Vegetable, Fruit Intake May Help Protect Men From Colorectal Cancer
The intake of vegetables and fruit is inversely related to colorectal cancer risk among men but not among women, and the association appears stronger for colon cancer than for rectal cancer, according to the results of a large prospective study reported in the September issue of the American Journal of Nutrition.
“It is uncertain whether or not vegetables, fruit, or grains protect against colorectal cancer,” write Abraham M.Y. Nomura, MD, PhD, from the University of Hawaii in Honolulu, and colleagues. “These plant foods contain potential anticarcinogenic agents, such as antioxidants, flavonoids, isothiocyanates, phenols, and protease inhibitors.”
The goal of this study was to determine the association of vegetable, fruit, and grain intakes with risk for colorectal cancer in the Multiethnic Cohort Study. Between 1993 and 1996, 85,903 men and 105,108 women completed a quantitative food frequency questionnaire inquiring about intake of 180 foods and beverages.
After an average follow-up of 7.3 years, 1138 of the men and 972 of the women were diagnosed with colorectal cancer. Relative risks for colorectal cancer, after multivariate adjustment for energy intake, dietary, and nondietary variables, were calculated using Cox proportional hazards models.
In the highest quintile of intake among men, adjusted relative risks were 0.74 for vegetables and fruit combined (95% confidence interval [CI], 0.59 – 0.93; P for trend = .02); 0.80 for fruit alone (95% CI, 0.64 – 0.99; P for trend =.09), and 0.85 for vegetables alone (95% CI, 0.69 – 1.05; P for trend = .05). Among men, the inverse associations were stronger for colon than for rectal cancer.
None of the associations with vegetables, fruit, or vegetables and fruit combined were significant in women, and grain intake was not associated with colorectal cancer for either men or women.
“The intake of vegetables and fruit was inversely related to colorectal cancer risk among men but not among women,” the study authors write.
Limitations of this study include omission of many foods by food frequency questionnaires and possible confounding by measured and unmeasured factors.
“The association appeared consistent across the different ethnic groups in the study and was stronger for colon cancer,” the study authors conclude. “Separation according to the different sources of vegetables and fruit did not identify specific food groups that accounted for the association.”

