Modulation of inflammation and immunity by omega-3 fatty acids: a possible role for prevention and to halt disease progression in autoimmune, viral, and age-related disorders.

Omega-3 polyunsaturated fatty acids (PUFA) have demonstrated anti-inflammatory properties, while Omega-6 have pro-inflammatory effects, and the balance between the two is an important aspect of healthy nutrition. Over the last 30 years, however, the Western diet has shifted largely from Omega-3 to Omega-6 consumption. Uncontrolled aberrant and chronic inflammation is a leading component of many common diseases, including arthritis, cardiovascular diseases, neurodegenerative diseases, cancer, obesity, autoimmune diseases, and infective diseases. Eicosanoids derived from Omega-6 participate in the inflammatory process, while Omega-3 PUFA have the opposite effect. Many favorable effects of Omega-3 are believed to result from their anti-inflammatory properties, but eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) also have inhibitory effects on immune cells and reduce proinflammatory cytokine release. All these mechanisms can be beneficial in autoimmunity. No effective preventions or definite cures for autoimmune diseases are yet known because pathophysiology is also unclear. Omega-3 fatty acid supplementation is associated with a significant reduction in disease activity in several autoimmune diseases, like type 1 diabetes (T1D), rheumatoid arthritis (RA), systemic lupus erythematosus (SLE), and multiple sclerosis (MS). Studies of viral diseases, including COVID-19, show improvement in symptom severity, recovery prognosis, and probability of survival with the use of Omega-3. Finally, the evidence of the beneficial effect of Omega-3 on metabolic diseases associated with aging is persuasive; various studies have demonstrated that their consumption improves lipids, fatty liver disease, obesity, cognitive function, and cardiovascular complications of chronic kidney disease (CKD). Omega-3 PUFA have also been shown to support an anti-inflammatory effect in older age and to have favorable effects on age-related disease's complications, frailty, and mortality. A healthy Omega-6/3 PUFA ratio should be targeted for the modulation of low-grade inflammation, as well as for the prevention of immune dysregulation and complications of uncontrolled inflammation triggered by infections, development, and progression of autoimmune disorders, and the consequences of oxidative stress due to aging. There is still a need for randomized clinical studies to validate current evidence supporting supplementation with correct doses of Omega-3 PUFA in autoimmune and chronic disease prevention.