Dietary psyllium increases fecal bile acid excretion, total steroid excretion and bile acid biosynthesis in rats.
Level 5 - mechanism / opinion, no new human data
Animal study evaluating physiological mechanisms without human data
PubMed 9649606 · doi:10.1093/jn/128.7.1199
What was done
Four groups of 10 rats were fed semipurified diets for 3 weeks containing either 5% cellulose (control), 5% cellulose plus 1% cholic acid, 5% cellulose plus 2% cholestyramine, or 5% psyllium hydrocolloid. Researchers measured liver cholesterol concentration, fecal bile acid and total steroid excretion, and hepatic cholesterol 7alpha-hydroxylase (7alphaOHase) enzyme activity and mRNA levels.
What was found
The abstract does not report exact numerical values or effect sizes. Rats fed psyllium or cholestyramine had significantly lower liver cholesterol content than cellulose controls, while cholic acid feeding resulted in significantly higher liver cholesterol than all other groups. Fecal bile acid and total steroid excretion were significantly higher in the psyllium, cholestyramine, and cholic acid groups compared to control. Both 7alphaOHase activity and mRNA levels were significantly higher in the psyllium and cholestyramine groups than in the cellulose or cholic acid groups.
Why it matters
The study demonstrates that psyllium reduces liver cholesterol in rats by increasing fecal steroid excretion and up-regulating bile acid biosynthesis at both the transcriptional and enzymatic levels.
Limits
This was an animal study conducted over a short duration (3 weeks); rodent bile acid metabolism may not translate directly to humans. The abstract omits numerical values, variance, and exact statistical test results.
Cited by
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