Evidence check: FUT2 in the context of Stress

The FUT2 variant (secretor status) influences gut microbiome composition and vitamin B12 absorption. Some studies suggest links to systemic inflammation and possibly stress responses, as the gut microbiome interacts with the stress hormone system via the gut-brain axis. However, evidence for a direct FUT2–stress connection is weak and primarily mechanistic. Effect sizes are small, and lifestyle factors (diet, sleep, exercise) dominate. MyBody-X provides genotype but not functional measurement. Clinical decisions should not rely on this marker alone. Beware of exaggerated marketing claims.