Pernicious anemia
A special protein, called intrinsic factor, helps the body get vitamin B12 from food such as meat, poultry and dairy foods. Intrinsic factor is made by cells in the stomach. If there is not enough intrinsic factor, the small intestine is unable to get the vitamin B12. There are several causes of pernicious anemia. These include a weakened stomach lining or a problem with the body's immune system which causes it to attack the intrinsic factor. In some rare cases is can be passed down through families. Treatment is usually a regular injection of vitamin B12.