CHAPTER 17: Nutrition and Colorectal Cancer Prevention

Colorectal carcinoma (CRC) is the third most common cancer in men and the second most common in women, but its age-standardised incidence is much higher in countries with prosperous urbanised populations than in less developed countries. Early studies of CRC suggested that diets based on unprocessed plant foods were protective, and that higher consumption of meat and animal products increased the risk. These findings have been largely confirmed. Recommendations to consume higher levels of dietary fibre and less fresh and processed meat are included in the dietary guidelines of most countries seeking to reduce the risk of CRC and other non-communicable diseases. The mechanisms underlying these associations of CRC with nutrition are still only poorly understood, but metabolic abnormalities and chronic systemic inflammation probably increase the likelihood of CRC in later life. If the vulnerability of the colorectal mucosa to neoplasia is increased by dietary and metabolic factors acting over a lifetime, effective preventive measures need to begin early in life and should be based on a deeper mechanistic understanding of colorectal carcinogenesis. To address these questions, we require better molecular biomarkers of early carcinogenesis and novel experimental strategies, applied across the lifespan, and in high and low risk populations.