Afterwards the patients are going to be divided into one group who will receive nutrition support using immunonutrition for the next 8 weeks while the second one will continue with their nutrition support using routine sipping support with no immunonutrition. According to our hypothesis oxidative stress parameters will improve in the group of patients on immunonutrition comparing to the other group. Afterwards the patients will change their nutrition support for another 8 weeks. The patients who took immunonutrition in the first half of study will switch back to routine sipping support and contrary the patients who were in the first part of study on routine sipping will take immunonutrition. After the end of this period of study we expect the return of oxidative stress parameters to the baseline values in the group of patients who took immunonutrition in the first half of study but who were returned to routine nutrition support and contrary the improvement of oxidative stress parameters in the patients who started to take immunonutrition in the second half of study.