Myths vs facts: B12 and gut health

The provided context does not contain specific information on vitamin B12 and gut health. B12 deficiency can result from inadequate intake, gastrointestinal disorders, or impaired absorption (e.g., atrophic gastritis, celiac disease, Crohn's disease). A home B12 test may indicate deficiency but does not replace clinical evaluation. The gut microbiota does not produce B12; absorption occurs in the terminal ileum and depends on intrinsic factor. Without supporting evidence, direct conclusions from a microbiome test about B12 status are not valid. If deficiency is suspected, a doctor should measure markers like holotranscobalamin and methylmalonic acid.