Walnuts Cut Prostate Cancer Risk

Walnuts, of all things, appear to slow the growth of prostate cancer tumors–in mice at least. Researchers at the University of California at Davis have found that mice genetically programmed to develop prostate cancer had smaller, slower growing tumors if they consumed a diet containing walnuts. A U.C. Davis news release reports that when researchers at the school, working with colleagues at the USDA Western Regional Research Center in Albany, Calif., studied tumor size in mice fed different diets for 9, 18 and 24 weeks, they found that the mice that ate the human equivalent of 2.8 ounces of whole walnuts daily, gained weight at the same rate as mice fed a soybean oil diet formulated to match the nutrients, fat levels and fatty acid profiles of the walnut diet.  At 18 weeks, however, the tumor weight of the walnut-fed group was approximately half that of the mice consuming the soybean oil diet, and overall, the rate of tumor growth was 28 percent lower in the walnut-fed mice. The researchers point out that a low-fat diet is recommended for reducing a man’s risk for developing or slowing growth of existing prostate cancer, but the UC Davis study suggests that excluding walnuts, which are high in fat but rich in omega-3 polyunsaturated fats, antioxidants and other plant chemicals, may sacrifice a protective effect of walnuts on tumor growth. Paul Davis, a research nutritionist at the U.C. Davis Cancer Center, says other studies have hinted that walnuts may prevent the actual formation of tumors. “But more immediately,” he says, “our findings suggest that eating a diet containing walnuts may slow prostate tumor growth so that the tumor remains inside the prostate capsule. If proven applicable in humans, men with prostate cancer could die of other causes – hopefully old age.” Read more from U.C. Davis.