What role does FUT2 play in Müdigkeit?

FUT2 (fucosyltransferase 2) determines secretor status and influences gut microbiome composition and vitamin B12 absorption. A non-functional FUT2 allele ('non-secretor') can reduce B12 uptake, potentially contributing to fatigue in susceptible individuals. However, the effect is indirect and modulated by diet, gut health, and lifestyle. MyBody-X typically does not include FUT2; even if it did, the predictive value for fatigue would be low. B12 deficiency should be assessed via blood test. The evidence linking FUT2 directly to fatigue is mechanistic, not clinically validated.