Nutritional Supplementation during Cancer Treatment: Is It Necessary, Safe and Helpful?A Narrative Review

Cancer (CA) occurs when cells divide out of control. CA cells usually tend to spread from the initial locus to the near and far tissues, the so-called metastasis. The cause of most cancers is unknown to date yet some factors including viruses, ionizing radiations and certain nutritional factors may promote genetic changes leading to malignant tumor growth. There are several treatment options for cancers including surgery, chemotherapy, radiotherapy and immunotherapy. Although most cancers are life threatening, CA treatments carry many side effects for the affected patient including fatigue, anorexia, hair loss, anemia, neuropathy, gastrointestinal problems like diarrhea or constipation, and weight loss mostly due to loss of lean body mass. As many patients under CA treatment are not able to have an adequate dietary intake, using nutritional supplements (NS) may seem a reasonable approach. Nevertheless, there is some evidence suggesting that some NS may promote CA cell growth and poor prognosis. Here, the most recent findings in this field along with our personal experience are discussed and some recommendations are made based on current evidence.