Low-fat, high-carbohydrate and high-fat, low-carbohydrate diets decrease primary bile acid synthesis in humans.

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.