Total parenteral nutrition and enteral nutrition in diabetes.

A quarter or more of critically ill patients are likely to have carbohydrate intolerance or frank diabetes, either pre-existing or secondary to the stress of illness. Those patients who require parenteral nutrition should be treated using regimens similar to those used in nondiabetic patients, along with sufficient insulin (given by separate infusion) to maintain near-normal glycaemia. The role of novel substrates in diabetes remains to be established. In patients who require enteral nutrition, there is accumulating evidence that high-fat (as monounsaturated fatty acid) formulations achieve better overall metabolic control than conventional high-carbohydrate preparations. In view of the fact that macrovascular disease is the major cause of morbidity and mortality in type 2 diabetes in particular, and the fact that the risk of macrovascular complications is relatively unaffected by glycaemic control, the improved lipid and haemostatic profile achieved with preparations that are high in monounsaturated fatty acids is of particular importance in patients on long-term nutritional support.