Colorectal cancer (CRC) is a serious epidemiological problem in developed countries due to the growing incidence of CRC and low percentage of 5-year survival of patients with CRC. A large proportion of CRCs (approx. 70%) are sporadic with the aetiology remaining unexplained. Risk of CRC is mainly modulated by individual susceptibility to cancer development, shaped by the interplay between genetic and environmental factors. At present it is widely accepted that low penetration gene polymorphisms (e.g. DNA repair genes) are the main genetic factor in modulation of individual susceptibility. However, diet is considered as the most important environmental factor (over-consumption of omega-6 fats and red meat, diet poor in fruits and vegetables).