Vitamin B12 helps in red blood cell formation, production of DNA, and function of the nervous system.

Vitamin B12 deficiency can occur when the body needs more vitamin B12 than it receives from the diet. Alternatively, the condition may occur when the body is unable to use the vitamin B12 from the diet. A shortage of vitamin B12 can lead to anemia. Anemia occurs when levels of red blood cells are abnormally low and there is insufficient delivery of oxygen by red blood cells from the lungs to the cells of the body.

Red Blood Cells
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There are many causes of vitamin B12 deficiency. Some are listed below.

  • Removal of part of the small intestine or stomach
  • Increased age and inadequate absorption of B12
  • Long-term use of certain acid-reducing stomach medications:
    • H2 blockers
    • Proton pump inhibitors
  • Atrophic gastritis (inflammation of the stomach) due to:
  • Disorders affecting vitamin absorption:
  • Inadequate intake of vitamin B12
    • Long-term veganism (nonconsumption of animal products) or vegetarianism
    • Breastfed infants of vegan or vegetarian mothers
    • Poor nutrition
    • Inadequate nutrition for a pregnant woman
    • Chronic alcohol abuse
  • Chronic intestinal conditions that lead to malabsorption
  • Inflammation of the intestine due to radiation treatment
  • Malnutrition
  • Increased need of vitamin B12:
  • Metabolic disorders: