Effect of Bacteria on Intestinal Uptake of Vitamin B₁₂

Abstract

Preincubation in vitro of intrinsic-factor-(IF-)bound vitamin B₁₂ with populations of Escherichia coli and Bacteroides fragilis reduced intestinal uptake and absorption of the vitamin from the mixture in rats, as compared to application of vitamin not exposed to living bacteria. Strains of Streptococcus faecalis and Bifidobacterium were without such effects. In vitro uptake of IF-bound vitamin B₁₂ by E. coli and B. fragilis was high, while the uptake by Str. fœcalis and Bifidobacterium was minimal. The results suggest that uptake by intestinal bacteria of IF-bound vitamin B₁₂ may contribute to the malabsorption of the vitamin in the blind-loop syndrome.

Key-words:

• Intestinal absorption
• intestinal microorganisms
• intrinsic factor
• vitamin B₁₂