Fat absorption in germ-free and conventional rats artificially deprived of bile secretion.
Level 5 - mechanism / opinion, no new human data
Animal research
PubMed 7056496 · doi:10.1136/gut.23.1.49
What was done
Bile duct ligation was performed in germ-free and conventional rats to assess the role of gastrointestinal flora during bile deprivation. Researchers evaluated apparent absorption of dietary lipids (peanut oil), fecal lipid excretion (organic-soluble compounds and insoluble calcium soaps), individual fatty acid absorption profiles, and microbial biohydrogenation using 1-14C oleic acid.
What was found
Bile duct ligation reduced apparent dietary lipid absorption by approximately 50% in conventional rats compared to approximately 25% in germ-free rats. Deprivation of bile significantly increased fecal excretion of calcium soaps in both groups. Saturated fatty acids (16:0, 18:0) had larger absorption decreases than unsaturated fatty acids (18:1, 18:2). Conventional bile-deprived rats showed significantly lower absorption for all fatty acids except linoleic acid (18:2) compared to germ-free bile-deprived rats, and showed a negative digestive balance of stearic acid (18:0) associated with microbial biohydrogenation of dietary unsaturated fatty acids.
Why it matters
This study demonstrates that the intestinal microbiota aggravates dietary fat malabsorption during bile deficiency, partly through the biohydrogenation of unsaturated fatty acids into less absorbable saturated fats.
Limits
This is an animal study using surgically altered rats, which may not directly translate to human biliary obstruction. The abstract does not report exact sample sizes, numerical values for fecal lipid fractions, or specific dispersion statistics.
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