Total parenteral nutrition and immune system activity: a review

Malnutrition has been associated with immunosuppression, reduced host defenses, and increased incidence of infections and mortality. Improvement of nutritional status through various nutritional support regimens may restore immunocompetence and consequently reduce the rate and severity of infections in hospitalized patients. However, several investigators, exploring the effect of total parenteral nutrition (TPN) on the immune system, have suggested that TPN may adversely affect immune function. During the past 20 yr special interest was given to the possible immunosuppressive effect of parenteral fat emulsions and conflicting reports have been published. This review focuses on the consequences of TPN on immune response and investigates whether there might be a link between the nutrients, the immune system, and possibly the central nervous system, which also seems to affect immune response.