digestion: absorption

Question

Vitamin B12 absorption in ileum requires which glycoprotein?

RankGuru · Accepted Answer

1. **Vitamin $B_{12}$ (Cyanocobalamin)**: Essential for RBC formation; absorption is complex.
2. **Stomach Phase**: Parietal cells of the stomach secrete a glycoprotein called **Intrinsic Factor (IF)**.
3. **Binding**: Intrinsic factor binds to Vitamin $B_{12}$ in the small intestine, protecting it from digestion.
4. **Ileal Phase**: The $IF-B_{12}$ complex is recognized by specific receptors in the **terminal ileum** (the last part of the small intestine), where absorption occurs.
5. **Deficiency**: Lack of Intrinsic Factor leads to Vitamin $B_{12}$ deficiency and Pernicious Anemia.

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digestion: absorption

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