Increased lithogenicity of bile on fasting in normal subjects

The effect of fasting on bile lithogenicity was studied in 19 normal men and 22 normal women. The molar percentages of bile acid, phospholipid, and cholesterol, determined after random overnight fasts of 9, 12, and 16 hr, were plotted on triangular coordinates. The molar percentage of cholesterol increased in both men and women. Analysis using Admirand and Small's criteria for cholesterol saturation revealed that 4.50% of normal women were lithogenic at 9.1 hr and 54.5% at 16.5 hr (P less than 0.005). A similar trend in men was not significant. The mean values for both sexes were lithogenic at 16 hr only. Lithogenic bile was present in 4 men and 1 woman at 9 hr fasting and became more lighogenic with longer fasting. Analysis using the criteria of Hegardt and Dam revealed an increased proportion of both sexes moving into the metastable-labile and supersaturated zones on fasting, again with significant changes for women (P less than 0.01). The duration of fasting is important in interpreting the presence of lithogenic bile; although more pronounced in women, both sexes showed increased cholesterol saturation in bile with fasting.