Question

What is the role of lack of intrinsic factor in the stomach secretions in relation to the absorption of Vitamin B12?

1) It prevents the absorption of Vitamin B12
2) It enhances the absorption of Vitamin B12
3) It has no effect on the absorption of Vitamin B12
4) It causes the breakdown of Vitamin B12

Answer 1

Lack of intrinsic factor in the stomach prevents the absorption of Vitamin B12, essential for red blood cell production and neurological function, leading to pernicious anemia.

Step-by-step explanation:

The lack of intrinsic factor in the stomach secretions prevents the absorption of Vitamin B12. Intrinsic factor is a glycoprotein secreted by the gastric glands that is essential for the absorption of Vitamin B12 in the small intestine. Without intrinsic factor, Vitamin B12 cannot bind to mucosal receptors in the terminal ileum, a key step in the vitamin's absorption process, leading to a condition known as pernicious anemia. People who lack intrinsic factor or undergo a total gastrectomy can survive if they receive Vitamin B12 injections, bypassing the need for intrinsic factor.