William A. Altemeier lecture. Nutrition and infection. New perspectives for an old problem.

Dietary variables have an important influence on immunologic responses, resistance to infection, and survival. Injury and infection can markedly alter dietary requirements and the diet can markedly influence the body's response to injury and/or infection. Experiments are described that show that diets following burn injury required more energy intake, more protein (22% vs 15%), and less fat (10% vs 50%) for optimal support. Oral administration (vs intravenous) improved outcome, especially when given immediately after the burn, which prevented the hypermetabolic response. Crystalline amino acids in the enteral diet had an adverse effect compared with intact protein. The type of lipid in the diet after burn injury strongly influenced immunologic and inflammatory responses, with eicosapentaenoic acid being beneficial and linoleic acid being harmful. Dietary manipulation in surgical disease, especially infection, will have an increasingly important role in outcome as these complex interactions are dissected and understood.