A study reported in the August 1, 2007 issue of the Journal of the National Cancer Institute concluded that men who consume more cruciferous vegetables, particularly broccoli and cauliflower, have a lower risk of aggressive prostate cancer. The cruciferous family of vegetables, which also includes cabbage, kale, and Brussels sprouts, has been associated in previous research with protection from colon, breast, prostate, thyroid, cervical, and other cancers, as well as with slower disease progression.
For the current study, Victoria Kirsh, PhD, of Cancer Care Ontario in Toronto and colleagues utilized data from 29,361 men participating in the Prostate, Lung, Colorectal and Ovarian Cancer Screening Trial. Over the 4.2 year average follow-up period, 1,338 men were diagnosed with prostate cancer, including 520 with aggressive disease. Dietary questionnaires completed by the participants were analyzed for the association of fruits and vegetables with prostate cancer risk.
While total fruit and vegetable intake was not found to be related to prostate cancer risk, higher intake of dark green as well as cruciferous vegetables was found to be associated with a lower risk of the disease, particularly that which was aggressive and had spread beyond the prostate. Broccoli and cauliflower had especially strong protective associations against aggressive and extraprostatic disease. Men whose intake of broccoli was greatest, at more than one serving per week, had a 45 percent lower risk of extraprostatic disease cancer than men whose intake was least, at less than once per month. Cauliflower was associated with an even greater benefit, with a 52 percent reduction in risk experienced by men who consumed the vegetable more than once per week. The gluocinsolate-derived compounds contained in cruciferous vegetables modify cancer risk by protecting cells from DNA damage, inducing apoptosis, influencing genetic expression, and inhibiting prostate cancer cell proliferation.
"Aggressive prostate cancer is biologically virulent and associated with poor prognosis. Therefore, if the association that we observed is ultimately found to be causal, a possible means to reduce the burden of this disease may be primary prevention through increased consumption of broccoli, cauliflower, and possibly spinach," the authors conclude.
Related Health Concern: Prostate Cancer
Besides laboratory testing, physical examination, and investigative procedures to rule out the presence of prostate cancer (PC) and other diseases, an action plan to prevent their development should be considered.
A dietary history of significant lycopene and/or strawberry consumption correlated with a lower risk of aggressive and extra-prostatic PC. The lycopene source that was found to be most significant in most epidemiologic studies was the tomato, in the form of tomato sauce, stewed tomatoes, and pizza. In one large-scale study involving 812 new cases of PC over the years 1986-1992 with matched controls, of the 46 vegetables and fruits or related products significantly associated with lower PC risk, three of the four identified were related to lycopenes--tomato sauce, tomatoes, and pizza. In this study, the combined intake of tomatoes, tomato sauce, tomato juice, and pizza (accounting for 82% of lycopene intake) was associated with a reduced risk of PC for consumption frequency greater than 10 versus less than 1.5 servings a week. Lycopene intake was also associated with a 53% reduced risk for advanced PC (Stages III and IV). The other nonlycopene product identified with significantly lower PC risk was strawberries.
The largest relevant dietary study, a prospective study in male health professionals, found that consumption of 2-4 servings of tomato sauce a week was associated with about a 35% risk reduction of total PC and a 50% reduction of advanced (extra-prostatic) PC. Tomato sauce was by far the strongest predictor of plasma lycopene levels in this study. These associations persisted in analyses controlling for fruit consumption, vegetable consumption, and olive oil use.