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Megaloblastic anemia - view of red blood cells
Megaloblastic anemia - view of red blood cells


Anemia - B12 deficiency

Definition:

Anemia is a drop in the number of red blood cells. This can be caused by a lack of vitamin B12.



Alternative Names:
Macrocytic anemia

Causes, incidence, and risk factors:

Vitamin B12 is essential for normal nervous system function and blood cell production. The main sources of vitamin B12 include meat, eggs, and dairy products. For vitamin B12 to be absorbed by the body, it must bind to intrinsic factor, a protein secreted by cells in the stomach.

Causes of vitamin B12 deficiency include:

  • A diet low in vitamin B12 (for example, a strict vegetarian diet that excludes all meat, fish, dairy products, and eggs)
  • Chronic alcoholism
  • Abdominal or intestinal surgery that affects intrinsic factor production or absorption
  • Crohn's disease
  • Intestinal malabsorption disorders
  • Fish tape worm
  • Pernicious anemia, which is caused by a lack of intrinsic factor

The risk factors are related to the causes.




Review Date: 1/26/2005
Reviewed By: Rita Nanda, MD., Department of Hematology/Oncology, University of Chicago Medical Center, Chicago, IL. Review provided by VeriMed Healthcare Network.

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