How are FUT2 and Schlaf related?

The link between FUT2 and sleep is indirect and not well-established in current evidence. FUT2 determines secretor status and influences gut microbiota composition, particularly Bifidobacteria levels. Through the gut-brain axis, gut microbes can modulate neurotransmitter production (e.g., serotonin, melatonin) that affect sleep-wake cycles. Some observational studies suggest associations between microbiota diversity and sleep quality, but direct evidence linking specific FUT2 variants to sleep outcomes is lacking. The effects are small and confounded by diet, stress, and lifestyle. A single FUT2 variant alone does not predict sleep health. Consumer DNA tests often overstate such connections. Evidence: mechanistic, based on indirect associations. Sources: none directly in the provided context.