The effects of feeding various carbohydrates on the development of hypercholesterolemia and atherosclerosis.

It is possible to establish atherosclerosis in rabbits by feeding semi-synthetic diets that are high in carbohydrate and saturated fat and devoid of cholesterol. Addition of saturated fat to laboratory chow does not render the chow atherogenic. When rabbits were fed diets which differ only in the carbohydrate component, starch was found to be more atherogenic than sucrose which, in turn, was more atherogenic than glucose. All the diets were hypercholesteremic and hypertriglyceridemic. In another series of experiments diets containing fructose or sucrose were more atherogenic than diets containing glucose, lactose or sorbitol. Baboons were feed semi-synthetic diets containing fructose, sucrose, starch or glucose (but no cholesterol) for one year. Serum cholesterol levels were 155-165 mg/dl in all test groups. The normal baboon cholesterol level is 115 mg/dl. Serum triglycerides were elevated from the normal level of 73 mg/dl to about 110 mg/dl in the groups fed starch and glucose and to about 125 mg/dl in the groups fed fructose and sucrose. Liver and lung cholesterol ester levels were also raised. The test groups all showed aortic sudanophilia. The most severe sudanophilia was observed in the fructose group (11.2% of surface area) and the least in the glucose group (6.2% of surface area). The biliary cholesterol specific activities (after administration of (3-H)-melvalonic acid) were the same in all groups, but biliary bile acid specific activity was higher in the control baboons than in test animals. These data, plus the higher primary/secondary bile acid ratio observed in the test animals, suggest that reduced bile acid synthesis may be one cause of the hypercholesteremia observed in animals fed the semi-synthetic diets.