Background: Dietary fat content influences bile salt metabolism, but quantitative data from controlled studies in humans are scarce.
Objective: The objective of the study was to establish the effect of dietary fat content on the metabolism of primary bile salts.
Design: The effects of eucaloric extremely low-fat (0%), intermediate-fat (41%; control diet), and extremely high-fat (83%) diets on kinetic values of cholate and chenodeoxycholate metabolism were determined after 11 d by using stable isotope dilution in 6 healthy men. All diets contained identical amounts of cholesterol.
Results: The total primary bile salt pool size was not significantly affected by dietary fat content, although the chenodeoxycholate pool was significantly higher during the low-fat diet. Fractional turnover rates of both primary bile salts were 30-50% lower during the low- and high-fat diets than during the control diet. Total hepatic bile salt synthesis was approximate to30% lower during both the high- and low-fat diets, but synthesis rates of the 2 primary bile salts were differentially affected. The molar ratio of cholate to total bile salt synthesis increased from 0.50 +/- 0.05 ((x) over bar +/- SD) to 0.59 +/- 0.05 and 0.66 +/- 0.04 with increasing fat intake, whereas the molar ratio of chenodeoxycholate to total bile salt synthesis decreased from 0.50 0.05 to 0.41 +/- 0.05 and 0.34 +/- 0.04. The relative concentration of deoxycholate in plasma increased during the low-fat period, which indicated increased absorption from the colon.
Conclusions: Both low- and high-fat diets reduce the synthesis and turnover rates of primary bile salts in humans, although probably through different mechanisms, and consequently they affect the removal of cholesterol from the body.
|Number of pages||7|
|Journal||American Journal of Clinical Nutrition|
|Publication status||Published - Apr-2004|
- dietary fat
- dietary carbohydrate
- bile salt
- stable isotope
- ACTIVATED RECEPTOR-ALPHA
- CHOLESTEROL 7-ALPHA-HYDROXYLASE GENE
- FRACTIONAL TURNOVER RATES
- CHENODEOXYCHOLIC ACID
- POOL SIZES