Cholesterol vehicle in experimental atherosclerosis. III. Effects of absence or presence of fatty vehicle

Three separate experiments show that cholesterol administered to rabbits in the absence of added fat is more atherogenic than cholesterol fed together with corn oil. When cholesterol is dissolved in the corn oil (by heating) prior to mixing with the diet, it is more atherogenic than when it is suspended in the oil. In every case the lowest serum and liver cholesterol levels were observed in the group not receiving corn oil. Gas chromatography of the fatty acids of the serum cholesterol esters of pooled sera suggest that there are smaller amounts of unsaturated C 18 fatty acids in the cholesterol‐no fat group. Deficiency in these unsaturated acids may be the cause of the high atherogenicity of the cholesterol‐no fat diet. There is also a lower proportion of unsaturated fatty acids in the triglycerides of this group. Heating of corn oil 10 min, at 160–200(°C.) causes an increase of titratable fatty acid in the oil (0.005 m‐equiv./g. to 0.088 m‐equiv./g. or 0.14% FFA to 2.5% FFA). The relatively large amounts of free unsaturated fatty acids in the heated oil may be the cause of the greater atherogenicity of the solution, as compared to the suspension, of cholesterol in corn oil.