Well, good to know it is settled and looks like there are 2 choices: good, or not good. Which one to believe? As a food, I will say it keeps me regular, plus my blood pressure appears to be lower when including it in my diet. But you never know, since there is always another study it seems. A few of the studies in it's favor FWIW:nutritionfacts.org/questions/flax-seeds-and-prostate-cancer-risk/
Might flax seeds (ALA) increase prostate cancer risk?
Written by: Michael Greger M.D. on November 8th, 2012
There are a lot discussions and articles online about the supposed connection between flax seeds (ALA) and prostate cancer – suggesting that more flax consumed = increase chance of prostate cancer. I haven’t found this issue addressed on your website (sorry if I missed it). Can you comment? Thanks!
DSikes / Originally posted below Just the Flax, Ma’am
The latest meta-analysis of prospective studies found that, if anything, alpha-linolenic acid (ALA, the omega-3 fat in flax) was protective against prostate cancer. Men consuming more than 1.5 g/day appeared to have significantly lower risk (the amount found in about a tablespoon of ground flax seeds).
One of the reasons there’s been so much conflicting data is that ALA is found in great foods (dark green leafies) and less than great foods (meat), and so ALA intake is not necessarily a marker of healthy eating. What you want is a randomized controlled study of men with prostate cancer. Give half of them flax and see what happens. And that was done! (full text here)
Researchers at the University of Texas Anderson Cancer Center took a bunch of men with prostate cancer about a month before they were to go into surgery. Half were put on a few tablespoons of ground flax a day and after surgery their cancerous prostates were examined. The proliferation rates of the cancer in the flax-eaters were only half that of the controls, confirming the test-tube studies done on prostate cancer cells suggesting that flax can indeed slow prostate tumor growth.
This improvement was after only 30 days of flax. ( Also see: cebp.aacrjournals.org/content/17/12/3577.full.pdf+html
Test tube only: www.ncbi.nlm.nih.gov/pubmed/11911282
Anticancer Res. 2001 Nov-Dec;21(6A):3995-9.
Effect of mammalian lignans on the growth of prostate cancer cell lines.
Lin X1, Switzer BR, Demark-Wahnefried W.
Mammalian lignans, enterolactone (EL) and enterodiol (ED), have been shown to inhibit breast and colon carcinoma. To date, there have been no reports of the effect of lignans on prostatic carcinoma. We investigated the effects of ED and EL on three human prostate cancer cell lines (PC-3, DU-145 and LNCaP).
MATERIALS AND METHODS:
Cells were treated with either 0.1% (v/v) DMSO (vehicle) or 10-100 microM of EL, ED or genistein (positive control) for 72 hours. Cell viability was measured by the propidium iodide nuclei staining fluorometric assay with each assay performed in triplicate.
At 10-100 microM, EL significantly inhibited the growth of all cell lines, whereas ED only inhibited PC-3 and LNCaP cells. While EL was a more potent growth inhibitor than ED, both were less potent than genistein. The dose for 50% growth inhibition of LNCaP cells (IC50) by EL was 57 microM, whereas IC50 was 100 microM for ED, (the observed IC50 for genistein was 25 microM).
ED and EL suppress the growth of prostate cancer cells, and may do so via hormonally-dependent and independent mechanisms.
Urology. 2004 May;63(5):900-4.
Pilot study to explore effects of low-fat, flaxseed-supplemented diet on proliferation of benign prostatic epithelium and prostate-specific antigen.
Demark-Wahnefried W1, Robertson CN, Walther PJ, Polascik TJ, Paulson DF, Vollmer RT.
1Division of Urologic Surgery, Duke University Medical Center, Durham, North Carolina 27710, USA.
Dietary factors may influence the prostate and have an impact on prostatic growth and disease. A small number of studies have suggested that flaxseed-supplemented, fat-restricted diets may thwart prostate cancer growth in both animals and humans. Unknown, however, is the potential effect of such a diet on benign prostatic epithelium.
We undertook a pilot study to explore whether a flaxseed-supplemented, fat-restricted diet affects the proliferation rates in benign epithelium. We also explored the effects on circulating levels of prostate-specific antigen (PSA), total testosterone, and cholesterol. Fifteen men who were scheduled to undergo repeat prostate biopsy were instructed to follow a low-fat (less than 20% kcal), flaxseed-supplemented (30 g/day) diet and were provided with a supply of flaxseed to last throughout the 6-month intervention period. The PSA, total testosterone, and cholesterol levels were determined at baseline and at 6 months of follow-up. Reports from the original and repeat biopsies were compared, and proliferation (MIB-1) rates were quantified in the benign prostatic epithelium.
Statistically significant decreases in PSA (8.47 +/- 3.82 to 5.72 +/- 3.16 ng/mL; P = 0.0002) and cholesterol (241.1 +/- 30.8 to 213.3 +/- 51.2 mg/dL; P = 0.012) were observed. No statistically significant change was seen in total testosterone (434.5 +/- 143.6 to 428.3 +/- 92.5 ng/dL). Although 6-month repeat biopsies were not performed in 2 cases because of PSA normalization, of the 13 men who underwent repeat biopsy, the proliferation rates in the benign epithelium decreased significantly from 0.022 +/- 0.027 at baseline to 0.007 +/- 0.014 at 6 months of follow-up (P = 0.0168).
These pilot data suggest that a flaxseed-supplemented, fat-restricted diet may affect the biology of the prostate and associated biomarkers. A randomized controlled trial is needed to determine whether flaxseed supplementation, a low-fat diet, or a combination of the two regimens may be of use in controlling overall prostatic growth.
However, going by your heads up, I will certainly keep even a closer eye on my PSA!