Daniel Koralek

University of North Carolina at Chapel Hill - Department of Epidemiology, CB #7435

PLCO (Learn more about this study)

2007-0017

Jun 12, 2007

Polyunsatruated Fat Intake and Prostate Cancer

Studies of dietary consumption of fats and prostate cancer have been inconclusive. Recent interest has focused on the influence that consumption of specific fatty acids may have on prostate cancer risk. Increases in polyunsaturated fat intakes in the western diet have correlated with increases in prostate cancer incidence. The long chain omega-3 (n-3) fatty acids docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA) have been shown to inhibit prostate carcinogenesis in cell culture studies and inversely associated with prostate cancer risk in some observational studies. However, alpha-linolenic acid (ALA), the most common n-3 fatty acid in the western diet, has not shown similar anticarinogenic effects in cell culture and animal studies, and has been found to be positively associated with prostate cancer in some, but not all, observational studies. Furthermore, omega-6 (n-6) fatty acids have been shown to promote tumor growth in cell culture studies. Linoleic acid (LA), the most common n-6 fatty acid in the diet, is metabolized to arachidonic acid (AA) by the same enzymes that synthesize EPA and DHA from ALA. Eicosanoids formed as metabolites of AA, including prostaglandins and thromboxanes, have been implicated in prostate growth and inflammation. Because of this enzymatic competition, it is thought that the ratio of n-6 to n-3 fatty acid consumption may be more important than the consumption of specific polyunsaturated fatty acids. EPA and DHA may inhibit prostate carcinogenesis by competing for a second set of enzymes, which are used in eicosanoid formation from AA (such as COX2). We propose to extend our earlier analysis of ALA intake in PLCO to investigate relations between prostate cancer and intakes of LA, ALA, DHA, EPA, and their ratios. We hope to leverage this well-designed prospective study to aid in our understanding of how dietary consumption of these fatty acids may impact prostate carcinogenesis.