A new study in the Journal of the National Cancer Institute reported a link between omega-3 fatty acids and prostate cancer. The large-scale study compared 834 men who were diagnosed with prostate cancer to 1,393 men who did not have cancer. The researchers measured the blood levels of omega-3 fatty acids and found that men with the highest concentrations had a 71% greater risk of developing high-grade prostate cancer. The increased risk for developing any type of prostate cancer was 44%.
Three types of omega-3 fatty acids (EPA, DPA, and DHA) were measured in the study. These anti-inflammatory fatty acids are found in fatty fish and fish-oil supplements.
Prostate cancer is the second most common cancer in men in the United States, affecting about 1 in 6 men. The American Cancer Society estimates that over 238,000 new cases of prostate cancer will be diagnosed in 2013.
This is the second study on omega-3 fatty acids and prostate cancer risk by scientists at Fred Hutchinson Cancer Research Center. The first study, published in 2011, reported a similar link: men with the highest blood concentrations of DHA omega-3 fatty acid had double the risk of developing prostate cancer.
Another large study, carried out in Europe in 2008, found a link between EPA omega-3 fatty acid and increased prostate cancer risk.
Researchers are still trying to answer the question of why omega-3s might cause prostate cancer.