What role does FUT2 play in Darmgesundheit?

FUT2 (fucosyltransferase 2) encodes an enzyme that controls the expression of H antigens on the gut mucosa and in bodily secretions. The so-called secretor status (active vs. inactive) is determined by common FUT2 variants (e.g., rs601338). Non-secretors show an increased risk for Crohn's disease, an altered gut microbiome (fewer Bifidobacteria), and reduced susceptibility to norovirus infection. Additionally, FUT2 influences vitamin B12 absorption because intrinsic factor binds to H antigens. Evidence comes from GWAS associations and microbiome studies, but the effects are moderate and modifiable by diet and other genes. A standalone FUT2 genetic test without clinical context is not sufficient for meaningful gut health assessment.