The effect of consuming oxidized oil supplemented with fiber on lipid profiles in rat model*

BACKGROUND This study was conducted to evaluate the effects of consuming thermally oxidized oil supplemented with pectin on liver glutathione peroxidase activity, serum malondialdehyde and lipid profiles in male Sprague-Dawley rats. METHODS Fifty growing male Sprague-Dawley rats were randomly divided into different groups. The diets differed only in their fat and pectin content. The diets had fresh sunflower oil or thermally oxidized sunflower oil. The diets were supplemented with pectin in the amount of 50 g/kg diet or not supplemented. Thus, there were four experimental groups: "fresh oil", "oxidized oil", "fresh oil + pectin", "oxidized oil + pectin". Study duration was 42 days. Non parametric, Kruskal-Wallis and Mann-Whitney tests were used to evaluate mean values of variables in groups. RESULTS In oil consumption, peroxide, p- Anisidine, thiobarbituric acid, free fatty acid values and total polar compounds increased but iodine value was decreased. In the oxidized oil group compared to the fresh oil group, total cholesterol, high density lipoprotein cholesterol and malondialdehyde increased (p < 0.05). Serum malondialdehyde was decreased in the "oxidized oil + pectin" group compared to the oxidized oil alone (2.82 ± 0.51 vs. 3.61 ± 0.72 nmol/ml; p < 0.05). Total cholesterol decreased in both groups containing pectin compared to their respective diets without supplementation (70.10 ± 10.75 vs. 81.20 ± 13.10 mg/dl; p < 0.05). CONCLUSIONS Pectin consumption could decrease serum malondialdehyde and cholesterol in the diet that contains oxidized oil. Pectin supplementation could decrease the detrimental effects of thermally oxidized oil.