Impaired Assimilation of EGG CO57 Vitamin B12 in Patients With Hypochlorhydria and Achlorhydria and After Gastric Resection

Abstract

Abstract Patients who have undergone gastric resection and those with simple gastric hypochlorhydria and achlorhydria may have low serum B 12 concentrations with normal absorption of radiocyanocobalamin. Impaired assimilation of food vitamin B 12 , but not of the crystalline Co 57 B 12 , may be the cause for this phenomenon. This hypothesis was tested by comparing the assimilation of Co 57 B 12 incorporated into eggs in vivo with that of crystalline Co 57 B 12 . As judged by the urinary excretion test, 10 patients with gastric resection having low serum B 12 , values and normal absorption of crystalline B 12 , absorbed on the average 9% of that observed in 11 normal control subjects when the egg Co 57 B 12 was administered. Similarly, 5 patients with achlorhydria or severe hypochlorhydria absorbed on the average 12% of that seen in normal subjects. There was no difference in the absorption of the crystalline Co 57 B 12 in these groups. An equally poor assimilation of nonlabeled food B 12 may explain the low serum B 12 concentrations found in postgastrectomy patients, and achlorhydric subjects with low serum B 12 and normal absorption of crystalline radiocyanocobalamin. Patients with pernicious anemia and those with gastric resection showing low serum B 12 concentrations and B 12 absorption values had extremely poor assimilation of both food Co 57 B 12 and crystalline Co 57 B 12 .