Causes of Low Vitamin B12 Levels Low vitamin B12 intake - Vegetarianism, chronic alcoholism and older people Autoimmune - Pernicious anaemia and Sjögren's syndrome Food-bound cobalamin malabsorption - Atrophic gastritis, chronic gastritis and Helicobacter pylori-associated gastritis Surgery - Post-gastrectomy and ileal resection Malabsorption - Small intestinal bacterial overgrowth, chronic pancreatic exocrine insufficiency, Crohn 's disease, coeliac disease and achlorhydria Obstetric/gynaecological - Oral contraceptive, hormone replacement therapy and pregnancy Genetic - Transcobalamin II deficiency Drugs - Metformin, proton pump inhibitors and histamine H2-receptor antagonists #VitaminB12 #deficiency #low #cobalamin #differential #diagnosis
