Tomatoes and soy products both contain natural cancer-fighting compounds that research has shown independently boost health. But a new study has found the two provide a potent one-two punch when eaten together that is more effective in preventing prostate cancer than when either is eaten alone.
The findings, based on research involving mice at the University of Illinois, found bioactive substances in soy and tomatoes appear to work collectively to shrink and even destroy particularly aggressive tumors.
“In our study, we used mice that were genetically engineered to develop an aggressive form of prostate cancer. Even so, half the animals that had consumed tomato and soy had no cancerous lesions in the prostate at study's end,” said John Erdman, a professor of food science and nutrition who helped conduct the study, published online in Cancer Prevention Research. “All the mice in the control group — no soy, no tomato — developed the disease.”
Although the research involved mice, the researchers believe the findings have significant implications for men, as well.
Prostate cancer is the most frequently diagnosed cancer in men, but has nearly a 100 percent survival rate if it's caught early. But in countries where soy is eaten regularly, prostate cancer occurs at significantly lower levels, Erdman noted, probably as a result of health-boosting compounds called isoflavones — such as genistein, daidzein, and glycitein. Research has also shown lycopene, a key compound found in tomatoes, has potent anti-cancer properties.
For the new study, researchers fed mice one of four diets — containing 10 percent whole tomato powder; 2 percent soy germ; tomato powder plus soy germ; and neither tomato nor soy.
After 18 weeks, the results showed the soy- and tomato-fed mice had lower cancer rates than the others and those with diets containing both fared the best.
“Eating tomato, soy, and the combination all significantly reduced prostate cancer incidence,” Erdman said. “But the combination gave us the best results. Only 45 percent of mice fed both foods developed the disease compared to 61 percent in the tomato group, and 66 percent in the soy group.”
The findings suggest three to four servings of tomato products per week and one to two servings of soy foods daily could protect against prostate cancer.
The researchers added that the findings reinforce the recommendation that a diet featuring a wide variety of whole fruits and vegetables is the healthiest choice.
“It's better to eat a whole tomato than to take a lycopene supplement,” Erdman said. “It's better to drink soy milk than to take soy isoflavones. When you eat whole foods, you expose yourself to the entire array of cancer-fighting, bioactive components in these foods.”
Tags:
Health
