Pharmacodynamics of Fish Oil: Protective Effects Against Prostate Cancer in TRAMP Mice Fed with a High Fat Western Diet

Numerous epidemiological studies suggest that frequent consumption of fish would decrease certain major inflammatory-related chronic diseases including cancer. Aims: To investigate the cancer chemoprotective effect of fish oil (FO) in Transgenic Adenocarcinoma of Mouse Prostate (TRAMP) mice fed a FO diet (10% Menhaden fish oil; FO group) versus a 20% high fat diet (HF group; typical of a Western diet), both with a total content of 20% fat and equal calories.
Methods: For each diet, two experimental arms were performed. The mice were put on diet at 8th or 12th week of age for periods of 14 and 10 weeks, the experiments being terminated when the mice reached 22 weeks of age. The animals were monitored weekly for health, and upon necropsy were examined for whole body metastasis, and prostate tissues were confirmed with histopathology.
Results: At the end of the study, the FO group had significantly reduced prostate tumor weight (p<0.05) compared to the HF group. The incidence of palpable tumors and carcinomas was also lowered. Finally, there was no metastasis found in the FO group, whereas in the HF group, 16.7% of the mice were found to have metastases.
Conclusions: This is the first study showing the beneficial effects of FO against prostate cancer having a HF diet, suggesting potential beneficial effects of FO in humans consuming HF in their diet.