Departments of Urology, University of California-Los Angeles, Los Angeles, California.
Molecular and Medical Pharmacology, and Pathology; Center for Human Nutrition; General Clinical Research Center; Division of Pediatric Endocrinology, School of Medicine; Department of Physiological Sciences, Statistics Core, Department of Medicine, University of California-Los Angeles, Los Angeles, California; and Department of Surgery, Durham Veterans Affairs Medical Center and Division of Urologic Surgery and Duke Prostate Center, Departments of Surgery and Pathology, Duke University Medical Center, Durham, North Carolina; Department of Pathology, VA Medical Center Greater Los Angeles Healthcare System, Los Angeles, California.
Preclinical studies suggest lowering dietary fat and decreasing the ratio of omega-6 to omega-3 polyunsaturated fatty acids decreases the risk of prostate cancer development and progression. We conducted a phase II randomized trial to test the effect of decreasing dietary fat combined with decreasing the dietary omega-6:omega-3 ratio on biomarkers related to prostate cancer development and progression. Patients undergoing radical prostatectomy were randomly assigned to receive a low-fat diet with 5 grams of fish oil daily (dietary omega-6:omega-3 ratio of 2:1) or a control Western diet (omega-6:omega-3 ratio of 15:1) for four to six weeks prior to surgery. The primary endpoint was change in serum insulin-like growth factor I (IGF-1) between arms. Secondary endpoints were serum IGFBP-1, prostate prostaglandin E2 levels, omega-6:omega-3 fatty acid ratios, COX-2, and markers of proliferation and apoptosis. Fifty-five patients were randomized and 48 completed the trial. There was no treatment difference in the primary outcome. Positive secondary outcomes in the low-fat fish oil versus Western group were reduced benign and malignant prostate tissue omega-6:omega-3 ratios, reduced proliferation (Ki-67 index), and reduced proliferation in an ex vivo bioassay when patient sera was applied to prostate cancer cells in vitro. In summary, four to six weeks of a low-fat diet and fish oil capsules to achieve an omega-6:omega-3 fatty acid ratio of 2:1 had no effect on serum IGF-1 levels, though in secondary analyses, the intervention resulted in decreased prostate cancer proliferation and decreased prostate tissue omega-6:omega-3 ratios. These results support further studies evaluating reduction of dietary fat with fish oil supplementation on modulating prostate cancer biology.
Written by:
Aronson WJ, Kobayashi N, Barnard RJ, Henning S, Huang M, Jardack PM, Liu B, Gray A, Wan J, Konijeti R, Freedland SJ, Castor B, Heber D, Elashoff D, Said J, Cohen P, Galet C. Are you the author?
Reference: Cancer Prev Res (Phila). 2011 Oct 25. Epub ahead of print.
doi: 10.1158/1940-6207.CAPR-11-0298
PubMed Abstract
PMID: 22027686
UroToday.com Prostate Cancer Section
