Eating walnuts slows the growth of prostate cancer in mice and has other beneficial effects on the multiple genes related to the control of tumor growth and metabolism. Researchers at UC Davis and the US Department of Agriculture Western Regional Research Center in Albany, California made the discovery. "This study shows that when mice with prostate tumors consume an amount of walnuts that could easily be eaten by a man, tumor growth is controlled," Paul Davis, a nutritionist in the Department of Nutrition and a UC Davis Cancer Center researcher, told Science Daily. "This leaves me very hopeful that it could be beneficial in patients." Prostate cancer affects one in six American men and can be triggered by a number of environmental factors including diet. Walnuts are known to be beneficial for other health areas such as heart disease, but no study has been published specifically looking at its affect on prostate cancer. Davis fed whole walnuts to mice genetically programmed to contract the cancer. After 18 weeks, he and his team found that the tumors were significantly smaller in the walnut-eating mice than in those which hadn’t been fed the nuts.