THE SERUM LIPIDS IN MEN RECEIVING HIGH CHOLESTEROL AND CHOLESTEROL-FREE DIETS*

Abstract

Our previous studies suggested that 1700 to 4800 mg of dietary cholesterol provided as egg yolk produced marked increases in serum cholesterol. Recently we gave cholesterol as egg yolk in amounts similar to American intakes and compared this with the increase induced in the serum by crystalline cholesterol. Six healthy men, aged 41-52, were given a normal diet one week and subsequently a formula, each providing 3000 calories; 70 g protein and 133 g of fat. The fat was a vegetable oil mixture with saturated fatty acid composition similar to egg yolk. The iodine numbers of the diets for all periods were 84-86. The consecutive experimental periods of 3 weeks each were: I (cholesterol-free), II (egg yolk providing 475, 950 and 1425 mg of cholesterol for respective pairs of men), HI (cholesterol-free); and IV (crystalline cholesterol, 1200, 2400, or 3600 mg). During the egg yolk feeding, 11 to 33 g of the total fat was derived from egg yolk. The mean serum cholesterol decreased 57 mg % (p < 0.01) during the first cholesterol free period (I). The addition of egg yolk (II) led to an increase of 69 mg % (p < 0.001); no differences occurred among the 3 cholesterol intakes. With the 2d cholesterol-free formula (III), the serum cholesterol decreased 55 mg % (p < 0.001). In period IV, crystalline cholesterol increased the serum cholesterol 19 mg % (p< 0.01). Serum phospholipids changed in the same direction with the serum cholesterol. In diets equivalent in amounts and composition of fat the addition or subtraction of moderate amounts of cholesterol as egg yolk caused significant changes in serum cholesterol concentrations.