Causes of Vitamin B12 Deficiency
Vitamin B12 deficiency has three primary underlying causes:
Pernicious anemia is a form of autoimmune disorder characterized by the production of antibodies against intrinsic factor. Antibodies against intrinsic factor tend to bind and inhibit the intrinsic factor’s normal activity. Vitamin B12 cannot be absorbed by the ileum as a consequence.
Nutritional deficiencies: Our body accumulates excess vitamin B12 in the liver, but patients following a strict vegan diet for nearly three years may develop vitamin B12 deficiency due to a lack of adequate dietary intake.
Malabsorptive disorder: As intrinsic factor is produced by parietal cells lining the stomach, any patient with a history of gastric surgery may be at risk for vitamin B12 deficiency. As the new alimentary pathway bypasses the site of intrinsic factor production, vitamin B12 absorption in the small intestine may be compromised. Any injury to the small intestine, including inflammation caused by celiac disease or tapeworm infection, may also result in a vitamin B12 deficiency. Damage to the terminal portion of the ileum, such as in Crohn’s disease-related surgical resection, can cause vitamin B12 malabsorption in individuals with normal intrinsic factor production.
Included among those at risk for vitamin B12 deficiency are:
Patients taking diabetic medications such as metformin
Individuals who are strict vegetarians
The elderly who use antacids for an extended duration
Patients undergoing colon removal surgery
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