What are the causes?

There are many causes for B12 deficiency. Autoimmune pernicious anaemia is just one. However having one autoimmune condition can unfortunately predispose some to develop others. For example many people who are coeliac or have thyroid dysfunction are also B12 deficient. Many common drugs can cause B12 deficiency as can some surgery and parasites, please see below.

(Please note that folate deficiency which often accompanies B12 deficiency, can be caused by many commonly prescribed drugs too).

We have developed an app to help determine your risk of B12 deficiency.

The What to do Next page is a good place to start if you think you may be deficient. If you need personalised help please see the contact page for more information.

You can view a 90 minute broadcast on B12 deficiency with me, from the Academy of Physical Medicine here. There is a small charge. See a clip here

Very Important: DO NOT SUPPLEMENT BEFORE TESTING - THIS MAY SKEW RESULTS.

The six most commonly identified causes of B12 deficiency are;

• An inability to absorb B12

• A diet deficient in B12

• An autoimmune disorder

• A genetic defect (including MTHFR, MTRR)

• Medications that hinder the body's ability to use B12

• A secondary deficiency in a child, stemming from maternal deficiency prior to conception, during pregnancy or during nursing.

Toxic exposure could also be a factor please also see the Antidote page

More below;

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
illeal 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

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 anaesthesia
Nitrous oxide recreational abuse (Laughing gas / Whippets / Hippy crack)
Levodopa (treatment of Parkinson's)
Mycifradin sulphate (Neomycin) antibiotic
Para aminosalicylates antibiotic
Phenytoin (Dilantin) - anti-epileptic
Potassium chloride (K-Dur)
Cholestyramine (Questran)
Chemotherapy and radiation treatment

Increased demands

Chronic Hemoltic anaemia
Hyperthyroidism
Multiple myeloma
Myeloproliferative disorders
Neoplasms
Pregnancy

Information provided with kind permission of Sally M. Pacholok R.N. & Dr. Jeffrey J. Stuart.

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What are the causes?

Drug induced causes - Please note; this list is not exhaustive

Increased demands

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