Plant-Based Diet May Reduce Risk of Prostate Cancer Progression

Diane Riccardi, Registered Dietician

According to a recent study published in JAMA Network Open, a plant-based diet may hold exciting promise in extending survival for prostate cancer patients.

Researchers looked at more than 2,000 men diagnosed with nonmetastatic prostate cancer. They found that those with the highest intake of plant foods in the overall plant-based diet index had lower risk of prostate cancer progression compared with those with the lowest intake.

These findings suggest that eating a primarily plant-based diet may be associated with better prostate cancer–specific health outcomes among men living with the disease.

The American Cancer Society (ACS) recommends eating a more plant-based diet, exercising regularly, maintaining a healthy weight and avoiding alcohol. However, few cancer survivors fully adhere to these guidelines after their cancer diagnosis and treatment, suggesting the need for patient education to close the gap between ideal and actual practices. Patients are often unaware of the benefits of a healthy lifestyle in terms of cancer progression; thus, patient education and counseling are central to the mission of the Survivorship Clinic at Moffitt Cancer Center.  

What is a plant-based diet?

A plant-based diet is built around a plate filled with mostly vegetables, fruits, whole grains and beans.  Many types have been found to offer health advantages.  

• Flexitarian: mostly plant foods; can include dairy, eggs, fish, chicken, and occasionally red meat
• Pescatarian: mostly plant foods and includes fish (and possibly dairy and eggs)
• Vegetarian: mostly plant foods and includes dairy and/or eggs
• Vegan: only plant foods; no dairy, eggs, fish, seafood, poultry, meat or other animal-derived foods

How might choosing a diet that prioritizes plant foods help improve outcomes among patients with prostate cancer? 

First, plants contain several cancer-fighting compounds, evidenced in their rainbow of colors. These compounds work together to reduce inflammation and cell damage, which can promote cancer growth.

Additionally, plant-based diets low in calories and fiber help support a healthy weight, the most crucial lifestyle intervention to lower cancer risk.  

Meat reduction, mainly red and processed meats, limits the number of cancer-causing compounds we consume from cooking, curing and processing these meats.

Encouraging Evidence  

Previous studies have shown plant-eaters to develop prostate cancer at lower rates than meat-eaters. However, less is known about the impact of nutrition on the chance of cancer progressing or recurring after it has been treated, a pivotal concern for patients, their families and doctors.

Although no single food can prevent cancer, a dietary pattern representing the combination of foods that people consume, such as plants, is a better way to capture the health benefits. 

The results are not surprising for health professionals. After all, healthy lifestyle factors such as diet and physical activity have been shown to extend survival in the general population and long been recommended to lower the risk of cancer and other chronic diseases.   

But not all plant-based foods are equal — think chips and soda compared to a green salad. The study authors used a plant-based diet score to distinguish between the quality of the plant foods. Their results showed equal benefits of low and high-quality plant-based diets. However, among men with a greater risk of cancer returning, a Gleason grade 7 or higher at diagnosis, the higher quality plant-based diet was superior.

Plant-based diets are gaining traction as they show many health and environmental benefits. It is becoming more apparent that what may be best for the planet is best for all of us.

This study improves our understanding of the impact of plant-based diets on survivors’ health outcomes, guiding healthcare professionals who care for patients throughout the cancer continuum.

Written by Diane Riccardi, Registered Dietitian with the Survivorship Program