Causes

The six most commonly identified causes of B12 deficiency are…

• An inability to absorb B12 from food. Please note, vitamin B12 is only found naturally in animal products.
• A diet deficient in B12- for example, following a vegan or vegetarian diet.
• Autoimmune pernicious anaemia.
• A genetic defect (including MTHFR, MTRR)
• Medications that hinder the body’s ability to use B12- for example metformin and acid suppressants. 
• A secondary deficiency in a child, stemming from the mother being vitamin B12 deficient either prior to conception, during pregnancy or during nursing.

Below is a comprehensive list of potential causes of vitamin B12 deficiency…

• Toxic exposure
• Decreased stomach acid
• Atrophic gastritis
• Autoimmune pernicious anaemia
• Helicobacter pylori
• Gastrectomy, partial or complete
• Gastric bypass surgery (weight loss)
• Intestinal resection
• Partial or complete ileectomy
• Gastrointestinal neoplasms
• Malnutrition
• Eating disorders  – anorexia – bulimia
• Inadequate diet
• Vegetarianism / veganism
• Malabsorption syndromes
• Alcoholism
• Crohn’s disease
• Coeliac disease (gluten enteropathy)
• Diphyllobothrium infection
• Blind loop syndrome
• Diverticulosis
• Inflammatory bowel disease
• Small bowel overgrowth (SIBO)
• Tropical sprue
• Gastric irradiation
• Ileal irradiation (bladder, cervix, uterus, prostate)
• Inborn errors of B12 metabolism
• Transcobalamin II deficiency
• Pancreatic exocrine insufficiency & Chronic pancreatitis
• Imerslund Gräesbeck syndrome
• Zollinger – Ellison Syndrome
• Bacterial overgrowth (small bowel)
• Fish tapeworm
• Advanced liver disease

Medicine / Drug induced causes – Please note this list is not exhaustive…

• Antacids
• Colchicine – treatment of gout
• H2 Blockers (Zantac, Tagamet, Pepcid)
• Metformin – diabetes drug (Glucophage)
• PPI’s – Proton pump inhibitors (Omeprazole, Nexium, Prevacid, Protonix)
• Nitrous oxide anaesthetic
• Nitrous oxide recreational abuse (laughing gas / whippets / hippy crack)
• Levodopa – treatment of Parkinson’s
• Mycifradin sulphate (Neomycin) – antibiotic
• Para aminosalicylates – antibiotic
• Phenytoin (Dilantin), Gabapentin – anti-epileptic
• Potassium chloride (K-Dur)
• Cholestyramine (Questran)
• Chemotherapy and radiation treatment

Conditions which have an increased demand for B12…

• Chronic haemoltic anaemia
• Hyperthyroidism
• Multiple myeloma
• Myeloproliferative disorders
• Neoplasms
• Pregnancy

Personalised help…
If you would like personalised help either with reaching a diagnosis, or with receiving proper, effective treatment from your healthcare providers post-diagnosis, please see the Work with me page.

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