Anemia of B12 deficiency

Definition:

Anemia of B12 deficiency is a decrease in the red cells in the blood caused by a vitamin deficiency.

Causes, incidence, and risk factors:

Vitamin B12 is essential for normal nervous system function and normal red cell, white cell and platelet production. All sources of vitamin B12 come from the diet in animal products, including dairy and eggs. For vitamin B12 to be absorbed by the body, it must become bound to an intrinsic factor, a protein secreted by cells in the stomach. Causes of vitamin B12 deficiency include dietary (a strict vegetarian diet excluding all meat, fish, dairy products, and eggs); chronic alcoholism; abdominal or intestinal surgery that eliminates the site of intrinsic factor production or absorption; Crohn's disease; intestinal malabsorption disorders; fish tape worm; and pernicious anemia, which is caused by an inherited intrinsic factor deficiency. Risk factors are related to the causes. The incidence is 2 out of 1000 people.