A prospective study of polyunsaturated fatty acid levels in blood and prostate cancer risk

Cancer Epidemiol Biomarkers Prev. 2007 Jul;16(7):1364-70. doi: 10.1158/1055-9965.EPI-06-1033. Epub 2007 Jun 21.


Background: Animal models suggest that n-3 fatty acids inhibit prostate cancer proliferation, whereas n-6 fatty acids promote it, but epidemiologic studies do not uniformly support these findings.

Methods: A nested case-control study was conducted among 14,916 apparently healthy men who provided blood samples in 1982. Blood fatty acid levels were determined for 476 men diagnosed with prostate cancer during a 13-year follow-up and their matched controls. Conditional logistic regression was used to estimate the relative risks (RR) and 95% confidence intervals (95% CI) of total, non-aggressive (stage A/B and Gleason < 7) and aggressive (stage C/D, Gleason >or= 7, subsequent distant metastasis or death) prostate cancer associated with blood levels of specific fatty acids expressed as percentages of total fatty acids.

Results: Whole blood levels of all long-chain n-3 fatty acids examined and of linoleic acid were inversely related to overall prostate cancer risk (RR(Q5vs.Q1), 0.59; 95% CI, 0.38-0.93; P(trend) = 0.01 for total long-chain n-3 fatty acids and RR(Q5vs.Q1), 0.62; 95% CI, 0.41-0.95; P(trend) = 0.03 for linoleic). Blood levels of gamma-linolenic and dihomo-gamma-linolenic acids, fatty acids resulting from the metabolism of linoleic acid, were directly associated with prostate cancer (RR, 1.41; 95% CI, 0.94-2.12; P(trend) = 0.05 for gamma-linolenic and RR, 1.54; 95% CI, 1.03-2.30; P(trend) = 0.02 for dihomo-gamma-linolenic acid). Levels of arachidonic and alpha-linolenic acids were unrelated to prostate cancer.

Conclusions: Higher blood levels of long-chain n-3 fatty acids, mainly found in marine foods, and of linoleic acid, mainly found in non-hydrogenated vegetable oils, are associated with a reduced risk of prostate cancer. The direct associations of linoleic acid metabolites with prostate cancer risk deserve further investigation.

Publication types

  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural

MeSH terms

  • Adult
  • Aged
  • Case-Control Studies
  • Double-Blind Method
  • Fatty Acids, Unsaturated / blood*
  • Humans
  • Male
  • Medical Records
  • Middle Aged
  • Placebos
  • Prospective Studies
  • Prostate
  • Prostatic Neoplasms / blood*
  • Prostatic Neoplasms / epidemiology
  • Risk Factors
  • United States / epidemiology


  • Fatty Acids, Unsaturated
  • Placebos