THE EFFECT OF DIETARY FAT ON BILE ACID METABOLISM IN MAN

The influence of dietary fat on the biliary bile acid metabolism was studied in a 22-year-old male volunteer by using cholic acid-24-C14. The subject was maintained for 3 successive 15-day periods on homogenized formula diets which provided 45% of calories from butterfat or corn oil, or which were fat-free. The cholic acid turnover was assessed during the final 9 days of each period by analyzing bile samples obtained from the duodenum. On butterfat the daily cholic acid production was 0.13 g, while on corn oil and the fat-free diet it was 0.28 and 0.25 g, respectively. On changing from a free choice to a formula type diet, the glycine/taurine conjugation ratio decreased abruptly from about 2 to nearly 1, and remained at this level as long as the homogenized diet was fed. There was an increase in the proportion of cholic and a corresponding decrease in the deoxycholic acid in the bile with both high fat diets. The reverse changes in these bile acid proportions were associated with the fat-free diet. The fluctuations in the relative concentrations of the other bile acids were less pronounced.