Effect of different dietary fats on daily loss of sterols from the skin of man.

We studied the effect of polyunsaturated dietary fat upon the 24-hour loss of cholesterol and other sterols from the skin surface of 4 human subjects. They were fed cholesterol-free diets which provided 40% of the total caloric intake from saturated fat (cocoa butter) and then a highly polyunsaturated fat (corn oil). In both dietary fat periods, the daily loss of cholesterol through the skin was similar, 91 and 87 mg in the saturated and polyunsaturated fat periods, respectively. 87 and 89% of the total cholesterol were in the esterified form in the saturated and polyunsaturated dietary fat periods. The sterol composition of the skin surface lipid was not altered. The study suggests that the plasma cholesterol-lowering effect of dietary polyunsaturated fat was not mediated by a change in the loss of cholesterol through human skin.