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

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.

Key-words:

• Intestinal microorganisms
• intrinsic factor
• vitamin B₁₂