Hi Ben, long time no see... On Sat, 17 Aug 2002 21:22:58 +1000, Balzer, Ben <[log in to unmask]> wrote: >Does anyone know how linoleic acid (the C18 omega 6 essential fatty acid) >evolved? This fat is high in seeds and nuts. >It is often said that the omega 3 essential fatty acid linolenic acid is >only made in chloroplasts. I'm not shure of your intention behind this thoughts. I've wondered too, why some food items, particularly some nuts are so exceptionally high in w-6 and low in w-3 EFAs (unfortunately for humans). I think obviously LA is easier to make for the plants as LNA but also less usable for some purposes. Should have something to do with the "electron clouds" which display at the bending positions (of unsaturation) in the chains. Plants may have less use for them. No nerves, no smooth, soft, permeable tissues. A big factor is certainly that LNA is easier suspect to deterioration (oxidation or other destruction), in heat and sunlight. At last that's one reason why in buyable food items they are found so seldom. But why on earth do flax seeds, nearly as the only ones, make so exceptionally much of this stuff? Is there a special need? Do they have some sort of superior protection? regards Amadeus S.