Keith I. Block, M.D. follow us read our blog

Ask Dr. Block

Watermelon and Prostate Cancer

Question: Can you comment on watermelon, whether it is good or bad to help with prostate cancer?

Answer: This is a timely question! Watermelon is a wonderful summer fruit, and a truly healthy treat. The part of watermelon that’s most likely to help with prostate cancer is a phytochemical called lycopene. Fresh watermelon is even higher in lycopene than fresh tomato: 4532 micrograms per 100 grams of watermelon versus versus 2570 micrograms per 100 grams of fresh tomatoes (of course, tomato sauce and especially dried tomatoes are very concentrated lycopene sources and contain even more than watermelon). Pink grapefruit and red bell peppers are also good lycopene sources. These are all red or pink vegetables or fruits but, curiously, strawberries do not contain lycopene; their red color comes from other healthful phytochemicals.

How do we know lycopene is good for prostate cancer? The first indications that lycopene might be good for prostate cancer came from questionnaires in which patients were asked what foods they ate, and then followed for several years to see which of them developed prostate cancer. Patients who ate a lot of dishes made from tomato products were less likely to get prostate cancer than those who ate few tomato products. Next, there are at least 6 studies in which scientists contacted men who had had prostate biopsies indicating cancer and were scheduled to have their prostates removed. They gave the men lycopene rich supplements, usually tomato concentrates. When they examined the prostates that were removed after surgery, they found a variety of indications that the lycopene supplements had reduced the aggressiveness of the tumors relative to what was initially seen, or relative to what was experienced by men in control groups who didn’t get tomato products or lycopene.

So eating watermelon is certainly good for your prostate. You can’t eat watermelon all year, though, so do incorporate tomato products in your diet as well. Other good foods or supplements for prostate cancer are green tea, soy, and pomegranate juice. Also, prostate cancer is fueled by inflammation, so maintaining an anti-inflammatory diet and supplement regimen (see Chapter 15 in Life Over Cancer) is likely to be helpful for you.

Block KI. Nutritional interventions in cancer. Chapter 5. In Abrams D, Weil A. (eds). Integrative Oncology. 2009. Oxford University Press, New York, NY. pp75-104.