Does Eating Soy Prevent Prostate Cancer Recurrence?

Can eating or drinking soy prevent prostate cancer recurrence? One study says no.

Many men eat or drink soy products every day to prevent prostate cancer recurrence after surgical removal of the prostate, but a study found that there is no benefit to this practice. The report was published in the Journal of the American Medical Association. Researchers had men drink either a powdered soy protein drink or a placebo drink every day for two years. After two years, they saw no difference in the two groups in terms of prostate cancer recurrence.

People who question this study of just 150 men point out that the study is small. Researchers say that does not matter because they found almost no statistical difference between the two groups. Drinking soy beverages will not cause harm, but it doesn’t offer help in preventing the cancer from coming back either. The study does not say if there is benefit to drinking soy to prevent prostate cancer in the first place.

In places where people start eating soy early in life, such as Asian countries, the prostate cancer rate is much lower than in the US. Perhaps there is a lifelong benefit to eating soy, which is rich in isoflavones and anti-cancer properties.

Soy does not seem to play a role in prostate cancer recurrence after surgery. Also to consider is the fact that people in Asian countries drink large quantities (over five cups a day) of green tea, which has been found to slow the growth of prostate cancer cells and even cause the cells to die while stimulating certain immune system cells that fight cancer tumors. Other foods in your diet and lifestyle also play a role in preventing prostate cancer recurrence.

Other foods that do fight prostate cancer

Other foods and supplements besides green tea that studies have found to be helpful in fighting prostate cancer include:

  • Pomegranate juice
  • Broccoli
  • Cayenne pepper
  • Asian mushrooms such as shiitake
  • Omega-3 fatty acids found in salmon
  • Lycopene found in tomatoes
  • Curcumin found in turmeric

Many of these foods have been found to slow tumor development and even kill prostate cancer cells. When looking for natural ways to fight prostate cancer through diet, a well-rounded menu that incorporates these plus many other fruits and vegetables will boost your immunity and help you to prevent recurrence of prostate cancer.

Read more in our Prostate Cancer Health Center.


Bosland MC et al. Effect of soy protein isolate supplementation on biochemical recurrence of prostate cancer after radical prostatectomy: a randomized trial. JAMA 2013 Jul 10; 310(2): 170-78