Fish consumption appears to be helpful in reducing the risk of developing prostate cancer. Around the world, prostate cancer incidence can vary up to 60-fold from country to country, suggesting a relationship to lifestyle and diet. Researchers from McGill University Research Centre, conducted a meta-analysis (study of studies) to determine a relationship between prostate cancer and dietary fish intake (Szymanski, Wheeler, Mucci, 2010).
This study evaluated 12 case-control studies (5777 cases and 9805 controls) and 12 cohort studies (totaling 445,820 subjects). While prostate cancer incidence was lower in those who consumed the most fish, this was not statistically significant. Unfortunately, the studies were so varied in their methodology, a conclusion could not be made regarding how much fish one needs to consume in order to gain a protective benefit.
Szymanski, K.M., Wheeler, D.C. & Mucci, L.A. 2010. Fish consumption and prostate cancer risk: a review and meta-analysis. American Journal of Clinical Nutrition, 92, 1223-1233.