University of Southampton, Southampton, Reino Unido
Inflammation contributes to a range of human diseases including common age-related conditions (1). Lipids and their fatty acid components play key roles in regulation of inflammatory processes. Different fatty acid classes, and within the classes, different individual fatty acids have different effects. This is because they act through both general and specific molecular and cellular mechanisms. Consequently one fatty acid, or class of fatty acids, may oppose the action(s) of another. Higher saturated fatty acid intake and status is associated with higher levels of inflammatory markers in the bloodstream (2) and some medium and long chain saturated fatty acids have been demonstrated to directly activate inflammation via tolllike receptor (TLR) 4. The omega-6 fatty acid arachidonic acid is the precursor to eicosanoids like prostaglandin E2 and 4 series leukotrienes that are directly involved in inflammatory processes (3). Omega-3 fatty acids (O3FA) often oppose the different actions of saturated and omega-6 polyunsaturated fatty acids. Among the O3FA, the most biologically active are eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are found in oily fish, fish oil supplements and a small number of pharmaceutical grade preparations. They are able to reduce inflammatory responses. Key effects of EPA and DHA include reduced production of eicosanoids from arachidonic acid; increased production of anti-inflammatory and inflammation resolving mediators (resolvins, protectins and maresins); altered activity of several transcription factors (NFkB, AP-1, PPARα, PPARα) so acting to reduce production of pro-inflammatory chemicals; and signalling through GPR120 in inflammatory cells and adipocytes (3). Through these molecular and cellular actions, O3FA counter several effects of saturated and omega-6 polyunsaturated fatty acids on inflammation. The resulting antiinflammatory effects may be linked with improved health and well-being (4). References 1.Calder, P.C., Albers, R., Antoine, J.M., Blum, S., Bourdet-Sicard, R., Ferns, G.A., Folkerts, G., Friedmann, P.S., Frost, G.S., Guarner, F., Løvik, M., Macfarlane, S., Meyer, P.D., M’Rabet, L., Serafini, M., van Eden, W., van Loo, J., Vas Dias, W., Vidry, S., Winklhofer- Roob, B.M. and Zhao, J., Inflammatory disease processes and interactions with nutrition. British J Nutr 2009;101:S1- S45. 2.Calder, P.C., Ahluwalia, N., Brouns, F., Buetler, T., Clement, K., Cunningham, K., Esposito, K., Jonsson, L.S., Kolb, H., Lansink, M., Marcos, A., Margioris, A., Matusheski, N., Nordmann, H., O’Brien, J., Pugliese, G., Rizkalla, S., Schalkwijk, C., Tuomilehto, J., Warnberg, J., Watzl, B. and Winklhofer-Roob. B.M., Dietary factors and low-grade inflammation in relation to overweight and obesity. British J Nutr 2011;106 (Suppl. 3):S5-S78. 3. Calder, P.C., Marine omega-3 fatty acids and inflammatory processes: Effects, mechanisms and clinical relevance. Biochimica et Biophysica Acta 2015;1851:469-484. 4. Calder, P.C., Very long chain omega-3 (n-3) fatty acids and human health. Europ J Lipid Science and Technology 2014;116:1280-1300.