EFFECT OF DIETARY FATS RICH IN LAURIC, MYRISTIC, PALMITIC, OLEIC OR LINOLEIC-ACID ON PLASMA, HEPATIC AND BILIARY LIPIDS IN CHOLESTEROL-FED HAMSTERS

Effects of different dietary fats on plasma, hepatic and biliary lipid s were determined in male golden Syrian hamsters (Mesocricetus auratus ) fed on purified diets for 7 weeks. Diets were made by blending diffe rent fats containing characteristic fatty acids: butter (14:0 + 16:0), palm stearin (16:0), coconut oil (12:0 + 14:0), rapeseed oil (18:1), olive oil (18:1) and sunflowerseed oil (18:2). In all diets except the sunflowerseed oil diet dietary 18:2 was held constant at 2 % energy. Total fat supplied 12 % of energy and cholesterol was added at 4 g/kg diet. Plasma cholesterol and triacyglycerol concentrations were increa sed by dietary cholesterol. After 7 weeks, plasma cholesterol concentr ations were highest with the palm stearin, coconut oil and olive oil d iets (8.9, 8.9 and 9.2 mmol/l) and lowest with the rapeseed oil and su nflowerseed oil diets (6.7 and 5.5 mmol/l) while the butter diet was i ntermediate (8.5 mmol/l). Hepatic cholesterol concentration was highes t in hamsters fed on the olive oil diet and lowest with the palm stear in diet (228 v. 144 mu mol/g liver). Biliary Lipids, lithogenic index and bile acid profile of the gall-bladder bile did not differ signific antly among the six diets. Although the gallstone incidence was genera lly low in this study, three out of 10 hamsters fed on the palm steari n diet developed cholesterol gallstones. In contrast, no cholesterol g allstones were found with the other diets. Rapeseed and sunflowerseed oils caused the lowest plasma cholesterol and triacyglycerol concentra tions whereas olive oil failed to demonstrate a cholesterol-lowering e ffect compared with diets rich in saturated fatty acids. Since 18:2 wa s kept constant at 2 % of energy in all diets, the different responses to rapeseed and olive oils could possibly be attributed to their diff erent contents of 16:0 (5.6 % v. 12.8 % respectively). Other possible explanations are discussed.