Evidence check: FUT2 in the context of Schlaf

Evidence for a direct link between the FUT2 gene (fucosyltransferase 2) and sleep is weak. FUT2 determines secretor status and influences gut microbiome composition and vitamin B12 absorption. An indirect effect on sleep via the gut-brain axis or B12 deficiency is plausible, but no robust human studies associate FUT2 variants with sleep quality, duration, or disorders. Existing literature (e.g., on B12 and sleep) is mostly mechanistic or observational. Therefore, a FUT2 genetic test does not provide actionable sleep insights. For sleep issues, focus on established factors: sleep hygiene, stress, diet, and medical causes (e.g., sleep apnea). A microbiome test may offer complementary clues but does not replace clinical evaluation. Evidence: unclear – no direct studies in the provided context.