What effect does a lack of intrinsic factor have on Red blood cells?

A lack of intrinsic factor, a protein produced by the stomach, leads to impaired absorption of vitamin B12, which is essential for red blood cell production. This deficiency can result in megaloblastic anemia, characterized by the production of large, immature red blood cells that are ineffective in transporting oxygen. Consequently, individuals may experience fatigue, weakness, and pallor due to reduced oxygen-carrying capacity. Additionally, a lack of intrinsic factor can be a sign of pernicious anemia, an autoimmune condition affecting the stomach lining.