Omega-3 polyunsaturated fatty acids and health

There is mounting evidence that long-chain omega 3 (n-3) polyunsaturated fatty acids (PUFAs) have many health benets. These long-chain n-3 PUFAs include alpha-linolenic acid (ALA; 18:3n-3 or 18:3 Δ9,12,15), eicosapentaenoic acid (EPA; 20:5n-3 or 20:5 Δ5,8,11,14,17), docosapentaenoic acid (DPA; 22:5n-3 or 22:5 Δ7,10,13,16,19), and docosahexaenoic acid (DHA; 22:6n-3 or 22:6 Δ4,7,10,13,16,19). Their health benets appear to be associated with several different aspects, including their structure, their interactions with proteins that alter gene expression, and their unique metabolic fates. Structurally, when long-chain n-3 PUFAs are incorporated into cell membranes, they increase membrane uidity, thereby inuencing cell function. For example, higher n-3 PUFA content in neuronal membranes has been shown to improve neuron function [1]. Besides affecting membrane uidity, these fatty acids can also inuence the structure and function of proteins embedded in the phospholipid bilayer [2]. As mediators of cell sensors and receptors (e.g., G protein-coupled receptor 120 [3]), long-chain n-3 PUFAs also have a major impact on gene expression [4]. But perhaps the most studied aspect of long-chain n-3 PUFA relates to their metabolic fates. These fatty acids enter biochemical pathways that produce anti-inammatory compounds (Figure 23.1); in turn, these anti-inammatory agents decrease the risk of chronic diseases [5].