Olive Oils Improve Lipid Metabolism and Increase Antioxidant Potential in Rats Fed Diets Containing Cholesterol

Abstract

The effect of olive oils on lipid metabolism and antioxidant activity was investigated on 60 male Wistar rats adapted to cholesterol-free or 1% cholesterol diets. The rats were divided into six diet groups of 10. The control group (control) consumed the basal diet (BD) only, which contained wheat starch, casein, cellulose, and mineral and vitamin mixtures. To the BD were added 10 g/100 g virgin (virg group) or Lampante (Lamp group) oils, 1 g/100 g cholesterol (chol group), or both (chol/virg group) and (chol/Lamp group). The experiment lasted 4 weeks. Plasma total cholesterol (TC), LDL-cholesterol (LDL-C), HDL-cholesterol (HDL-C), triglycerides (TG), total phospholipids (TPH), HDL-phospholipids (HDL-PH), total radical-trapping antioxidative potential (TRAP), malondialdehyde lipid peroxidation (MDA), and liver TC were measured. Groups did not differ before the experiment. In the chol/virg and chol/Lamp vs chol group, the oil-supplemented diets significantly (P < 0.05) lessened the increase in plasma lipids due to dietary cholesterol as follows: TC (25.1 and 23.6%), LDL-C (39.3 and 34.7%), TG (19.3 and 17.0%), and TC in liver (36.0 and 35.1%) for the chol/virg and chol/Lamp group, respectively. The chol/virg and chol/Lamp diets significantly decreased the levels of TPH (24.7 and 21.2%; p < 0.05 in both cases) and HDL-PH (22.9 and 18.0%; p < 0.05 in both cases) for the chol/virg and chol/Lamp group, respectively. Virgin and Lampante oils in rats fed basal diet without cholesterol did not affect the lipid variables measured. Virgin, and to a lesser degree Lampante, oils have increased the plasma antioxidant activity in rats fed BD without cholesterol (an increase in TRAP, 20.6 and 18.5%; and a decrease in MDA, 23.2 and 11.3%, respectively). In the rats of chol/virg and chol/Lamp vs Chol diet groups the added oils significantly hindered the decrease in the plasma antioxidant activity (TRAP, 21.2 and 16.7%; and MDA, 27.0 and 22.3%, respectively). These results demonstrate that virgin, and to less degree Lampante, oils possess hypolipidemic and antioxidant properties. It is more evident when these oils are added to the diets of rats fed cholesterol. These positive properties are attributed mostly to the phenolic compounds of the studied oils.

Hazelnut Oil Administration Reduces Aortic Cholesterol Accumulation and Lipid Peroxides in the Plasma, Liver, and Aorta of Rabbits Fed a High-cholesterol Diet

“…36) The literature related to atherosclerosis has emphasized the beneficial effects of MUFA containing oils, especially olive oil, on lipids and lipid peroxidation. 3,[9][10][11][12][13][14] But the effects of HO consumption on serum lipids and lipid peroxides are not clearly known. In our study, an HO diet given alone to normal rabbits did not affect plasma or tissue lipids, or prooxidant-antioxidant status.…”

“…7,8) On the other hand, monounsaturated fatty acids (MUFAs), like PUFAs, have been reported to have antilipidemic effects. 3,9) Since MUFAs are resistant to oxidation, they may lower the susceptibility of the organism to lipid peroxidation [9][10][11][12] and LDL oxidation. 13,14) Olive oil, which is rich in MUFAs, and is known as an antiatherogenic oil, has been gaining importance in nutrition.…”

Methods of measurement and evaluation of natural antioxidant capacity/activity (IUPAC Technical Report)

“…In the rats of Chol/Virg and Chol/Lamp vs. Chol diet groups, the added oils significantly hindered the decrease in the plasma antioxidant activity (TRAP, 21.2 and 16.7 %; and MDA, 27.0 and 22.3 %, respectively). According to the used antioxidant assays (TRAP), virgin and to less degree other olive oils possess high antioxidant potential [113,114].…”

Hypolipidemic Activity of Olive Oil (Olea europaea) against High Fat Diet-Induced Nonalcoholic Fatty Liver Disease (NAFLD) in Mice

“…Gimeno E. et al, 2010 [23] reported that daily consumption of virgin olive oil about 2 tablespoons for 1 week helps in the lowering of LDL cholesterol oxidation and increases the antioxidant compounds in the blood. It has also been reported that olive oil maintained the plasma lipid pool by regulating the lipid peroxidation and antioxidant parameters [24]. Several studies in vitro suggest that, lipoxygenases, platelet aggregation and eicosanoid production were inhibited by olive oil phenolic compounds [25] [26].…”