After Randy was diagnosed with stomach cancer, nearly all of his stomach had to be removed. Postoperative treatment included regular injections of vitamin B12. Why was this vitamin prescribed, and why were injections specified?

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Understand the role of vitamin B12 in the body: Vitamin B12 is essential for red blood cell formation, neurological function, and DNA synthesis.

Recognize that vitamin B12 absorption requires intrinsic factor, a protein secreted by parietal cells in the stomach lining, which binds to vitamin B12 and allows its absorption in the ileum.

Since Randy had nearly all of his stomach removed, the intrinsic factor production is severely reduced or absent, impairing the normal absorption of vitamin B12 from the diet.

Because oral vitamin B12 cannot be effectively absorbed without intrinsic factor, vitamin B12 injections are prescribed to bypass the gastrointestinal tract and deliver the vitamin directly into the bloodstream.

Therefore, the injections ensure that Randy receives adequate vitamin B12 to prevent deficiency-related complications such as pernicious anemia and neurological problems.

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Key Concepts

Here are the essential concepts you must grasp in order to answer the question correctly.

Role of Vitamin B12 in the Body

Vitamin B12 is essential for red blood cell formation, DNA synthesis, and neurological function. It is primarily absorbed in the ileum after binding to intrinsic factor, a protein produced by stomach cells. Deficiency can lead to anemia and neurological issues.

Intrinsic Factor and Vitamin B12 Absorption

Intrinsic factor is a glycoprotein secreted by parietal cells in the stomach lining, necessary for vitamin B12 absorption in the small intestine. Removal of most of the stomach reduces intrinsic factor production, impairing B12 absorption and causing deficiency.

Rationale for Vitamin B12 Injections Post-Gastrectomy

After stomach removal, oral vitamin B12 cannot be absorbed effectively due to lack of intrinsic factor. Therefore, vitamin B12 is administered via injections to bypass the gastrointestinal tract, ensuring adequate levels and preventing deficiency-related complications.

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