Dietary lipids, eicosanoids, and the immune system

The body possesses an array of mechanisms which protect against foreign agents that can cause sickness, infections, pathogens, and sepsis. These include the innate protective systems, e.g., physical barriers (skin, mucosal membranes), chemical barriers (pH, enzymes, lysozymes, transferrin), and cellular protection (macrophages, PMN cells), and the sophisticated acquired immunity system which includes cellular (T cells, macrophages) and humoral (B cells, antibodies) mechanisms. The nutritional status of the subject greatly affects the efficacy of each of these systems to minimize the incidence and severity of infections. In malnutrition the capacity to counteract infection is impaired because of fewer and less potent cells, inadequate immunoglobulin (Ig) G production, less complement proteins and interleukins, and attenuated microbiocidal capacity of macrophages and neutrophils. More information concerning the effects of nutrients is important for both etiological assessment and therapeutic considerations in pathophysiological states.