Role of Fatty Acids in the Resolution of Autoimmune and Inflammatory Diseases

The main role of fatty acids is focused on serving as major substrates for energy production; however, fatty acids are also involved in the formation of cellular structures as well as in the transmission of cellular signals. Among the multiple functions attributed to fatty acids are their anti-inflammatory properties. This important characteristic has been applied in the prevention, attenuation or treatment of inflammatory disorders. Based on the previous argument is obvious that several fatty acids (mainly n-3 polyunsaturated or n-9 monounsaturated fatty acids) are capable of modulating immune system functions. These fatty acids may alter immune response through different mechanisms such as alteration of membrane fluidity, eicosanoid synthesis, oxidative stress, regulation of gene expression, apoptosis or modulation of gastrointestinal microbiota. Early studies in Greenland Eskimos determined the low prevalence of inflammatory disorders in this population (Kromann et al., 1980). Despite their beneficial effects in the reduction of inflammatory diseases, other studies have demonstrated that the administration of diets containing long-chain n-3 polyunsaturated fatty acids may contribute, at least in part, to the reduction of host resistance against infectious agents. In fact, epidemiological investigations described a high incidence of tuberculosis in native Eskimos (Kaplan et al., 1972), who consume a great amount of n-3 polyunsaturated fatty acids. These data are clearly illustrative of the potential action of certain fatty acids on the inflammatory response, and of the consequences derived from an excessive immunosuppression. It is obvious that these fatty acids contained in the diets produce an immune status able to ameliorate inflammatory conditions. Indeed, a growing number of studies using healthy human subjects as well as animal disease models have undoubtedly demonstrated dietary fish oil or olive oil to possess anti-inflammatory properties. For this reason, polyunsaturated or monounsaturated fatty acids have showed beneficial effects in numerous inflammatory diseases characterized by a overactivation of immune system such as asthma (childhood and adult), multiple sclerosis, glomerulonephritis, inflammatory bowel disease (Crohn’s disease, ulcerative colitis) and rheumatoid arthritis . Here, we summarize the involvement of fatty acids as anti-inflammatory agents and the action that these fatty acids contained in the human or animal diets exert on the prevention or treatment of autoimmune diseases.