Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery
Wendy Demark-Wahnefried, Thomas J Polascik, Stephen L George, Boyd R Switzer, John F Madden, Mack T Ruffin 4th, Denise C Snyder, Kouros Owzar, Vera Hars, David M Albala, Philip J Walther, Cary N Robertson, Judd W Moul, Barbara K Dunn, Dean Brenner, Lori Minasian, Philip Stella, Robin T Vollmer, Wendy Demark-Wahnefried, Thomas J Polascik, Stephen L George, Boyd R Switzer, John F Madden, Mack T Ruffin 4th, Denise C Snyder, Kouros Owzar, Vera Hars, David M Albala, Philip J Walther, Cary N Robertson, Judd W Moul, Barbara K Dunn, Dean Brenner, Lori Minasian, Philip Stella, Robin T Vollmer
Abstract
Background: Prostate cancer affects one of six men during their lifetime. Dietary factors are postulated to influence the development and progression of prostate cancer. Low-fat diets and flaxseed supplementation may offer potentially protective strategies.
Methods: We undertook a multisite, randomized controlled trial to test the effects of low-fat and/or flaxseed-supplemented diets on the biology of the prostate and other biomarkers. Prostate cancer patients (n = 161) scheduled at least 21 days before prostatectomy were randomly assigned to one of the following arms: (a) control (usual diet), (b) flaxseed-supplemented diet (30 g/d), (c) low-fat diet (<20% total energy), or (d) flaxseed-supplemented, low-fat diet. Blood was drawn at baseline and before surgery and analyzed for prostate-specific antigen, sex hormone-binding globulin, testosterone, insulin-like growth factor-I and binding protein-3, C-reactive protein, and total and low-density lipoprotein cholesterol. Tumors were assessed for proliferation (Ki-67, the primary endpoint) and apoptosis.
Results: Men were on protocol an average of 30 days. Proliferation rates were significantly lower (P < 0.002) among men assigned to the flaxseed arms. Median Ki-67-positive cells/total nuclei ratios (x100) were 1.66 (flaxseed-supplemented diet) and 1.50 (flaxseed-supplemented, low-fat diet) versus 3.23 (control) and 2.56 (low-fat diet). No differences were observed between arms with regard to side effects, apoptosis, and most serologic endpoints; however, men on low-fat diets experienced significant decreases in serum cholesterol (P = 0.048).
Conclusions: Findings suggest that flaxseed is safe and associated with biological alterations that may be protective for prostate cancer. Data also further support low-fat diets to manage serum cholesterol.
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Source: PubMed