Men with early stage prostate cancer are often advised to increase their intake of vegetables to lower the risk for progression to more serious disease. But now a randomized trial has found that vegetables, whatever other health benefits they may confer, have no discernible effect on prostate cancer progression.
In a two-year study published in JAMA, researchers randomly divided 478 patients with biopsy-confirmed early stage prostate cancer into two groups. Men in the first group were enrolled in a behavioral counseling program, with each assigned a counselor who, with repeated telephone calls, encouraged them to eat at least seven daily servings of fruits and vegetables. The second were simply given written information about diet and prostate cancer.
Diet interviews and blood tests for carotenoid concentrations showed that compared with the controls, the intervention group consumed significantly more vegetables. They also ate less red meat and less fat.
But there was no difference between the groups in time to progression to higher grade tumors as measured by increases in prostate specific antigen levels or by repeated biopsy.