Dietary long-chain n-3 fatty acids for the prevention of cancer: a review of potential mechanisms

Am J Clin Nutr. 2004 Jun;79(6):935-45. doi: 10.1093/ajcn/79.6.935.


Increasing evidence from animal and in vitro studies indicates that n-3 fatty acids, especially the long-chain polyunsaturated fatty acids eicosapentaenoic acid and docosahexaenoic acid, present in fatty fish and fish oils inhibit carcinogenesis. The epidemiologic data on the association between fish consumption, as a surrogate marker for n-3 fatty acid intake, and cancer risk are, however, somewhat less consistent. This review highlights current knowledge of the potential mechanisms of the anticarcinogenic actions of n-3 fatty acids. Moreover, a possible explanation of why some epidemiologic studies failed to find an association between n-3 fatty acid intake and cancer risk is provided. Several molecular mechanisms whereby n-3 fatty acids may modify the carcinogenic process have been proposed. These include suppression of arachidonic acid-derived eicosanoid biosynthesis; influences on transcription factor activity, gene expression, and signal transduction pathways; alteration of estrogen metabolism; increased or decreased production of free radicals and reactive oxygen species; and mechanisms involving insulin sensitivity and membrane fluidity. Further studies are needed to evaluate and verify these mechanisms in humans to gain more understanding of the effects of n-3 fatty acid intake on cancer risk.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Animals
  • Breast Neoplasms / prevention & control*
  • Diet*
  • Eicosanoids / biosynthesis
  • Epidemiologic Methods
  • Fatty Acids, Omega-3* / administration & dosage
  • Fatty Acids, Omega-3* / metabolism
  • Fatty Acids, Omega-3* / therapeutic use
  • Female
  • Fishes*
  • Gene Expression Regulation, Neoplastic / drug effects*
  • Humans
  • Male
  • Meat*
  • Prostatic Neoplasms / prevention & control*
  • Signal Transduction / drug effects


  • Eicosanoids
  • Fatty Acids, Omega-3