A 30-year study carried out on over 6,000 Swedish men has revealed that eating fatty fish could significantly reduce the risk of developing prostate cancer. Researchers from the Karolinska Institute , in Stockholm, explained in The Lancet medical journal that participants in the study were asked to record their dietary and physical habits. Over the course of the next 30 years, 466 men were diagnosed with prostate cancer, and 340 have died from the disease.