Reduced cholesterol absorption and intestinal solubilization by stearic acid-rich fats in rats

Stearic acid has been shown to be hypocholesterolemic relative to other long chain saturated fatty acids of shorter chain length. The present study examined the effect of stearic acid-rich fat consumption on cholesterol absorption and intestinal solubility Rats were fed diets with increasing amounts of stearate, containing either 16% fat from soybean oil (SBO), or 1% fat from soybean oil plus 15% fat from beef tallow (BT) (-19% 18:0) or cocoa butter (CB) (-34% 18:0). Dietary cholesterol was equalized at 0.125% A fourth diet contained 16% soybean oil with no cholesterol added (SBOn) In cholesterol fed animals, total liver cholesterol decreased as dietary stearate increased Cholesterol absorption efficiency among groups fed soybean oil was 52-53% Absorption in the BT group was significantly reduced to 47% and further reduced in the CB group to 29%. Among the groups fed diets containing cholesterol, the small intestinal contents aqueous phase cholesterol concentration decreased significantly as dietary stearic acid increased. There was a positive linear correlation between the means of aqueous phase intestinal cholesterol concentration and total liver cholesterol (r²=0.999, p<0.012) These results suggest that stearic acid-rich fats decrease cholesterol absorption by decreasing the solubilization of intestinal cholesterol.