Effect of Pepsin on the Absorption of Food Vitamin B12 and Iron

Abstract

Using eggs from chickens injected with B₁₂⁵⁷Co and ⁵⁹Fe, we have studied the effect of in vitro peptic digestion on the absorption of egg vitamin B₁₂ and iron in 10 patients with pernicious anemia and 8 patients with acid gastric juice. The eggs were fed with neutralized normal human gastric juice, and absorption of the B₁₂ and iron measured by assay of fecal radioactivity. The mean of B₁₂ excretion in pernicious anemia patients fed pepsinized eggs was 76% compared to 81% in the same patients fed nonpepsinized eggs. This difference was significant only at the 0.15 level of probability. Patients with acid gastric juice excreted 61% of the fed egg B₁₂ and this was significantly lower than either value obtained in the pernicious anemia patients. In vitro peptic digestion did not affect iron absorption, and the patients with acid gastric juice did not absorb egg iron better than pernicious anemia patients. We suggest that peptic activity is important in food B₁₂ absorption.