Influence of type of carbohydrate on atherosclerosis in baboons fed semipurified diets plus 0.1% cholesterol

Abstract

Five groups of six (three male, three female) baboons (Papio ursinus) were maintained for 17 months on a semipurified diet containing 40% carbohydrate, 25% casein, 13.9% coconut oil, 0.1% cholesterol, 15% cellulose, 5% salt mix (USP XIV) and 1% vitamin mix. The carbohydrates fed were: fructose, sucrose, starch, glucose, and lactose. A fifth group was used as control and was fed bread, fruit, and vegetables. Serum, liver, and tissue lipids were analyzed at the end of the feeding period as were cholesterol absorption (as 3H-cholesterol) and synthesis (from 14C-mevalonic acid). Serum cholesterol and beta-lipoprotein levels were elevated in all the test groups compared to final control levels or to starting levels for all the baboons. Average serum cholesterol levels of the test groups were not significantly different. Liver lipids were elevated in all test groups except that fed glucose. Baboons on the test diets absorbed more exogenous cholesterol (3H) but biosynthesis of this sterol was not inhibited. The ratio of biliary primary/secondary bile acids was below normal levels only in the animals fed fructose and sucrose. Cholesteryl ester fatty acid spectra of serum and liver reflected the dietary fat. Fecal weight was 69% higher in lactose fed animals and 31% lower in sucrose fed animals than in the controls. The ratio of endogenous or exogenous neutral/acid steroids was considerably lower in the fructose-fed baboons than in the other animals. On this diet average aortic sudanophilia (percentage of surface) was: fructose, 11.3; sucrose, 10.4; starch, 21.3; glucose, 17.2 lactose, 65.8; and control, 1.4. Gross atheromatous lesions were seen in five of six baboons fed lactose; three of six baboons fed fructose; two of six baboons fed sucrose, and one of six baboons fed starch. In a second experiment three groups of baboons were fed the control diet, the semipurified diet in which the carbohydrate was lactose, and the semipurified diet containing lactose plus 0.1% cholesterol for 8.5 months. Serum lipids were elevated in the two test groups but liver lipids were not significantly different from control levels. Average aortic sudanophilia (percentage of area) was: lactose, 2.2; lactose-cholesterol, 20.8; and control, 0.3%. One of the six baboons in the lactose-cholesterol group had visible atherosclerotic lesions. These experiments represent the first successful attempt to produce severe atherosclerosis in baboons by dietary means alone.

Metabolic Syndrome in the Rat: Females are Protected Against the Pro-Oxidant Effect of a High Sucrose Diet

“…The sucrose-induced increase in TG-rich lipoprotein and increased lipoprotein susceptibility to peroxidation are factors that may combine to increase risk of cardiovascular diseases (29). Compared with starch feeding, sucrose feeding thus results in a higher occurrence of aortic atherosclerotic plaque in animal models as previously reported (30). Moreover, we found that heart tissue from male sucrose-fed rats was more susceptible to in vitro peroxidation than that from the starch group.…”

Lipid Metabolism and Antioxidant Status in Sucrose vs. Potato-Fed Rats

“…An increase in the TG-rich lipoprotein levels and in the lipoproteins' susceptibility to peroxidation are factors that may contribute to an increased risk of developing cardiovascular diseases. Compared with the potato-based diet, sucrose consumption resulted in a higher frequency of aortic atherosclerotic plaques in animal models, consistent with previous reports [43].…”

Effect of Lactose Content of Nonfat Milk Diets on Male Rat Serum Lipids and Lipoproteins

“…Earlier Wells and Anderson [11] found lactose to be hypercholesterolemic in rabbits, but these findings were not substantiated by Kritchevsky et al [12], Kritchevsky et al [13] did, however, observe an increased incidence o f atheroscle rosis in baboons fed 0.1 % cholesterol in a 40% lactose diet as compared to fructose, glucose, sucrose or starch.…”