A diet rich in omega-3 polyunsaturated fatty acids found in certain fish or fish oil, nuts, seeds, and vegetable oils may help lower prostate cancer risk in individuals with a genetic predisposition to cancer.
So conclude researchers from Wake Forest University School of Medicine in their study appearing online on June 21 in advance of publication in the July print issue of the Journal of Clinical Investigation.
While many genetic mutations are known to predispose to cancer, it has remained unclear whether dietary fat can modulate the risk of developing cancer in genetically predisposed individuals. Some studies suggest that a diet rich in omega-3 polyunsaturated fatty acids reduces cancer incidence.
To determine the influence of fatty acids on prostate cancer risk in animals with a defined genetic predisposition to cancer, Yong Chen and colleagues studied Pten-knockout mice (which are predisposed to develop prostate tumors) and the effects on these mice of diets with defined levels of specific polyunsaturated fatty acids. The authors found that a nutritionally balanced diet high in omega-3 fatty acid reduced prostate tumor growth and increased survival in these animals, whereas omega-6 fatty acids had the opposite effects.
Furthermore, introduction into the Pten-knockout mice of the enzyme omega-3 desaturase, which converts omega-6 to omega-3, reduced tumor growth in a manner similar to the omega-3–rich diet. The researchers went on to show that the effect of polyunsaturated fatty acids on prostate cancer development is mediated in part through cell death that is dependent on a protein known as Bad.
Together, the data highlight the importance of the interaction between genes and diet in prostate cancer and imply a beneficial effect of omega-3 polyunsaturated fatty acids on delaying the onset of human prostate cancer. It will be interesting in future studies to determine if any beneficial effects can also be achieved by supplementing the diet with omega-3 polyunsaturated fatty acids after tumor initiation has occurred.