The essential fatty acids omega-3 and omega-6 are transformed in the body into hormones called eicosanoids, e.g. prostaglandin is an eicosanoid. They all have 20 carbon atoms, and the name comes from the Greek word eikos which means 20. The Nobel Prize for Medicin was in 1982 given to Sune Bergström, Bengt Samuelsson and John Vane for their research about eicosanoids. The first eicosanoid (prostaglandin) was discovered in 1936 by Ulf von Euler.
Dr. Barry Sears calls the eicosanoids powerful super hormones. They control other hormones and practically all important functions in the body, e.g. the central nervous system and the immune system. Thus, they are very important for good health and well-being. There are both good and bad eicosanoids, and a good balance between them is achieved by eating food that contains both omega-3 and omega-6.
There are also other things that determine the balance between good and bad eicosanoids, such as the hormones insulin and glucagon. A diet consisting of a high amount of carbohydrates - especially fast carbohydrates - creates too much insulin in the body. This means that there will be an over-production of bad eicosanoids. A zone-favorable diet means less carbohydrates, this will produce more glucagon and good eicosanoids which enhances health. The fatty acid EPA is an important fat since more good eicosanoids will be produced. A high consumption of the short-chain fatty acid ALA can interfere with the production of eicosanoids, according to researcher Barry Sears, and the same is true for trans fatty acids.
Barry Sears explains in his book "The Zone" why both good and bad eicosanoids are needed in the body. The good ones prevent the blood from clumping, which lowers the risk for blood clots. However, when you bleed, the bad eicosanoids are needed in order for the blood platelets to aggregate and stop the bleeding. This is why the balance between them is important, since they are both needed in the body.
There are inbalances that lead to disease, inbalance between insulin and glucagon, good and bad eicosanoids, omega-3 and omega-6, and carbohydrates, proteins and fat. If you eat healthy the levels are adjusted automatically. Read more about eicosanoids and why fast carbs are bad for your health in the book "The Zone" by Barry Sears.