WINSTON-SALEM, N.C.—A new study in mice suggests a diet high in omega-3 polyunsaturated fatty acids (PUFAs) could reduce the risk of developing prostate cancer (J Clin Invest, ePub June 21, 2007). Researchers from Wake Forest University Baptist Medical Center used control animals and mice engineered without the Pten-gene to suppress prostate tumor growth to determine the influence of fatty acids on cancer risk. Animals fed a diet rich in n-3s (ratio of 1-to-1 with n-6) had reduced prostate tumor growth and slower histopathological progression, as well as increased survival; diets high in n-6s (40-to-1 ratio n-6-to-n-3) had the opposite effect. Providing animals with an n-3 desaturase, which converts n-6 to n-3, reduced tumor growth similarly to the n-3 diet. Mice with the tumor suppressor gene remained free of tumors and had 100-percent survival rates, regardless of diet. In Pten-knockout mice, survival was 60 percent in animals on the high n-3 diet and 0 percent in those on the high n-6 diet.
In addition, tumors from mice on the n-3 diet had higher apoptotic indexes and lower proportions of phosphorylated Bad, a signaling gene. The researchers therefore suggested modulation of prostate cancer development by n-3 EFAs is mediated in part through Bad-dependent apoptosis.
“This suggests if you have good genes, it may not matter too much what you eat,” said Yong Q. Chen, Ph.D., a professor of cancer biology and senior researcher. “But if you have a gene that makes you susceptible to prostate cancer, your diet can tip the balance. Our data demonstrate the importance of gene-diet interactions, and that genetic cancer risk can be modified favorably by omega-3 PUFA.”
Chen cautioned the study used long-chain n-3s found in fish oil, and that further research would be necessary to determine whether n-3s from plants could provide the same results.
