The optimalisation of the health status of patients scheduled for major surgery has been considered to be the most important point of perioperative care, and nutritional intervention has been perceived a key point of that intervention. Immunomodulating diets were thought to reduce cmplications, hoever recent studies put that opnion in doubt. This study was designed to assess the actual clinical significance of oral immunonutrition.

The optimalisation of the health status of patients scheduled for major surgery has been considered to be the most important point of perioperative care, and nutritional intervention has been perceived a key point of that intervention. Italian studies followed by metanalyses demonstrated the superiority of immunomodulating diets (IM) over any other preoperative nutrition, hence the surgical guidelines for enteral nutrition published by European Society for Clinical Nutrition and Metabolism (ESPEN) in 2006 recommended to use IM for 7-14 days preoperatively in all patients undergoing major surgeries. Some authors questioned IM by showing no benefit of IM over standard enteral nutrition. Other authors observed similar results.The debate was far from being over - in 2015 a new metanalysis stated that perioperative enteral nutrition is the best option for managing clinical status of patients who underwent selective surgery for gastrointestinal cancer. One year later, ESPEN changed its surgical recommendations and advised to use IM preoperatively in malnourished and perioperatively in well-nourished patients. American recommendations remained unchanged and, according to them, it is advised to use IM preoperatively in all surgical patients, however, high-protein nutrition could also be an beneficial option.

To address those doubts and to assess the actual clinical significance of oral immunonutrition, a randomized, two center, prospective clinical trial was conducted.

Inclusion Criteria:

• no sign of malnutrition (defined as one of the following unintentional weight loss by at least 10% or body mass index (BMI) < 18),
• good general status (Karnofsky Performance Index > 80,
• Eastern Cooperative Oncology Group (ECOG) grade 0 or 1);
• no confirmed neoplastic dissemination no severe concomitant disease (heart, lung, kidney, liver failure, chronic obstructive pulmonary disease [COPD], coronary aortic bypass graft [CABG], etc.),
• no history of known allergies or drug intolerance to analyzed substances.

Exclusion Criteria:

• Patients malnourished or with metastatic disease,
• pregnant,
• in poor general status (Karnofsky <80, Eastern Cooperative Oncology Group (ECOG) > 1),
• recent history of severe heart, lung, kidney or liver failure,
• history of allergies or drug intolerance

12 months

any health professional

The physician is unaware of the type of the intervention. The type of intervention is given by the independent person to dietitian instructing the patient how to use the product.