[Cancer and nutrition - a paradigma shift]

Substantial international differences in the prevalence of cancer disease suppose that nutrition may be an important factor in the development of cancer. Many experts believe, that nutritional factors may contribute up to 35 % to the development of malignant tumors. Many patients have lost substantial body weight already at the time of the diagnosis of the disease as consequence of undernutrition and malnutrition, respectively. During the course of the disease the nutritional status often is deteriorating further. Caused by both the cancer disease itself and the treatment, loss of appetite, changes in taste, nausea and vomiting may additionally contribute to undernutrition. Undernutrition is a relevant factor for the outcome of the disease and for the tolerance of the treatment as well. Therefore, supporting the heavily impaired patients in nutritional intake is of paramount importance and an urgent task for physicians and nurses. In view of physiology, pathophysiology, genetics and molecular biology, metabolic processes in cancer are highly complex regulated and there is increasing evidence that a diet rich in fat and protein is favourable. This, however, implies a paradigma shift away from the "healthy" balanced diet rich in fruit, vegetable and complex carbohydrates. So far, the evidence based data of this new concept is, however, a controversial issue.