High plant-based diet may prevent prostate cancer progression

High intake of plant-based foods after prostate cancer diagnosis was associated with a lower risk of disease progression, according to a recent study.

“Plant-based diets (ie, diets incorporating a greater proportion of one’s daily caloric intake from plant sources) are increasingly popular and have nutritional benefits among people diagnosed with various chronic diseases, including prostate cancer,” said the researchers.

“Current dietary recommendations for cancer patients and the general population emphasize a plant-based diet high in fruits, vegetables, and whole grains ... Fruits and vegetables contain a variety of phytochemicals, including antioxidants and anti-inflammatory compounds, that have been shown to protect against prostate cancer,” they added.

“Yet, little is known about plant-based dietary patterns and prostate cancer-specific clinical outcomes after diagnosis,” the researchers noted.

Using data from the Cancer of the Prostate Strategic Urologic Research Endeavor registry, the researchers identified 2,062 men diagnosed with prostate cancer (median age at diagnosis 65 years) who completed a comprehensive diet and lifestyle questionnaire, including a validated Food Frequency Questionnaire (FFQ). Overall plant-based diet index (PDI) and healthful plant-based diet index (hPDI) scores were used to assess the association between plant-based diet intake and disease progression risk. [JAMA Network Open 2024;doi:10.1001/jamanetworkopen.2024.9053]

At a median follow-up of 6.5 years after FFQ completion, 190 progression events and 61 prostate cancer–specific mortality events were observed.

Based on PDI, patients who had the highest intake of plant-based foods demonstrated a 47-percent lower risk of cancer progression compared with those who had the lowest intake (hazard ratio [HR], 0.53; ptrend=0.003).

On the other hand, no association was found between hPDI and the risk of cancer progression (HR, 0.81, 95 percent CI, 0.54–1.20; ptrend=0.34).

Of the 680 patients with Gleason grade ≥7 at diagnosis, a 55-percent lower risk of progression was observed among those in the highest vs the lowest hPDI quintile (HR, 0.45, 95 percent CI, 0.25–0.81; ptrend=0.01), but no statistically significant association was observed in those with Gleason grade <7.

In addition, there was no statistically significant association between the dietary index and prostate-specific cancer mortality (highest vs lowest quintile: HR, 0.53, 95 percent CI, 0.17–1.55; ptrend=0.16).

The results are consistent with previous reports suggesting that plant-based diets may improve prostate cancer outcomes, and these contribute to the emerging body of research that indicates the positive association between plant-based diets and health outcomes, noted the researchers.

“Overall, the findings of this cohort study suggest that plant-based dietary patterns may be inversely associated with the risk of prostate cancer progression. However, future research and replication of our findings is needed,” said the researchers.