Increases in hyperlipoproteinemia, disturbances in cholesterol metabolism and atherosclerosis induced by dietary restriction in rabbits fed a cholesterol‐rich diet

Abstract

The influence of dietary restriction on cholesterol transport and metabolism was investigated in rabbits given standard or cholesterol-rich diets (0.2 g cholesterol/kg body weight daily) either ad libitum or with 50% caloric ration. Dietary restriction which has only a slight influence in control rabbits markedly aggravated the disturbances induced by exogenous cholesterol. With limited feeding, control rabbits presented a moderate increase in plasma cholesterol, whereas marked aggravation of hypercholesterolemia was observed in cholesterol-fed rabbits. Analysis of the lipoprotein profile showed that the excess of plasma cholesterol with the restricted cholesterol-rich diet corresponded to an increase in the concentration of very low density lipoprotein (VLDL) and low density lipoproteins (LDL) without any additional changes in the composition of these lipoproteins. No significant change appeared in the high density lipoprotein (HDL) concentration. The parameters of cholesterol metabolism were determined, from the curves of [3H]cholesterol radioactivity decrease, using a two-pool model. The increase in cholesterol turnover rate induced by the cholesterol-rich diet was accentuated by dietary restriction, whereas rabbits on standard restricted diet showed a slight decrease. The large increase in the size of both pools A and B in cholesterol-fed rabbits was even more pronounced with limited feeding. Dietary restriction induced additional accumulation of cholesterol in the aortic wall and the grade of the lesions was also aggravated.

Effect of Behavioral Interventions on Insulin Sensitivity and Atherosclerosis in the Watanabe Heritable Hyperlipidemic Rabbit

“…Interestingly, total serum cholesterol increased dramatically in the diet group compared with the other 2 groups. Although dietary restriction and weight loss in humans typically leads to a reduction in serum cholesterol, it has been reported that diet-restricted, cholesterol-fed NZW rabbits exhibit hypercholesterolemia, including elevations in LDL and VLDL cholesterol (22,23).…”

Metabolism of cholesterol and triglycerides in young pigs fed beef-based, soy-based, or conventional diets

“…Reitman et al (1982) found plasma cholesterol concentrations in excess of 700 mg/dl when miniature swine were fed diets containing 15% beef tallow and 1.5% cholesterol. In our study, diets that contained less than 0.1% cholesterol (equivalent to a daily intake of approximately 2500 mg in a 70 kg man) produced small but significant increases in plasma cholesterol concentrations in both beef-and soy-fed pigs (Table 7) Liepa et al, 1980;Lacombe et al, 1983), but the effects of restriction vary with species and with length and degree of restriction.…”

“…Lacombe et al (1983) further demonstrated that the cholesterol content of the diet influences the effects of caloric restriction on cholesterol metabolism. In the study by Lacombe et al (1983), rabbits fed a cholesterol-free diet at 50% of ad libitum intake had only moderate increases in plasma cholesterol, while restricted-fed rabbits receiving a cholesterol-rich diet had marked hypercholesterolemia and a greater degree of atherosclerosis.…”

“…The study included two separate feeding trials to examine the differential effects of the three experimental diets at two degrees of dietary intake restriction (approximately 65% and 90% of ad libitum intake). Degree of dietary restriction has been found to significantly affect lipid metabolism and atherogenesis Liepa et al, 1980;Etherton et al, 1982;Lacombe et al, 1983). The specific objectives of this study were to determine the apparent absorption by pigs of nutrients in conventional swine diets versus more human-type beef-and soy-based diets and to determine the effects of these diets on body weight gain, body composition, and plasma lipid and urea nitrogen concentrations.…”

“…Studies have demonstrated an effect of dietary restric tion on cholesterol metabolism and(or) atherogenesis in several species (Rodbard et al, 1951;Lacombe et al, 1983), including humans , with conflicting results. The results of such studies are difficult to interpret because of many con founding factors, such as the degree of restriction, the nutrient restricted, the duration of restriction, the period during the life span when studied, and the species examined.…”