The nutritional value of sunflower oils: linoleic sunflower seeds and seeds with high oleic content

Traditional sunflower oil has been the major polyunsaturated oil (high content in linoleic acid) used for many years in human nutrition to replace saturated fat, in an attempt to reduce cardio-vascular diseases linked to athero-thrombosis. Linoleic acid, the predominant dietary polyunsaturated fatty acid gave consistently lower plasma cholesterol, and slightly reduced triglycerides. Later on, it has been demonstrated that diets including high consumption of monounsaturated oils are as effective as those rich in polyunsaturated oils in lowering cholesterol (LDL-C), but in contrast to the effect of polyunsaturated diets, the monounsaturated diets do not lower HDL-C. Furthermore, the proposed oxidative theory for atherogenesis, the pro-thrombotic potential of high levels of dietary linoleic acid and the exceptional longevity of populations living in countries with high traditional monounsaturated diet (olive oil), prompted a reevaluation of the "benefits" linked to very high polyunsaturated diet. The development through natural selection of new sunflower seeds, producing oils enriched in oleic acid (high oleic sunflower oils - HOSO) at the expense of linoleic acid has made sunflower oils highly competitive compared to other traditional predominant monounsaturated oils. Furthermore the levels of anti-oxidant (tocopherols) and phytosterols naturally high in the traditional sunflower oils, which are preserved in these high oleic sunflower oils, could maintain a better protective effect compared to some other monounsaturated oils which present only low levels of phytosterols, but high levels of squalene. Finally, to obtain beneficial effects on athero-thrombotic parameters in human, it seems that an appropriate equilibrium between essen tial fatty acids could be main rained, by using different blends of oils, including traditional high linoleic sunflower oil, high oleic sunflower oil, plus rapeseed oil to obtain the minimum level of alpha-linolenic acid required to keep the proper n-6/n-3 balance. The potential effects of the new "mid-range-oleic" sunflower oils has to be investigated.