Effect of dietary starches on the serum, aorta and hepatic lipid levels in cholesterol-fed rats

Abstract

The effect of long term feeding of purified rice starch and tapioca starch on the serum, aortic and hepatic lipid levels in cholesterol-fed rats has been studied and compared with the effect of glucose and sucrose. Glucose-fed rats had the lowest serum, aortic and hepatic cholesterol and phospholipids, while animals receiving sucrose showed the highest levels. Animals fed purified rice starch showed lower lipid levels than those of the sucrose group, while rice bran supplements lowered these levels still further. Whole ground paddy produced lipid levels significantly lower than either the purified rice starch group or the bran-supplemented group. Rats fed purified tapioca starch developed much lower serum, aortic and hepatic lipid levels than those of the rice starch group. Even though all fasting blood sugar levels were within normal range, levels 1 h after a glucose load were particularly elevated in the sucrose and rice starch groups. Myocardial lipoprotein lipase levels, which are known to be decreased in atherosclerosis, were also studied in the rats fed the various carbohydrates. The maximum decrease was found in the sucrose-fed group, rather than in the rice or tapioca starch groups. The hepatic levels of NAD and NADP were also studied. Total hepatic NAD and NADP levels, which are known to increase in atherosclerosis, were more elevated in the sucrose-fed group than in the rice-starch group, with the tapiocastarch group showing still lower values comparable to that of the glucose-fed group.