Vitamin B12 is required for a number of metabolic processes. Which of the following lesions would NOT lead to a deficiency of this vitamin?
Absorption of vitamin B12 requires formation of a complex with intrinsic factor, which is secreted by parietal cells of the stomach. Destruction of these cells thus results in a vitamin B12 deficiency. The vitamin B12-intrinsic factor complex is absorbed in the ileum. Thus, surgical resection of the ileum, but not of the jejunum, will also produce a deficiency. Ref: Kaushansky K., Kipps T.J. (2011). Chapter 37. Hematopoietic Agents: Growth Factors, Minerals, and Vitamins. In L.L. Brunton, B.A. Chabner, B.C. Knollmann (Eds), Goodman & Gilman's The Pharmacological Basis of Therapeutics, 12e.
Chronic gastritis resulting in achlorhydria
Autoimmune destruction of gastric parietal cells
Surgical resection of the jejunum
Surgical resection of the ileum