Effects of endogenous and exogenous micronutrients in rapeseed oils on the antioxidant status and lipid profile in high-fat fed rats

BACKGROUND: Micronutrients in oil reduce one or more risk factors of cardiovascular diseases, while the contents of micronutrients in oil are relatively poor, which is insufficient to reverse the metabolic disorders at different stages of progress. The aim of this study was to investigate the effects of endogenous micronutrients in optimized cold-pressed rapeseed oil and restoratively added or fortified micronutrients in traditional refined rapeseed oil (restoring micronutrients to be nearly equal to or significantly higher than levels in crude rapeseed oil) on the antioxidant status and lipid profile in high-fat fed rats. METHODS: Male Wistar rats were fed high-fat diets containing different rapeseed oils for 4 weeks, including the standard refined rapeseed oil(SRO), optimized cold-pressed rapeseed oil(CRO) and the traditional refined rapeseed oil with restorative addition or fortification of micronutrients (LF, HF-SRO). RESULTS: CRO exhibited significant increases in contents of tocopherols (+13%), phytosterols (+34%), polyphenols (+92%) and phospholipids (+725%) compared with SRO, as well as the total antioxidant capacities (+82-125%) (p < 0.05). While the HF-SRO revealed improved antioxidant properties in vitro than the CRO, which was comparable to LF-SRO. Significant improved plasma antioxidant capacities and lipid peroxidation evaluated by T-AOC, GSH, tocopherols and MDA were found in rats fed HF-SRO when compared with CRO and LF-SRO (p < 0.05). Furthermore, HF-SRO also decreased the plasma and hepatic TC levels compared to CRO and LF-SRO, accompanying higher fecal cholesterol excretion (p < 0.05). CONCLUSION: The standard refined rapeseed oil with fortification, not restorative addition of micronutrients was comparable to the optimized cold-pressed rapeseed oil in improving the antioxidant status and lipid profile of high-fat fed rats.