Fragrant rapeseed oil consumption prevents blood cholesterol accumulation via promoting fecal bile excretion and reducing oxidative stress in high cholesterol diet fed rats

Abstract

• Long-term effect of three rapeseed oils fed in hypercholesterolemic rats was tested. • Fragrant rapeseed oils lowered plasma cholesterol and boosted fecal bile acid efflux. • Fragrant rapeseed oils altered liver redox status and increased EPA and DHA output. • Such beneficial impact probably owed to high α-linolenic acid and polyphenols levels. We investigated the compositional changes and effects of long-term supplementation on blood lipids in three rapeseed oils [refined (RO), roasted at 120 °C (FO-120) and roasted at 150 °C (FO-150)]. Sixty Sprague-Dawley rats were fed either a basal diet or one of five high-cholesterol diets comprising lard, lard with cholestyramine, or three rapeseed oils for 12 weeks. Results showed that FO-120 and FO-150 alleviated plasma total cholesterol and increased fecal bile acid excretion, but RO had no significant effect. In the liver, cholesterol synthesis and conversion mRNA expression were altered by FO-120 or FO-150 feeding, like the inhibition of Hmgcr and activation of Cyp7a1 . Furthermore, FO-120 or FO-150 increased hepatic eicosapentaenoic and docosahexaenoic acid production and favorably improved hepatic redox status. Overall, the hypocholesterolemic effects may be attributed to their high levels of α-linolenic acid and polyphenols, linked closely to regulating cholesterol metabolism, promoting highly-unsaturated fatty acids synthesis, and reducing oxidative stress.