Seed oils improve lipid metabolism and increase antioxidant potential in rats fed diets containing cholesterol

Abstract

The goal of this investigation was to find the most valuable among four often-used seed oils for atherosclerosis preventing diets. Fatty acids, sterols, antioxidant compounds, stability and total radical-trapping antoxidative potential (TRAP) in sunflower, sunflower high oleic, rapeseed and grapeseed oils were determined. The highest stability and the highest TRAP (3.8 Rancimat 120°C, hours and 324 nmol/ml) and the lowest stability and the lowest TRAP (2.4 Rancimat 120°C, hours and 201 nmol/ml) were in rapeseed and sunflower oils, respectively. The effect of these two seed oils on lipid metabolism and antioxidant activity was investigated on 60 (divided in six diet groups of 10) male Wistar rats adapted to cholesterol-free or 1% cholesterol diets. The control group (Control) consumed basal diet (BD) only. To the BD were added 10g/100g rapeseed (Rapeseed group) or sunflower (Sunflower group) oils, 1 g/100 g cholesterol (Chol group) or both (Chol/Rapeseed group) and (Chol/Sunflower group). The experiment lasted 4 weeks. In the Chol/Rapeseed and Chol/Sunflower vs. Chol group, the oil supplemented diets significantly ( P < 0.05) hindered the rise in plasma lipids due to dietary cholesterol. Rapeseed and to less degree sunflower oils have increased the plasma antioxidant activity in rats fed BD without cholesterol (an increase in TRAP: 20.8% and 16.0% and a decrease in MDA: 22.0% and 14.9%, respectively). In the rats of Chol/Rapeseed and Chol/Sunflower vs. Chol diet group the added oils significantly hindered the decrease in the plasma antioxidant activity (TRAP: 21.7% and 16.3% and MDA: 26.2% and 21.5%, respectively). Therefore, rapeseed and to less degree sunflower oils possess hypolipidemic and antioxidant properties. It is more evident when these oils are added to the diets of rats fed cholesterol. In conclusion, rapeseed oil has high organoleptic properties and the highest antioxidant capacity. Its influence on plasma lipid levels and antioxidant potential is significantly higher than of oils with relatively low antioxidant capacity. The above-mentioned properties make rapeseed oil preferable choice for atherosclerosis preventing diets.