Effect of Small Intestinal Bacteria on Intrinsic Factor and the Vitamin B12-Intrinsic Factor Complex

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Abstract
The effect of bacteria isolated from small intestinal contents of blind loop patients on human intrinsic factor (IF) and the vitamin B12-IF complex was studied in vitro. After incubation of human gastric juice (HGJ) with bacterial cultures, there was a moderate reduction in IF-concentration, while the ability of HGJ to enhance the uptake of 57CoB12 by guinea-pig small intestinal brush borders was unaffected. Following incubation of HGJ-bound 57CoB12 with enterobacteria and bacteroides, the brush border uptake of 57CoB12 was not significantly different from control uptake, whereas the uptake after incubation with bifidobacteria was 79% of control uptake (p < 0.01). Significant release of unbound 57CoB12 could not be detected when HGJ-bound 57CoB12 was dialysed with bacterial cultures. Bacterial cell extracts from these cultures contained 57CoB12 partially bound, possibly to IF.