Effect of sesame oil on serum and liver lipid profiles in the rat.

In our previous study (Satchithanandam, S., Reicks, M., Calvert, R.J., Cassidy, M.M. and Kritchevsky, D. (1993) J. Nutr. 123, 1852-1858), we found that the absorption of lymphatic cholesterol by rats fed diets containing 24% sesame oil was about 50% less than that by rats fed the control diet containing no sesame oil. The effect of sesame oil on serum cholesterol levels was not determined at that time. In the present study, three groups of male Wistar rats (75-100 g) were fed a control diet or a diet containing 12 or 24% sesame oil. To increase serum cholesterol levels, 1% cholesterol and 0.5% cholic acid were added to each diet. After rats were fed for 4 weeks, total cholesterol, LDL-cholesterol, HDL-cholesterol, and triglyceride levels were measured in the serum. Liver weight and cholesterol and triglyceride levels were determined. Liver cholesterol levels were significantly lower in rats fed the 24% sesame oil diet, and the liver lipid level was significantly higher in the 24% sesame oil-fed group, compared with levels in the group fed the control diet. Liver weights and esterified cholesterol and liver triglyceride levels were not significantly different among the groups. Levels of serum total cholesterol and LDL-cholesterol were significantly lower in rats fed the 24% sesame oil diet, compared with levels in the control group. Serum triglyceride and HDL-cholesterol levels did not differ significantly among the groups. The mechanism by which a diet containing 24% sesame oil reduces levels of serum and liver cholesterol, liver LDL cholesterol, and liver lipids is not known. However, the high degree of unsaturation (85%) of sesame oil and the presence of linoleic acid may be important factors.