**Abstract**

The roles of diet and environment on health have been known since ancient times. Cancer is both a genetic and an epigenetic disease and a complex interplay mechanism of genetic and environmental factors composed of multiple stages in which gene expression, protein and metabolite function operate synchronically. Disruption of epigenetic processes results in life-threatening diseases, in particular, cancer. Epigenetics involves altered gene expression without any change of nucleotide sequences, such as DNA methylation, histone modifications and non-coding RNAs in the regulation of genome. According to current studies, cancer is preventable with appropriate or balanced food and nutrition, in some cases. Nutrient intake is an environmental factor, and dietary components play an importent role in both cancer development and prevention. Due to epigenetic events induce changes in DNA and thus influencing over all gene expression in response to the food components, bioactive compounds and phytochemicals as potent antioxidants and cancer preventive agents have important roles in human diet. Several dietray components can alter cancer cell behavior and cancer risk by influencing key pathways and steps in carcinogenesis, including signaling, apoptosis, differentiation, or inflammation. To date, multiple biologically active food components are strongly suggested to have protective potential against cancer formation, such as methyl-group donors, fatty acids, phytochemicals, flavonoids, isothiocyanates, etc. Diet considered as a source of either carcinogens that are present in certain foods or acting in a protective manner such as vitamins, antioxidants, detoxifying substances, chelating agents etc. Thus, dietary phytochemicals as epigenetic modifiers in cancer and effects of dietary phytochemicals on gene expression and signaling pathways have been widely studied in cancer. In this chapter, current knowledge on interactions between cancer metabolism, epigenetic gene regulation, and how both processes are affected by dietary components are summerized. A comprehensive overview of natural compounds with epigenetic activity on tumorogenesis mechanisms by which natural compounds alter the cancer epigenome is provided. Studies made in epigenetics and cancer research demonstrated that genetic and epigenetic mechanisms are not separate events in cancer; they influence each other during carcinogenesis, highlighting plant-derived anticancer compounds with epigenetic mechanisms of action, and potential use in epigenetic therapy. Recent investigations

involving epigenetic modulations suggest that diet rich in phytochemicals not only reduce the risk of developing cancer, but also affect the treatment outcome.

**Keywords:** diet, cancer, epi-drugs, epigenetic modulation, phytochemicals
