How does pernicious anemia develop?
Pernicious anemia results from the failure of the digestive tract to absorb vitamin B12. This is due to insufficient amounts of the protein called intrinsic factor, which is secreted by parietal cells that line part of the stomach. Normally, after being ingested, B12 binds with intrinsic factor to be absorbed into the blood stream. Without intrinsic factor, vitamin B12 remains in the intestine and is excreted into the stool. In pernicious anemia, the immune system produces autoantibodies that inhibit the parietal cells from secreting intrinsic factor. As a result, vitamin B12 isn’t absorbed and anemia develops even if large amounts of the vitamin, or food containing the vitamin, are consumed. Some other possible causes of this condition include a bacterial growth in the small intestine, which would prevent vitamin B12 absorption, Crohn’s disease or the surgical removal of portions of the stomach and small intestine where the parietal cells reside. What are the symptoms of pernicious an
