Lactose Diets and Cholesterol Metabolism

Abstract

Rabbits were fed sucrose- or lactose-containing diets and cholesterol varying from trace amounts to 0.5% of the diet for 8 to 13 weeks. The maximal difference in cholesterol metabolism and atherosclerosis between the groups fed sucrose or lactose was observed when 0.35% of cholesterol was added to the diet. Essentially no difference in serum and liver cholesterol values and atherosclerosis was obtained when 0.5% of cholesterol was added to the sucrose- and lactose-containing diets. The addition of 0.5 or 1% of succinylsulfathiazole (SST) to a 0.35% cholesterol-sucrose-containing diet fed to male rabbits for 8 weeks resulted in serum and hepatic cholesterol levels and atherogenesis comparable to that of the lactose-supplemented 0.35% cholesterol-containing diet. The supplementation of both SST and lactose in the diet produced essentially the same response in the rabbit as that obtained with either component alone added to the diet. During an 8-week experimental period, the restriction of the feeding pattern of rabbits given a 0.35% cholesterol-sucrose-containing diet for two or three onehour intervals daily resulted in higher serum and liver cholesterol values and degree of atherosclerosis than the corresponding values of the ad libitum-fed controls. This effect was not observed if the diet contained 29.35% of lactose in place of sucrose. Sucrose- or lactose-containing diets consisting of either a trace or 0.7% of cholesterol were fed to rabbits on a daily alternation schedule for 8 weeks. Serum and liver cholesterol content and atherogenesis was comparable to that observed in rabbits fed the corresponding carbohydrate diets containing 0.35% of cholesterol continuously. The serum cholesterol values of the sucrose-alternate-fed groups, however, were higher than the corresponding values for the sucrose-0.35% cholesterol-fed rabbits.