ESSENTIAL FATTY-ACIDS AND SKIN PROPERTIES

Skin structure of terrestrial animals and definition of essential fatt y acids (EFA) are briefly reminded. Then, the lipid composition of nor mal epidermis (phospholipids, neutral lipids, sphingolilpids) and the levels of their major component EFAs (20:4n-6, arachidonic acid and pr incipally 18:2n-6, linoleic acid) were indicated. From observations co ncerning EFA-deficient rats and recent data on the physiological role of epidermal lipids, we deduce the structural and biological fonctions of 20:4n-6, 18:2n-6 and of other dietary fatty acids, 18:3n-6 (gamma- linoleic acid) and 20:5n-3 (eicosapentaenoic acid). Shortly, the impor tance of these EFAs, 18:2n-6 notably, in the transepidermal water loss and keratinization is underlined.