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 6h 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.

Foods with a high fat quality are essential for healthy diets.

Fat is generally a highly valued element of the diet to provide energy, palatability to dry foods or to serve as a cooking medium. However, some foods rich in fat have a low fat quality with respect to nutrition, i.e., a relative high content of saturated (SFA) as compared to unsaturated fatty acids, whereas others have a more desirable fat quality, i.e., a relative high content of unsaturated fatty acids as compared to SFA. High-fat dairy products and fatty meats are examples of foods with low fat quality, whereas vegetable oils (tropical oils such as palm and coconut oil excluded) are products with a generally high fat quality. The aim of this paper is to explore the nutritional impact of products made of vegetable oils, e.g. margarines and dressings, and how they can be designed to contribute to good health. Since their first industrial production, the food industry has endeavored to improve products like margarines, including their nutritional characteristics. With evolving nutrition science, margarines and cooking products, and to a lesser extent dressings, have been adapted to contain less trans fatty acids (TFA), less SFA and more essential (polyunsaturated, PUFA) fatty acids. This has been possible by using careful fat and oil selection and modification processes. By blending vegetable oils rich in the essential PUFAs alpha-linolenic acid (vegetable omega-3) or linoleic acid (omega-6), margarines and dressings with both essential fatty acids present in significant quantities can be realized. In addition, full hydrogenation and fat rearrangement have enabled the production of cost-effective margarines virtually devoid of TFA and low in SFA. Dietary surveys indicate that vegetable oils, soft margarines and dressings are indeed often important sources of essential fatty acids in people's diets, whilst providing negligible amounts of TFA and contributing modestly to SFA intakes. Based on empirical and epidemiological data, the public health benefit of switching from products with a low fat quality to products with a high fat quality can be predicted. For example, switching from butter or palm oil to a soft margarine shows a substantial improvement in the nutritional quality of the diet. These simple, practical dietary adaptations can be expected to contribute to the healthy growth and development of children and to reduce the burden of cardiovascular disease.