Prostate cancer risk and consumption of fish oils: a dietary biomarker-based case-control study

Experimental studies suggest that the risk of prostate cancer is reduced wi th the intake of long-chain n-3 polyunsaturated fatty acids derived from ma rine foods, such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (D HA), However, few human studies have been conducted due to difficulties in assessing the dietary intake of these fatty acids. The authors examined the relationship between prostate cancer risk and EPA and DHA in erythrocyte b iomarkers in a population-based case-control study in Auckland, New Zealand during 1996-1997 involving 317 prostate cancer cases and 480 age-matched c ommunity controls. Reduced prostate cancer risk was associated with high er ythrocyte phosphatidylcholine levels of EPA (multivariate relative risk = 0 .59; 95% confidence interval 0.37-0.95, upper vs lowest quartile) and DHA ( multivariate relative risk = 0.62; 95% confidence interval 0.39-0.98, upper vs lowest quartile). These analyses support evidence from in vitro experim ents for a reduced risk of prostate cancer associated with dietary fish oil s, possibly acting via inhibition of arachidonic acid-derived eicosanoid bi osynthesis. (C) 1999 Cancer Research Campaign.