Immunonutrition in clinical practice: what is the current evidence?

The clinical trials of immunonutrition that we have undertaken have often been small, single centre studies. They have often been of limited statistical power and have often included patients with a variety of underlying disease states and at different points in the disease process. Three meta-analysis and a consensus statement in conjunction with a systematic review, have been performed in an attempt to overcome many of these limitations and understand further the clinical place for immunonutrition. However, there are still many questions regarding the place of immunonutrition in clinical practice that we still do not understand or have definitive answers to. For example, do we really know what is the optimal combination of nutrients and in what quantities they should be provided? Do we understand any potential interactions that might occur between these nutrients? What is the effect of the patients nutritional state? When and for how long should immunonutrition provided? What is the impact of the patients' underlying disease process and how does this interact with the provision of immunonutrition? At the present time whilst there is some indication and evidence as to which patients might benefit most, and as to those who may not benefit or even suffer detrimental effects from immunonutrition, we still can not answer these questions with any definitive authority. It is essential now that we undertake large well designed, well controlled multicentre studies with adequate statistical power to answer these questions. The indications are that immunonutrition has the potential to help patients but its place must be more clearly defined before its widespread acceptance into clinical practice is based on sound scientific evidence.