Patients who are diagnosed with prostate cancer were assigned to eat seven or more servings of vegetables and fruits every day, but they did not experience any decrease in their risk for progression of their disease, according to the study published in JAMA.
Dr. James Mohler, the co-author of the study and a professor of oncology with Roswell Park's department of urology stated that the most common question that he receives from men on active surveillance is whether they can decrease the chances that they will need treatment for prostate cancer by changing their diet.
Experts now have good evidence that a diet rich in vegetables and fruits and light on red meat is not likely to impact the need for treatment. But the study does not give justification for eating anything that the patient wants either. The overall health benefits of a diet that is relatively low in fat and rich in vegetables, fruits, and healthy grains are well-established.
Eating vegetables does not affect prostate cancer
The clinical guidelines for prostate cancer have promoted diets that are high in micronutrient-enriched vegetables. But the evidence does not support whether this kind of diet decreases prostate cancer progression or death.
In the MEAL study or Men's Eating and Living study, 478 men diagnosed with early-stage prostate adenocarcinoma, aged 50 to 80 years old, were enrolled across 91 sites in active surveillance programs. The program was comprised of those who deferred immediate treatment until their disease advanced.
In the study, the patients were randomized to a control group that got written information about their diet and prostate cancer or to a telephone counseling behavioral intervention program that encouraged them to eat foods that are high in carotenoids. Such foods include carrots, leafy greens and tomatoes, and cruciferous vegetables like cabbage and broccoli.
Lead study investigator Dr. J. Kellogg Parsons, from the University of California San Diego School of Medicine and Moores Cancer Center professor of urology said that they have designed a simple and inexpensive program that proved that they could change the diet of people for the better. They hoped that through nutrition they could alter disease outcomes and then use those data to create a network of diet counselors to help men with prostate cancer eat more vegetables.
After the patients were monitored for two years, there were around 245 progression events and four deaths during the whole study. There was no difference between arms in time to progression or in the total number of patients who went for active treatment.
Parsons also said that these data that they've gathered indicate that, despite prevailing scientific and public opinion, eating more vegetables will not alter the course of prostate cancer. It will not, to the best of their knowledge, suppress or cure it. But while eating a healthy diet that is rich in fruits and vegetables and getting exercise may not cure cancer, it can help the body become stronger and healthier, which can help patients tolerate cancer treatments.
What is prostate cancer?
Prostate cancer is cancer that happens in the prostate which is a small walnut-shaped gland in men that produces the seminal fluid that transports and nourishes sperm. It is one of the most common types of cancer in men and prostate cancer grows slowly and is confined to the prostate gland, where it may not cause harm.
But while some types of prostate cancer grow slowly and may need minimal treatment or no treatment at all, other types are aggressive and can spread fast.