidence-based. In practice, transferrin is used to assess iron deficiency or overload (e.g., hemochromatosis). Direct-to-consumer tests marketing transferrin as a 'gut health marker' often overstate the evidence. A more comprehensive approach including iron parameters, inflammatory markers, and stool analysis is warranted. Evidence: mechanistic/insufficient.