Plant foods, antioxidants, and prostate cancer risk: Findings from case-control studies in Canada

Epidemiological data on most cancer sites suggest that consumption of plant foods, which contain high levels of antioxidants, might slow or prevent th e appearance of cancer. We used data from three case-control studies to tes t this hypothesis. The total study population consisted of 617 incident cas es of prostate cancer and 636 population controls from Ontario, Quebec, and British Columbia. Dietary information was collected by an in-person interv iew with a detailed quantitative dietary history. Unconditional logistic re gression analyses were performed to estimate odds ratios (ORs) and 95% conf idence intervals (Cls). A decreasing, statistically significant association was found with increasing intakes of green vegetables (OR = 0.54, 95% CI = 0.40-0.71 for 4th quartile), tomatoes (OR = 0.64, 95% CI = 0.45-091), bean s/lentils/nuts (OR = 0.69, 95% CI = 0.53-0.91), and cruciferous vegetables (OR = 0.69, 95% CI = 0.52-091 for 3rd quartile). Higher intakes of fruit we re associated with higher ORs (OR = 1.51, 95% CI = 1.14-2.01 for 4th quarti le), an effect that was seen for total fruit and citrus fruit, as well as f or all other noncitrus fruits. Among the grains, refined-grain bread intake was associated with a decrease in risk (OR = 0.65 for 4th quartile), where as whole-grain breakfast cereals were associated with a higher risk for pro state cancer. Of all the antioxidant nutrients studied the ORs were higher with higher intakes of cryptoxanthin (OR = 1.44, 95% CI = 1.09-1.89 for 4th quartile). Exposure to certain dietary components of plant origin, which a re potentially modifiable, indicates the theoretical scope for reducing the risk from prostate cancer Future experimental studies or trials are warran ted for further understanding.