Vitamin B12 is essential for red blood cell production, DNA synthesis and cellular and tissue repair. The body does not create B12, and people must consume foods high in vitamin B12 to avoid a deficiency. Symptoms of a deficiency include diarrhea, fatigue, loss of appetite, shortness of breath and confusion. When the body lacks enough of a special protein called intrinsic factor, vitamin B12 absorption is impaired, leading to a decrease in red blood cells. This condition is called pernicious anemia.
Intrinsic Factor and Absorption
Intrinsic factor is created by the parietal cells within the stomach. It is a necessary part of the body's B12 processing because it binds with B12 in the stomach to prepare the vitamin for absorption by the small intestine.
Causes
In some cases, pernicious anemia is triggered by an autoimmune disorder, in which the body's immune system begins attacking its own cells. In autoimmune pernicious anemia, the body attacks the gastric parietal cells that create intrinsic factor. Another potential cause of pernicious anemia is atrophic gastritis, a chronic inflammation of the stomach lining that affects the parietal cells and the creation of intrinsic factor.
Risk Factors
People with a history of autoimmune endocrine disorders such as Type 1 diabetes or testicular dysfunction are at increased risk for pernicious anemia, as are people with low pituitary, parathyroid, adrenal gland or thyroid function.
Treatments
Because a lack of intrinsic factor prevents absorption of B12 through the intestines, treatment involves finding other ways to deliver B12 to the body. Patients may require take lifelong or long-term B12 injections to correct the deficiency, although one form of B12 can be taken through the nose. Elderly patients suffering from gastric atrophy may take B12 supplements orally as well as receive injections monthly.
Considerations
Patients treated within six months of B12 deficiency often recover without any long-term effects. However, people with pernicious anemia do have an increased risk of gastrointestinal problems such as gastric cancer, polyps and carcinoid tumors.
Member Comments