Myths vs facts: FUT2 and weight loss

FUT2 (fucosyltransferase 2) determines secretor status and influences gut microbiome composition and vitamin B12 absorption. Some consumer tests claim that certain FUT2 variants are linked to weight loss. However, the scientific evidence is weak. There are GWAS associations with BMI, but effect sizes are tiny and not clinically relevant. A direct link to weight loss is not established. Fact: FUT2 affects B12 status and gut flora – both can indirectly influence metabolism, but not directly cause weight loss. Myth: A FUT2 test cannot predict whether someone will lose weight easily. Weight loss is polygenic and heavily driven by lifestyle, diet, and exercise. Beware of overblown claims: single SNPs like FUT2 are not weight-loss determinants. Evidence: human-moderate for B12/microbiome, but mixed for weight loss. Sources: no specific PMIDs in context.