Cholesterol Production in Obesity

Abstract

Sterol-balance studies were performed in 10 control subjects, 10 normolipidemic obese patients, and 10 hypertriglyceridemic (type IV, mostly obese) patients on a low-cholesterol solid-food diet. Fecal elimination of cholesterol was markedly elevated in the overweight patients and tended to be high in the hypertriglyceridemic subjects also. A significant correlation was found between body weight and fecal excretion of neutral, acidic, and total steroids, indicating that the greater the body weight the higher was the rate of cholesterol synthesis. Sterol-balance data in obese subjects showed that excess daily cholesterol production roughly amounted to 20 mg/kg of adipose tissue. The control subjects produced only 12 mg/kg of body weight daily. Thus, obesity is associated with an increased rate of cholesterol synthesis in man. However, the correlation between serum cholesterol concentration and cholesterol production was low, suggesting that the overall rate of cholesterol synthesis was not the only factor determining the serum cholesterol level. That enhanced cholesterol production is not an irreversible phenomenon in obese subjects was indicated by the normalization of sterol-balance values in three overweight patients after their weights had been reduced by total fast followed by a low-calorie diet.