Replacing saturated fat with PUFA-rich (sunflower oil) or MUFA-rich (rapeseed, olive and high-oleic sunflower oil) fats resulted in comparable hypocholesterolemic effects in cholesterol-fed hamsters

Recent studies have suggested that monounsaturated fatty acid (MUFA)-rich d ietary fats do not have the same plasma cholesterol-lowering effects whereb y rapeseed oil was more effective than olive oil. This phenomenon could be explicable by the content of other fatty acids or plant sterols. To further evaluate the effects of different MUFA-rich oils (18:1-rich sunflower oil, rapeseed oil, olive oil) in comparison to polyunsaturated (PUFA)-rich oils (18:2-rich sunflower oil) and saturated fat (palm stearin) on cholesterol and bile acid metabolism, male Syrian golden hamsters were fed semipurified diets containing 5% fat and 0.2% cholesterol for 5 weeks. To test whether oil refining would have an impact on the cholesterol-lowering potential, un refined and refined varieties of rapeseed and olive! oil were included. Aft er 5 weeks, plasma total cholesterol (TC) was highest with palm stearin (10 .0 +/- 2.6 mmol/l) while the MUFA- or PUFA-rich fats significantly lowered IC. The lowest TC concentrations were found with refined rapeseed, cold pre ssed rapeseed and 18:2-rich sunflower oil (6.7 +/- 1.2; 7.1 +/- 0.7 and 7.1 +/- 0.7 mmol/l, respectively), whereas TC was 18-15% high er (not signific ant) with 18:1-rich sunflower, virgin and refined olive oil. Liver choleste rol concentrations were lowest in hamsters fed palm stearin or 18:2-rich su nflower oil while MUFA-rich fats increased hepatic cholesteryl ester accumu lation, especially of cholesteryl oleate. There were no significant differe nces in the fecal neutral sterol and bile acid excretion. These data demons trate that MUFA-rich dietary fats, e.g. rapeseed, olive and 18:1 rich sunfl ower oil, are comparable in their hypocholesterolemic potential and cause s imilar effects on plasma cholestero as 18:2-rich sunflower oil in hamsters when the dietary cholesterol intake is moderate.