Effects of supplemental dietary arginine, canola oil, and trace elements on cellular immune function in critically injured patients.

Dietary nutrients may have pharmacological value in modulating the immune system. We studied the effects of two enteral diets, which differed in their content of arginine, fat source, and select trace elements, on immune function in critically injured patients. Leukocytes were isolated from healthy volunteers and severely injured (ISS > 13) patients on the first, sixth, and tenth day of receiving either a standard diet or experimental diet. Monocytes were assayed for tumor necrosis factor, procoagulant activity, and prostaglandin E2 following endotoxin exposure. Neutrophil oxidant production and lymphocyte blastogenesis was assessed. Leukocyte function was uniformly depressed compared to normal patients on day 1. The response of leukocytes from patients receiving experimental diet improved or "normalized" by day 6, while remaining depressed in patients receiving standard diet. Dietary nutrient modification can effect cellular immune responses to inflammatory stimuli in severely injured patients.