Gastrointestinal Absorption, Plasma Transport, Surface Distribution, and Urinary and Fecal Excretion of Radioactive Vitamin B₁₂ in Iron Deficiency

No evidence of vitamin B₁₂ deficiency or of any mechanism which might lead to vitamin B₁₂ deficiency, such as defective absorption or increased urinary or fecal excretion of the vitamin, has been found in iron-deficient subjects in whom gastric acid secretion and gastric biopsies were normal. It is concluded that when vitamin B₁₂ deficiency occurs in iron-deficient subjects it is the result of gastric atrophy. An unexplained finding was delayed disappearance of an intravenous dose of Co⁵⁸-B₁₂ from the plasma in iron-deficient subjects.