Food groups and colorectal cancer risk.

Most studies of diet and colorectal cancer have considered nutrients and micronutrients, but the role of foods or food groups remains open to debate. To elucidate the issue, we examined data from a case-control study conducted between 1992 and 1997 in the Swiss canton of Vaud. Cases were 223 patients (142 men, 81 women) with incident, histologically confirmed colon (n= 119) or rectal (n= 104) cancer (median age 63 years), linked with the Cancer Registry of the Swiss Canton of Vaud, and controls were 491 subjects (211 men, 280 women, median age 58 years) admitted to the same university hospital for a wide spectrum of acute non-neoplastic conditions unrelated to long-term modifications of diet. Odds ratios (OR) were obtained after allowance for age, sex, education, smoking, alcohol, body mass index, physical activity and total energy intake. Significant associations were observed for refined grain (OR = 1.32 for an increase of one serving per day), and red meat (OR = 1.54), pork and processed meat (OR = 1.27), alcohol (OR = 1.28), and significant protections for whole grain (OR = 0.85), raw (OR = 0.85) and cooked vegetables (OR = 0.69), citrus (OR = 0.86) and other fruits (OR = 0.85), and for coffee (OR = 0.73). Garlic was also protective (OR = 0.32 for the highest tertile of intake). These findings in a central European population support the hypothesis that a diet rich in refined grains and red meat increases the risk of colorectal cancer; they, therefore, support the recommendation to substitute whole grains for refined grain, to limit meat intake, and to increase fruit and vegetable consumption.