[Significance of evening primrose oil in the problem of the nutritional value of poly-unsaturated fatty acids].

The essential nutritional value of the polyunsaturated fatty acids can, in the light of present-day knowledge, be considered valid in all respects as regards the n-6 family which derives from linoleic acid. On the other hand, the polyunsaturated fatty acids of the n-3 family deriving from linolenic acid to not possess essential requisites as, for instance, they are ineffective for healing skin lesions caused by deficiency of polyunsaturated fatty acids. Unsaturated fatty acids taken in with the diet have a two-fold function: 1) plastic, insofar as they are necessary for the biosynthesis of the phospholipids; 2) regulatory, as precursors of prostanoids or eicosanoids (prostaglandins, thromboxanes, prostacyclins). The process of desaturation-lengthening that leads to the formation of these compounds is, however, limited by the activity of desaturase, which is in poor enough supply, especially in certain tissues, under physiological conditions and is almost non-existent in certain pathologies such as diabetes, alcoholism, anaemia and hypercholesterolaemia. The recent use of vegetable oils such as those obtained from the seeds of Evening Primrose, is of particular interest owing to the presence of gamma-linolenic acid, the product of the activity of desaturase. In the light of this unusual property, the recent nutritional-therapeutic results obtained by using this vegetable oil are described.