Which vitamin is solely absorbed in the ileum?

Vitamin B12 is the only vitamin that is absorbed exclusively in the ileum, which is the final segment of the small intestine. This vitamin plays a critical role in the production of red blood cells and the maintenance of the central nervous system. Its absorption process is complex; Vitamin B12 must first bind to intrinsic factor, a protein produced in the stomach, to be safely absorbed in the ileum.

While other vitamins are absorbed in various parts of the gastrointestinal tract, none are restricted to the ileum like Vitamin B12. For instance, Vitamin A is primarily absorbed in the proximal small intestine, Vitamin C is absorbed throughout the small intestine, and Vitamin D absorption occurs in the distal small intestine. This specificity to the ileum highlights the importance of intrinsic factor and the health of this segment of the digestive system for adequate Vitamin B12 absorption, making it essential for preventing deficiencies that can lead to pernicious anemia and neurological issues.