Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery.
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.
Demark-Wahnefried
Wendy
W
Division of Cancer Prevention and Population Sciences, The University of Texas M. D. Anderson Cancer Center, P.O. Box 301439, Unit 1330, Houston, TX 77230-1439, USA. wdemarkw@mdanderson.org
Polascik
Thomas J
TJ
George
Stephen L
SL
Switzer
Boyd R
BR
Madden
John F
JF
Ruffin
Mack T
MT
Snyder
Denise C
DC
Owzar
Kouros
K
Hars
Vera
V
Albala
David M
DM
Walther
Philip J
PJ
Robertson
Cary N
CN
Moul
Judd W
JW
Dunn
Barbara K
BK
Brenner
Dean
D
Minasian
Lori
L
Stella
Philip
P
Vollmer
Robin T
RT
D000328:Adult; D000368:Aged; D014408:Biomarkers, Tumor / Q000097:blood; D018752:Diet, Fat-Restricted; D019587:Dietary Supplements; D019597:Flax; D006801:Humans; D008297:Male; D008875:Middle Aged; D016012:Poisson Distribution; D011300:Preoperative Care; D011471:Prostatic Neoplasms / Q000178:diet therapy* / Q000473:pathology / Q000601:surgery; D018709:Statistics, Nonparametric
D014408:Biomarkers, Tumor