Omega-3 fatty acids and inflammation: Relevance to public health and patient outcomes

Abstract: Inflammation is a normal part of the immune response but should be self-limiting. Excessive or unresolved inflammation is linked to tissue damage, pathology and ill health. Prostaglandins and leukotrienes produced from the n-6 fatty acid arachidonic acid are involved in inflammation and are generally regarded as pro-inflammatory. The marine-derived omega-3 (n-3) fatty acids EPA and DHA possess a range of anti-inflammatory actions. Increasing the content of EPA and DHA in the membranes of cells involved in inflammation has effects on the physical nature of the membranes and on the formation of signalling platforms called lipid rafts. EPA and DHA interfere with arachidonic acid metabolism which yields prostaglandins and leukotrienes involved in inflammation. In turn, EPA gives rise to weak (i.e. less inflammatory) analogues and both EPA and DHA are substrates for the synthesis of specialised pro-resolving mediators. EPA and DHA result in altered patterns of gene expression and of protein production. The net result is decreased production of inflammatory cytokines, chemokines, adhesion molecules, proteases and enzymes. The anti-inflammatory and inflammation-resolving effects of EPA and DHA are relevant to both prevention and treatment of human diseases that have an obvious inflammatory component. This has been widely studied in rheumatoid arthritis where there is good evidence that high doses of EPA +DHA reduce pain and other symptoms. Anti-inflammatory effects of EPA and DHA are also relevant to obesity and to diseases of aging including atherosclerosis, type-2 diabetes, cognitive decline, sarcopenia ad some cancers. Increased intake of EPA and DHA should be encouraged to support optimal heath across the life course.