Preservation of micronutrients during rapeseed oil refining: A tool to optimize the health value of edible vegetable oils? Rationale and design of the Optim'Oils randomized clinical trial

Numerous micronutrients naturally abundant in oilseeds prevent the risk of cardiovascular diseases by reducing cholesterolemia and oxidative stress. These micronutrients include phytosterols and various antioxidants such as polyphenols, tocopherols and coenzyme Q10/Q9 but most of them are lost during the oilseed oil refining. The main objective of the Optim'Oil project was to modify the processes of oil refining in order to reduce the lost of micronutrients. Two clinical trials (cross-over, monocentric, randomized, double-blind and controlled) were designed to investigate the effect of an optimized rapeseed oil 1) on cardiovascular biomarkers (long-term study) and 2) on oxidative stress parameters (post-prandial study). For the long-term study, 59 volunteers ingested daily 20 g of oil and 22 g of margarine (optimized or standard) for 2 periods of 3 weeks separated by a 3-week wash-out period. Blood samples were collected at the beginning and at the end of each period. For the post-prandial study, a sub-group of 16 volunteers came fasted at the laboratory and took 300 mL of a test meal containing 60% of the optimized or standard oils. Blood samples were collected before and during 6 h after the test meal intake. In comparison with the standard oil and margarine, the optimized oil and margarine exhibit as expected an increased content of phytosterol (+ 22%), polyphenols (×11), tocopherols (+ 131%) and coenzyme Q10/Q9 (+ 165%). Overall, conditions of this study were relevant to investigate the effect of the optimized rapeseed oil and margarine on the cardiovascular risk and the oxidative stress.