Which of the following vitamins is absorbed in the ileum?

Vitamin B12 is absorbed in the ileum, which is the final section of the small intestine. The absorption of vitamin B12 is a complex process that requires the presence of intrinsic factor, a protein produced in the stomach. This vitamin is crucial for the production of red blood cells and the maintenance of the nervous system. Its absorption specifically occurs in this segment of the intestine after it has been released from food in the stomach and bound to intrinsic factor.

Understanding the absorption locations of various vitamins can be important in clinical practice, especially when considering conditions that affect specific parts of the gastrointestinal tract. For instance, patients with ileal resections or diseases affecting the ileum may have difficulty absorbing vitamin B12, leading to deficiencies.

Other vitamins listed, such as vitamin C and vitamin E, are absorbed in different sections of the intestines. Vitamin K is primarily absorbed in the jejunum, which is situated between the duodenum and the ileum. Thus, the specificity of vitamin B12 absorption in the ileum sets it apart and confirms the correctness of the answer.