Previous researches involving dietary methods have shown conflicting findings. Authors sought to assess the association of
prostate cancer risk with blood levels of omega-3
polyunsaturated fatty acids (n-3 PUFA) through a meta-analysis of human epidemiological studies in available online databases (July, 2012). After critical appraisal by two independent reviewers, Newcastle-Ottawa Quality Assessment Scale (NOQAS) was used to grade the studies. Six case control and six nested case control studies were included. Results showed nonsignificant association of overall effect estimates with total or advanced
prostate cancer or high-grade
tumor. High blood level of
alpha-linolenic acid (ALA) had nonsignificant positive association with total
prostate cancer risk. High blood level of
docosapentaenoic acid (DPA) had significant negative association with total
prostate cancer risk. Specific
n-3 PUFA in
fish oil,
eicosapentaenoic acid (EPA), and
docosahexaenoic acid (DHA) had positive association with high-grade prostate
tumor risk only after adjustment of interstudy variability. There is evidence that high blood level of DPA that is linked with reduced total
prostate cancer risk and elevated blood levels of
fish oils, EPA, and DHA is associated with high-grade prostate
tumor, but careful interpretation is needed due to intricate details involved in prostate
carcinogenesis and
N-3 PUFA metabolism.