ABSTRACT
The complexity of the digestive process means that abnormalities can occur at several points. An inability to effectively degrade proteins in food, such as that occurring in achlorhydria or atrophic gastritis, often prevents release of vitamin B12 from food. Transfer of vitamin B12 from food to Hc, which is dependent on pH and pepsin secretion, may also be compromised. Finally, lack of IF, due to the autoimmune condition PA, will prevent the uptake of Cbl by the ileal endothelial cells.
