Diet and colorectal cancer risk: current views.

Large bowel cancer (CRC) is amongst the most common cancers in North America, Australasia and western Europe. The major risk factors of CRC are genetic and dietary. Evidence regarding genetic polymorphisms which may influence the metabolism of nutrients thought to be important in the aetiology of CRC and colorectal adenomatous polyps is discussed. At present, the strongest evidence of genenutrient interaction in relation to CRC is for folate and genetic variants associated with differences in metabolism of folate. Significant trends of increasing CRC risk with increasing intake emerged for total energy, bread and pasta, cakes and desserts, and refined sugar have been observed in recent Italian studies. Most vegetables, including pulses, were inversely associated with CRC. Among macronutrients, a high intake of starch and saturated fat seemed to lead to an increased risk of cancer. High intakes of polyunsaturated fatty acids (chiefly derived from olive oil and seed oils) showed a marginal inverse association with CRC. In the present paper the relation between meat consumption and cancer risk is reviewed showing that there is little evidence to support this relationship.