Whole Tomatoes, Not Just Lycopene, May Prevent Prostate Cancer

CHAMPAIGN, Ill.--Eating whole tomatoes and whole tomato products rather than lycopene supplements may help prevent prostate cancer, according to researchers at the University of Illinois. Their placebo-controlled trial was published in the Nov. 5 issue of the Journal of the National Cancer Institute (95, 21:1578-86, 2003) (www.jncicancerspectrum.oupjournals.org/jnci).

In the study, 194 male rats were treated with chemicals to induce prostate cancer and fed diets that contained whole tomato powder (13 mg/kg of lycopene), lycopene (beadlet form, 161 mg/kg of lycopene), or control beadlets with no added ingredients. Half of the rats in each group were given 20-percent fewer calories, and half had no caloric restrictions. Rats fed tomato powder were less likely to die of cancer than rats fed the lycopene or control diets, according to the study: 62 percent of the tomato powder group, 72 percent of the lycopene group and 80 percent of the control group died of prostate cancer. Diet restriction contributed to a 14-percent decrease in cancer development when compared to the non-restricted diet (65 percent vs. 79 percent, respectively).

One of the study researchers, John Erdman Jr., professor of food science, human nutrition and internal medicine at the University of Illinois said, "It has been unclear whether lycopene itself is protective. This study suggests that lycopene is one factor involved in reducing the risk of prostate cancer. ... This also suggests that taking lycopene as a dietary supplement is not as effective as eating whole tomatoes. We believe people should consume whole tomato products--in pastas, in salads, in tomato juice and even on pizza."

Zohar Nir, Ph.D., vice president of sales and marketing for Lycored Industries, supplier of Lyc-O-Mato natural tomato complex, said the findings were not surprising. "We have said all along that lycopene by itself, whether natural or synthetic, was not solely responsible for reducing prostate cancer risks," Nir said. "This study re-confirmed numerous other findings that have shown the beneficial properties of a natural tomato complex containing lycopene plus other necessary tomato phytonutrients: phytoene, phytofluene, natural vitamin E, beta-carotene and phytosterols."

Researchers further concluded "tomato products contain compounds in addition to lycopene that modify prostate carcinogenesis. ... Tomato phytochemicals and diet restriction may act by independent mechanisms."