[Diet and autoimmunity]

New data emphasize the importance of nutritional factors in autoimmune diseases. Dietary alterations can be linked to autoimmune disorders as a specific pathogenetic mechanism and also for the malnutrition conditions frequently documented in these patients. The precise function of different nutrients is not completely known as they can be primary pathogenetic agents or causes of acute reacerbations or, finally, simply accompanying phenomena. It is also difficult to modify the intake of a single dietary component and to clarify its metabolic importance for the complexity of metabolic events in the human body and for the possible appearance of cascade-mechanisms. In lipid metabolism the multiple interactions between fatty acids, prostaglandins and leukotrienes are linked to alterations in inflammatory parameters. The exact role of modifications of proteins or of a single amino acid on immune function, also for the possible interference in protein restricted diet of the caloric component, is still unknown. Trace elements and vitamins are certainly important for the control of inflammation and of susceptibility in infections, albeit their role is not clear. More studies are necessary to clarify the link between dietary component and autoimmune diseases. However, study in experimental models and in human Systemic Lupus Erythematosus and Rheumatoid Arthritis demonstrated that a good nutritional homeostasis can contribute to decrease the severity of these disorders and to modify the clinical course with a physiological treatment that is free of side effects.