Omega-3 essential polyunsaturated fatty acids have distinct chemical structures and physiologic functions that distinguish them from other families of essential fatty acids. Often lacking in Western diets, omega-3 fatty acids compete with other fatty acids in the body for cyclooxygenase (COX) and lipoxygenase (LOX) enzyme metabolism, incorporation into cell membranes, and the synthesis of lipid mediators. The long-chain omega-3 fatty acids, eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are almost exclusively marine-derived and act together to influence membrane fluidity and signal transduction pathways.
EPA and DHA are abundantly enriched in the retina, brain, and heart tissues. Each have preferential distribution within the phospholipid bilayer of cell membranes and have been shown to exert unique biological actions.
Humans have limited capacity to endogenously produce EPA and DHA; therefore they are considered essential fatty acids. Dietary supplementation of EPA and DHA is an effective way to increase intake of these essential fatty acids.