In an animal study, consumption of walnuts has been demonstrated to help ward off breast cancer in mice.
Researchers led by Elaine Hardman, a cell biologist at Marshall University School of Medicine in Huntington, West Virginia, compared breast cancer incidence in mice eating a diet that included lots of walnuts (the equivalent for humans of two ounces, or about 14 whole walnuts per day), and those eating a similar diet with no walnuts. They discovered that the walnut munchers were less likely to develop breast tumors, and if they did, their tumors were smaller and affected fewer mammary glands. The mice, which are genetically engineered to develop cancer, normally get tumors within five months, Hardman says. But, she adds, “At 145 days, 100 percent of the mice on the normal diet had cancer, and 50 percent of the mice on the walnut diet had cancer.”
The authors of the study speculate that these protective effects are due walnuts’ omega-3 fatty acid, antioxidant, and phytosterol content.