Dietary fat saturation, but not the feeding state, modulates rates of cholesterol esterification in normolipidemic men.

To determine whether the rates of cholesterol esterification in normal individuals are affected by diets differing in fats, nine men were randomly assigned to three groups receiving a diet rich in monounsaturated (MONO), polyunsaturated (POLY), or saturated (SAT) fat for 2 weeks using a crossover design. Subjects drank a dose of deuterium oxide, and the fractional esterification rate (FER) was calculated during fed and unfed periods. Total esterified cholesterol was calculated as the product of the FER and pool size, the latter obtained from a decay curve following injection of [4-14C]-cholesterol. The POLY diet produced the lowest serum cholesterol concentration and the SAT diet the highest (P < .001). For cholesterol ester (CE) deuterium enrichment, an interaction was noted between diet and time (P < .01). The FER was greater (P < .003) in subjects fed the POLY diet versus either of the other diets, although the amount of esterified cholesterol produced, expressed as either milligrams per day (P < .103) or milligrams per kilogram of body weight per day (P < .100), did not differ among groups. No effect of the feeding state was found for either the FER (P < .187) or total esterified cholesterol expressed as milligrams per day (P < .146) or milligrams per kilogram of body weight per day (P < .128). The results suggest that the diet fat type, but not the feeding state, may be responsible for serum esterified cholesterol concentrations.