Rethinking lipid mediators

Abstract

One of the characteristics of the modern western diet is the imbalance of the two essential fatty acids, the omega-6 and the omega-3 fatty acids (figure). The most important omega-6 fatty acid is arachidonic acid (20:4n 6); the important omega-3 fatty acids are eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3). Today's western diet has a ratio of omega-6 to omega-3 fatty acids of 15:1, when data suggest that human beings evolved, and lived for most of their existence, on a ratio close to 1:1. Changes in eating habits and in agriculture within the past 100–200 years are the main cause of this changed ratio. 1 Simopoulos AP The importance of the ratio of omega-6/omega-3 essential fatty acids. Biomed Pharmacother. 2002; 56: 365-379 Crossref PubMed Scopus (2561) Google Scholar This shift might be important because these fatty acids are the precursors of the eicosanoid lipid mediators: the prostaglandins (PGs) and leukotrienes, lipoxins, epoxyprostanoids and isoprostanes. COX=cyclo-oxygenases, LO=lipoxygenases. Prostaglandins (PG), thromboxanes (TX), leukotrienes (LT), lipoxins (LX), resolvins (Rv), docosatrienes (DT), and aspirin-triggered lipoxins (ATLs) are shown with their respective abbreviations. Underlined are those mediators for which specific receptors have been identified.