Which vitamin deficiency is associated with pernicious anemia after gastrectomy?

Pernicious anemia is primarily caused by a deficiency of vitamin B12, which is essential for the production of red blood cells. After gastrectomy, which involves the surgical removal of part or all of the stomach, patients can develop a deficiency in intrinsic factor. Intrinsic factor is a protein produced by the stomach that is critical for the absorption of vitamin B12 in the intestine. Without adequate intrinsic factor, even if dietary vitamin B12 is consumed, it cannot be effectively absorbed, leading to a deficiency.

In the context of gastrectomy, the loss of stomach tissue results in decreased production of intrinsic factor, thus making it difficult for the body to utilize vitamin B12. This leads to impaired DNA synthesis in red blood cell production, ultimately resulting in the characteristic megaloblastic anemia seen in pernicious anemia. Therefore, vitamin B12 deficiency is directly linked to the condition following a gastrectomy operation.

Other vitamin deficiencies do not have the same direct association with pernicious anemia following stomach surgery, emphasizing the specific role of vitamin B12 in this condition.