A review of numerous studies finds no strong evidence indicating a significantly reduced risk of cancer associated with the consumption of omega-3 fatty acids, according to an article in the January 25 issue of JAMA: The Journal of the American Medical Association.
Epidemiological studies have suggested that groups of people who consume diets high in omega-3 fatty acids, found in certain fish and vegetables, may experience a lower prevalence of some types of cancer, according to background information in the article. Many small trials have attempted to assess the effects of omega-3 fatty acids on cancer treatment by adding omega-3 fatty acid to the diet either as omega-3 fatty acid-rich foods or as dietary supplements. Because of the results of some studies, a number of omega-3 fatty acid-containing dietary supplements have appeared on the market claiming to protect against the development of a variety of conditions including cancer, even though studies have reported mixed results.
Catherine H. MacLean, M.D., Ph.D., of RAND Health, Santa Monica, Calif., and colleagues assessed the validity of claims that omega-3 fatty acids prevent cancer by systematically reviewing the literature for studies that evaluated the effect of omega-3 fatty acids on the incidence of cancer. Using several databases and other sources, the researchers identified 38 articles, published between 1966 to October 2005, which met the study criteria. Reviewers independently abstracted detailed data about the incidence of cancer, the type of cancer, the number and characteristics of the patients, details on the exposure to omega-3 fatty acids, and the elapsed time between the intervention and outcome measurements.