A meta-study that reviewed dozens of previous studies has found no strong evidence indicating a significantly reduced risk of cancer associated with the consumption of omega-3 fatty acids. The new study, in the Journal of the American Medical Association, says that "there is little to suggest that omega-3 fatty acids reduce the risk of any single type of cancer." Some studies in the past have suggested that 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. These results have prompted a number of manufacturers to produce omega-3 fatty acid dietary supplements that claim to protect against the development of a variety of conditions including cancer.
To better understand what role omega-3 fatty acids might play, study leader Catherine H. MacLean, of RAND Health, reviewed previous 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 and 2005. MacLean said that after analysis, only 10 of these articles were relevant.
MacLean found that significant associations between omega-3 fatty acid consumption and cancer risk were reported for breast cancer in 4 studies. But further analysis showed that there were significant associations for both increased risk and decreased risk and far more estimates that did not demonstrate any association. The upshot was that no trend was found to support the theory that omega-3 fatty acids reduce overall cancer risk.
MacLean said the previous studies "did not provide evidence to suggest a significant association between omega-3 fatty acids and cancer incidence [and] dietary supplementation with omega-3 fatty acids is unlikely to reduce the risk of cancer."
Source: Journal of the American Medical Association
