Sept. 30, 2004 -- Diets packed with colorful fruits and vegetable may help fight prostate cancer. According to German and Dutch researchers, low doses of the antioxidants lycopene and vitamin E may slow the growth of tumors in the prostate.
Several studies have suggested that lycopene-rich diets are associated with lower risk of prostate cancer, especially more aggressive cancers.
Lycopene is a nutrient that gives some fruits and vegetables their color. Lycopene and vitamin E are also potent antioxidants that have been studied for the prevention of many diseases.
The study was conducted by researchers including Jacqueline Limpens of the urology department at the Erasmus Medical Center in Rotterdam, Netherlands.
Limpens and colleagues tested the effects of daily lycopene and vitamin E alone or in combination on prostate tumor growth in mice. They tested both high and low doses of the supplements and compared the effects with placebo.
Only synthetic forms of lycopene and vitamin E were used.
They show that a combination treatment with low-dose lycopene and vitamin E had the strongest effect at slowing tumor growth -- a 73% slowing of growth on the 42nd day of the test.
The next best results came from the low dose of lycopene alone, which slowed tumor growth by 53% in the same time frame. No other single supplement treatment worked to stop prostate tumor growth.
It's too soon to know if prostate tumors in humans would behave the same way. Tests on men with prostate cancer are under way in Germany.
The researchers also can't say whether combining lycopene and vitamin E could prevent prostate tumors from forming.
Though no single nutrient is likely to be the magic bullet that stops prostate cancer, eating a healthy diet can't hurt.
"We would certainly recommend that all men regularly eat lycopene and vitamin E-rich foods" as part of a balanced diet, says Limpens in a news release.
She singles out processed tomato products, papayas, pink grapefruit, watermelon, wheat germs, whole grains, mangoes, leafy green vegetables, nuts, and olive oil as natural sources of the nutrients.
Supplements and fortified foods can help get enough lycopene and vitamin E, says Limpens.
The study was presented in Geneva, Switzerland at the European Organization for Research and Treatment of Cancer-National Cancer Institute-American Association for Cancer Research Symposium on Molecular Targets and Cancer Therapeutics.