Role of nutrition in preventing cancer.

OBJECTIVE To summarize the evidence linking dietary habits to the incidence of several types of cancer with special emphasis on the chemoprotective properties of foods that originate from plants. QUALITY OF EVIDENCE A large body of epidemiologic, animal, and laboratory literature indicates that as many as 30% of all cancer cases are linked to poor dietary habits. The proportion reaches 70% for cancers of the gastrointestinal tract. MAIN MESSAGE Studies have consistently linked abundant consumption of plant-based food to a substantial reduction in risk of developing various cancers. Laboratory studies show that this chemopreventive effect is related to the high levels of numerous phytochemicals in this food. These phytochemicals interfere with several cellular processes involved in the progression of cancer and also with inflammatory processes that foster development of cancer. CONCLUSION Dietary factors play an important role in the high incidence of several types of cancer in Canada. Modification of dietary habits to include daily intake of plant-based food containing anticancer and anti-inflammatory phytochemicals thus represents a promising approach to preventing the development of cancer.