People use fish oil for many health reasons, including the prevention of prostate cancer. Fish oil contains omega 3 fatty acids, which are believed to fight cancer.
One article (1) refuted this idea, however. The article cited a research study involving around 2000 men, some of whom had prostate cancer and others who did not have cancer. People who had the highest amount of omega 3 fatty acids in their body had a greater risk of prostate cancer when compared to those who did not have prostate cancer.
This might mean that fish oil is not at all preventative against prostate cancer but might instead increase the chances that a person could get prostate cancer from consuming fish oil and other sources of omega 3 fatty acids.
Source: 1.Wehrwein P. High intake of omega-3 fats linked to increased prostate cancer risk.
Dr. Adem Gunes