Objectives: To evaluate the feasibility of implementing a diet-based intervention in men with prostate cancer.
Methods: Seventy-four men aged 50 to 80 years with biopsy-proven adenocarcinoma of the prostate were randomized to receive either telephone-based dietary counseling or standardized, written nutritional information. Telephone dietary counseling targets included increased intakes of vegetables (particularly cruciferous vegetables and tomato products), whole grains, and beans/legumes. Dietary intakes and plasma carotenoid levels were assessed at baseline and at 6 months' follow-up.
Results: In the intervention arm, mean daily intakes of total vegetables, crucifers, tomato products, and beans/legumes increased by 76%, 143%, 292%, and 95%, respectively, whereas fat intake decreased by 12% (P = 0.02). In the control arm, there were no significant changes in mean intakes of total vegetables, tomato products, crucifers, beans/legumes, or fat. Similarly, in the intervention arm, mean plasma levels of alpha-carotene, beta-carotene, lutein, lycopene, and total carotenoids increased by 33%, 36%, 19%, 30%, and 26%, respectively (P <0.05). In the control arm, there were no significant changes in plasma levels of alpha- or beta-carotene, lutein, lycopene, or total carotenoids.
Conclusions: Telephone-based dietary counseling increases vegetable intake, decreases fat intake, and significantly increases plasma levels of potentially anticarcinogenic carotenoids in men with prostate cancer. These data support the feasibility of implementing clinical trials of dietary intervention in men with prostate cancer.