What is the primary function of intrinsic factor produced by parietal cells?

The primary function of intrinsic factor, which is produced by parietal cells in the stomach, is to facilitate the absorption of vitamin B12. This vitamin is crucial for several bodily functions, particularly in the production of red blood cells and maintaining the health of nerve cells. Vitamin B12 absorption occurs primarily in the ileum of the small intestine; however, it requires intrinsic factor to be present in order for the vitamin to be absorbed effectively.

Without sufficient intrinsic factor, vitamin B12 cannot be adequately absorbed, leading to conditions such as pernicious anemia. This highlights the importance of intrinsic factor in ensuring that the body receives enough of this vital nutrient.

The other options relate to different processes or substances, such as digestion of proteins, absorption of calcium, and regulation of stomach acidity, which do not encompass the specific role of intrinsic factor in vitamin B12 absorption.