Wendy Demark-Wahnefried of the University of Texas M. D. Anderson Cancer Center in Houston, along with scientists from Duke University and other research centers, report in the December, 2008 issue of Cancer Epidemiology, Biomarkers & Prevention their finding of a reduction in prostate cancer proliferation rates associated with flaxseed intake.
The current research involved 161 men with prostate cancer scheduled for surgical removal of the prostate gland. The men were randomized to receive a diet supplemented with 30 grams flaxseed per day, a low fat diet, a low fat diet supplemented with flaxseed, or their usual diet for an average of thirty days until the date of their surgery. Blood samples were analyzed for lipids, omega-3 fatty acids, and other factors at the beginning of the trial and prior to surgery. Prostate tumors were examined for proliferation and apoptosis following removal of the gland.
The groups that received flaxseed were found to have less than half the rate of tumor cell proliferation than men who consumed their usual diets. Although no significant effect on proliferation was observed among those who received a low fat diet without flax, both groups on low fat diets experienced a significant reduction in total and low-density lipoprotein cholesterol.
In their introduction to the article, the researchers note that flaxseed contains over 800 times the amount of lignans than most other foods. Lignans have been shown to have “antimitotic, antiangiogenic, antioxidant, and phytoestrogenic effects,” as well as an ability to reduce the 5-alpha-reductase enzyme which may be involved in the development of prostate cancer. Flax also provides omega-3 fatty acids which increase natural killer cell activity, alter tyrosine kinase cell signaling pathways, reduce cell membrane synthesis, influence cell receptor status and suppress the production of pro-inflammatory prostaglandin E2. Although flaxseed is high in the omega-3 fatty acid alpha-linolenic acid, the researchers found instead a significantly higher level of the omega-3 fatty acid eicosapentaenoic acid (EPA) in the red blood cells and prostate tissue of participants who received flaxseed, which suggests that ALA in flax was converted to EPA in the body.
“Although other studies have employed presurgical models to test the effects of complementary therapies on prostate cancer, to our knowledge, this has been the largest effort to date,” the authors announce. “The evidence suggests that flaxseed (a) is a good, low-cost source of select vitamins and minerals and fiber, (b) is well-accepted and safe to use, and © warrants further testing as a preventive or complementary therapy for prostate cancer.