Pernicious anemia is a medical problem that causes a person to have too few red blood cells (anemia) because their intestines cannot absorb vitamin B12 properly. 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.