Protecting Against Prostate Cancer
The size and shape of a walnut, the prostate gland is wrapped around the male urethra--the tube that transports urine from the bladder to outside the body. Why it exists is not fully understood but what is known is that the prostate is prone to cancerous changes from around the age of 45.
In American men, these changes can be particularly dire. They are 10 times more likely to die from prostate cancer than Japanese men, and the death toll annually hits more than 31,000.
But both groups are equally likely to be diagnosed with an early form of the disease. In Japan, it seems, something stops prostate cancer before it becomes lethal. That braking system could involve the diet.
Research presented in Anaheim this summer at the annual meeting of the American Urological Assn. revealed a possible explanation for this apparent protective effect of the Japanese diet.
The Japanese eat many soy-based foods, which are rich in isoflavones-plant nutrients similar to the human hormone estrogen. Blood tests have revealed that Japanese men, on average, have isoflavone levels more than 100 times higher than typical American men.
UC Davis scientists showed that, in laboratory tests on prostate tumors, one particular type of soy isoflavone directly reduced the growth of prostate tumors. This isoflavone, genestein, appeared to slow prostate cell growth and lower levels of a protein that encourages the growth of cancer cells.
But foods other than soy products may also play a role in protecting men from prostate cancer. Studies worldwide have consistently linked a higher intake of tomatoes and tomato-based products with lower prostate cancer deaths.
Tomatoes are bursting with lycopene, the vibrant pigment that gives them their stunning red color, and research published in the journal Cancer Epidemiology, Biomarkers and Prevention in August sheds some light on lycopene’s possible protective role.
The work, carried out at the University of Honolulu, showed that 30 milligrams of lycopene daily reduced production of a known prostate cancer trigger.
This amount of lycopene is not hard to eat. It is found for example in a 5-ounce serving of tomato-based pasta sauce. A bowl of tomato soup provides 9 milligrams, a small glass of tomato juice 10 milligrams and a tablespoon of ketchup 3 milligrams. Other red fruits such as watermelon and pink grapefruit also contain useful amounts of lycopene.
More research is needed to confirm the potential protective and therapeutic effects of soy-and tomato-based foods. Until then, men should consider regular consumption of soy products such as milk, yogurt and other products, and they shouldn’t skimp on the ketchup, baked beans, pasta sauce and fresh and canned tomatoes. Such dietary habits could prove crucial in the fight against prostate cancer.
