How are MTHFR and Darmgesundheit related?

The link between MTHFR variants and gut health is frequently mentioned in popular health contexts, but the scientific evidence is limited. MTHFR is a key enzyme in folate metabolism and methylation. Impaired methylation could theoretically affect gut barrier integrity and microbiome composition via altered neurotransmitter synthesis or inflammatory responses. However, most evidence comes from mechanistic reasoning and animal models; robust human studies are scarce. The MyBody-X DNA test cannot diagnose folate deficiency or gut disorders. The effect sizes of common MTHFR polymorphisms on gut health are small and easily overshadowed by diet, lifestyle, and medications. For actual gut symptoms or suspected deficiencies, blood and stool tests are essential. Supplementation with active folate or other B vitamins should only be considered after proper lab confirmation. Evidence: mechanistic/unclear.