RESISTANT STARCH DECREASES SERUM TOTAL CHOLESTEROL AND TRIACYLGLYCEROL CONCENTRATIONS IN RATS

Rats were meal-fed semipurified diets containing a low (0.8 g/MJ) and a high (9.6 g/MJ) amount of resistant starch (RS) or various amounts o f RS (0.8 to 9.6 g/MJ) and guar gum (0 to 8.8 g/MJ). In one experiment , rats were fed the low and high RS diets in three dietary regimens (a d libitum consuming, 12 h ad libitum/12 h food deprived, and meal fed) . Effects of RS and guar gum on serum postprandial and postabsorptive concentrations of total cholesterol (TC) and triacylglycerol (TAG), gr owth, hydrogen excretion, tissue weights and contents of small intesti ne and cecum, and pH of cecal contents were investigated. In addition, effects of RS on food intake, de novo hepatic synthesis of fatty acid s and neutral sterols, and on lipoprotein lipase activity and weight o f epididymal fat pads were investigated. Compared with feeding the low RS diet, the high RS diet reduced the serum TC and TAG concentrations , with these effects observed after 1 and 2 wk of feeding, respectivel y. The dietary regimen did not influence the effect of RS on the serum TC and TAG concentrations, but it did affect the serum TAG concentrat ion. Resistant starch had no effect on the hepatic synthesis of fatty acids and neutral sterols or on the lipoprotein lipase activity in epi didymal fat pads. Guar gum also reduced the serum TC concentration, bu t it had no effect on serum TAG concentration. The tissue weights and contents of small intestine and cecum as well as hydrogen excretion in creased with increasing amounts of dietary RS and guar gum, whereas th e pH of cecal contents decreased. No effects of RS on food intake and total body weight gain were found, whereas guar gum decreased weight g ain. Feeding the high RS diet also led to a lower weight of the epidid ymal fat pads. We conclude that dietary RS can reduce serum TC and TAG concentrations and fat accretion.