Which factor is essential for absorption of vitamin B12?
Which factor is essential for absorption of vitamin B12?
Intrinsic factor
Intrinsic factor is a protein that helps your intestines absorb vitamin B12. It is made by cells in the stomach lining.
What is the intrinsic factor in B12 absorption?
Intrinsic factor is a glycoprotein produced by parietal cells in the stomach and necessary for the absorption of vitamin B12 in the terminal ileum. Once absorbed, vitamin B12 is used as a cofactor for enzymes that are involved in the synthesis of deoxyribonucleic acid (DNA), fatty acids, and myelin.
What stimulates intrinsic factor?
Intrinsic factor is produced by the gastric parietal cell. Its secretion is stimulated via all pathways known to stimulate gastric acid secretion: histamine, gastrin, and acetylcholine.
What affects intrinsic factor?
Disease at a Glance Intrinsic factor deficiency is caused by changes in the GIF gene and is inherited in an autosomal recessive manner.
What causes a vitamin B12 deficiency?
Some people can develop a vitamin B12 deficiency as a result of not getting enough vitamin B12 from their diet. A diet that includes meat, fish and dairy products usually provides enough vitamin B12, but people who do not regularly eat these foods can become deficient.
Which cell is responsible for absorption of vitamin B12?
Intrinsic factor is a glycoprotein secreted by parietal (humans) or chief (rodents) cells of the gastric mucosa. In humans, it has an important role in the absorption of vitamin B12 (cobalamin) in the intestine, and failure to produce or utilize intrinsic factor results in the condition pernicious anemia.
What destroys intrinsic factor?
In an autoimmune disease such as pernicious anemia, the body’s immune system stops distinguishing between diseased and healthy tissue. In this case, autoantibodies destroy the stomachs cells that make intrinsic factor and impede its function.
What causes lack of intrinsic factor?
The inability to make intrinsic factor may be the result of several factors, such as chronic gastritis, gastrectomy (removal of all or part of the stomach), or an autoimmune condition (the body attacks its own tissues).
Can intrinsic factor be restored?
Pernicious anaemia in the adult can be defined as a megaloblastic anaemia associated with avitaminosis B12, due to defective absorption of the vitamin, which absorption can be restored to normal by the administration of intrinsic factor. This defect is associated with an irreversible degeneration of the gastric mucosa.
