Vitamin B12 deficiency causes

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Vitamin B12 deficiency Microchapters


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Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1] Associate Editor(s)-in-Chief: Luke Rusowicz-Orazem, B.S.


Common causes of vitamin B12 deficiency include insufficient dietary intake, as well as diseases and iatrogenic procedures causing problems in absorption. It is common in individuals adhering to vegetarian or vegan diets without external supplementation, due to primary sources including animal products such as meat, eggs, and dairy.


Common Causes

Causes by Organ System

Cardiovascular No underlying causes
Chemical/Poisoning Nitroux oxide abuse
Dental No underlying causes
Dermatologic No underlying causes
Drug Side Effect Cimetidine, Glyburide , Metformin hydrochloride, Neomycin, Omeprazole, Pantoprazole, Prolonged antiacid use, Rabeprazole, Ranitidine hydrochloride, Saxagliptin hydrochloride
Ear Nose Throat No underlying causes
Endocrine Graves' disease
Environmental No underlying causes
Gastroenterologic Achlorhydria, Atrophic gastritis, Bariatric surgery, Blind loop syndrome, Bothriocephalosis, Celiac disease, Chronic pancreatitis, Cobalamin malabsorption, Crohn's disease, Gastrectomy, Gastritis, Grasbeck-imerslund disease, Ileal resection, Imerslund-najman-grasbeck anemia, Malabsorption syndrome, Pancreatic insufficiency, Pancreatitis, Postgastrectomy syndrome, Small bowel disease
Genetic Homocystinuria, Mthfr deficiency
Hematologic Grasbeck-imerslund disease, Imerslund-najman-grasbeck anemia, Intrinsic factor deficiency , Juvenile megaloblastic anemia, Macrocytic anemia, Megaloblastic anemia, Pernicious anemia, Transcobalamin deficiency
Iatrogenic Bariatric surgery, Gastrectomy, Ileal resection, N2o anesthesia , Postgastrectomy syndrome
Infectious Disease Bothriocephalosis, Diphyllobothrium latum
Musculoskeletal/Orthopedic No underlying causes
Neurologic No underlying causes
Nutritional/Metabolic Cobalamin malabsorption, Excessive alcohol consumption, Insufficient diet, Veganism, Vegetarianism
Obstetric/Gynecologic No underlying causes
Oncologic No underlying causes
Ophthalmologic No underlying causes
Overdose/Toxicity Excessive alcohol consumption, Nitroux oxide abuse
Psychiatric No underlying causes
Pulmonary No underlying causes
Renal/Electrolyte No underlying causes
Rheumatology/Immunology/Allergy Crohn's disease, Systemic lupus erythematosus
Sexual No underlying causes
Trauma No underlying causes
Urologic No underlying causes
Miscellaneous Idiopathic

Cause in Alphabetical Order


  1. Camarero-Shelly M, Pellitero S, Martínez E, Puig R, Leis A, Zavala R, Granada ML, Pastor C, Moreno P, Tarascó J, Balibrea J, Puig-Domingo M (April 2018). "[Vitamin B12 levels in the patient population attending an urban health centre in Madrid]". Semergen (in Spanish; Castilian). 44 (3): 161–167. doi:10.1016/j.semerg.2017.03.006. PMID 28457771.
  2. Gomollón F, Gargallo CJ, Muñoz JF, Vicente R, Lue A, Mir A, García-Alvarado M, Gracia M, García-López S (March 2017). "Oral Cyanocobalamin is Effective in the Treatment of Vitamin B12 Deficiency in Crohn's Disease". Nutrients. 9 (3). doi:10.3390/nu9030308. PMC 5372971. PMID 28335526.
  3. Orskov I, Orskov F (January 1966). "Episome-carried surface antigen K88 of Escherichia coli. I. Transmission of the determinant of the K88 antigen and influence on the transfer of chromosomal markers". J. Bacteriol. 91 (1): 69–75. PMID 5323299.
  4. de Jager J, Kooy A, Lehert P, Wulffelé MG, van der Kolk J, Bets D, Verburg J, Donker AJ, Stehouwer CD (May 2010). "Long term treatment with metformin in patients with type 2 diabetes and risk of vitamin B-12 deficiency: randomised placebo controlled trial". BMJ. 340: c2181. PMC 2874129. PMID 20488910.

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