If you’ve been following prostate cancer-related health and wellness news for the past few years, you may have heard about the connection between plant-based diets and prostate cancer. For example, Stacy Loeb, MD, MSc, PhD (hon), a urologist at NYU and the Manhattan VA, previously discussed the beneficial association with sexual and urinary function after prostate cancer treatment in this video.
Now, a team led by Vivian Liu and Dr. Stacey Kenfield of UCSF have published the results of a study showing more encouraging findings: among people already diagnosed with prostate cancer, eating a plant-based diet was associated with a lower risk of the cancer coming back or getting worse.
Who was in the study?
This was an “observational” study, meaning that the researchers analyzed patient information that had been collected over time. The team used data on more than 2,000 patients who were followed for nearly 20 years. All of these patients had been diagnosed with localized prostate cancer and had also completed a detailed diet and lifestyle questionnaire. The database also included clinical data, such as PSA levels, need for additional treatment, and death.
What is the plant-based diet in this study?
Categories of foods and beverages were considered as follows:
- Healthful plant foods: whole grains, fruits, vegetables, nuts, legumes, vegetable oils, tea and coffee
- Unhealthful plant foods: fruit juices, sugar-sweetened beverages, refined grains, potatoes, and sweets or desserts
- Animal foods: animal fats, dairy, eggs, fish and seafood, meat, and miscellaneous animal-based foods
Each patient was given dietary pattern scores based on the types and frequency of foods & beverages consumed, as reported on their questionnaire.
An overall plant-based diet index score was computed by adding points for healthful + unhealthful plant foods; fewer points were given for those eating the most animal foods. Additionally, a healthful plant-based diet index score was computed by assigning more points for greater amounts of healthful plant-based foods consumed, and fewer points for greater amounts of unhealthful plant-based foods and animal foods consumed.
What were the results?
The researchers focused on prostate cancer progression, which they defined as biochemical recurrence, additional treatment, bone metastases, or death from prostate cancer.
Patients with the highest overall plant-based diet scores (i.e., who ate more plant-based and less animal-based food) were 47% less likely to have prostate cancer progression, compared to patients with the lowest scores. (To put this in perspective, seat belt use reduces front seat passenger deaths by 45%.)
Considering all patients in the study, a healthful plant-based diet (i.e., consuming relatively more legumes, nuts, veggies, etc.) was not linked to risk of disease progression. However, among patients with more aggressive disease (Gleason grade 7 or higher), the healthful plant-based diet was associated with lower risk: patients with higher healthful plant-based diet scores were 55% less likely to have disease progression vs. those with the lowest scores.
What this means for patients
This study provides more evidence that for patients diagnosed with localized prostate cancer, choosing plant-based foods rather than animal products may be associated with a lower risk of your prostate cancer getting worse or coming back. You don’t need to go completely vegan to reap some benefit.
Patients with localized prostate cancer are actually more likely to die of heart attack or stroke, rather than of their prostate cancer. The benefits of a plant-based diet are well-documented. The Academy of Nutrition and Dietetics notes that “vegetarians and vegans are at reduced risk of certain health conditions, including ischemic heart disease, type 2 diabetes, hypertension, certain types of cancer, and obesity.”
Consider adopting a more plant-based diet as an “insurance policy” against many common diseases, and which also may be associated with benefits for the prostate. Speak with your doctor or a nutritionist for advice on getting enough protein and other nutrients if you’re not sure.
Looking for some recipes to help boost your healthful plant-based diet score?
Check out:
Sweet Potato, Tofu, and Spinach Curry
Green Burger
Southwestern Black Bean & Corn Salad