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Flaxseed vs. Prostate Cancer

What happens when men with prostate cancer and prostatic intraepithelial neoplasia (PIN) are placed on a relatively low-fat diet supplemented with ground flaxseeds?

March 25, 2013 |
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Supplementary Info

Sources Cited

W. Demark-Wahnefried, C. N. Robertson, P. J. Walther, T. J. Polascik, D. F. Paulson, R. T. Vollmer. Pilot study to explore effects of low-fat, flaxseed-supplemented diet on proliferation of benign prostatic epithelium and prostate-specific antigen. Urology 2004 63(5):900 - 904

W. Demark-Wahnefried, T. J. Polascik, S. L. George, B. R. Switzer, J. F. Madden, M. T. R. th, D. C. Snyder, K. Owzar, V. Hars, D. M. Albala, P. J. Walther, C. N. Robertson, J. W. Moul, B. K. Dunn, D. Brenner, L. Minasian, P. Stella, R. T. Vollmer. Flaxseed supplementation (not dietary fat restriction) reduces prostate cancer proliferation rates in men presurgery. Cancer Epidemiol. Biomarkers Prev. 2008 17(12):3577 - 3587

J. V. Heymach, T. J. Shackleford, H. T. Tran, S.-Y. Yoo, K.-A. Do, M. Wergin, P. Saintigny, R. T. Vollmer, T. J. Polascik, D. C. Snyder, M. T. R. th, S. Yan, M. Dewhirst, A. B. Kunnumakkara, B. B. Aggarwal, W. Demark-Wahnefried. Effect of low-fat diets on plasma levels of NF-$\kappa$B-regulated inflammatory cytokines and angiogenic factors in men with prostate cancer. Cancer Prev Res (Phila) 2011 4(10):1590 - 1598

M. S. Morton, P. S. Chan, C. Cheng, N. Blacklock, A. Matos-Ferreira, L. Abranches-Monteiro, R. Correia, S. Lloyd, K. Griffiths. Lignans and isoflavonoids in plasma and prostatic fluid in men: Samples from Portugal, Hong Kong, and the United Kingdom. Prostate 1997 32(2):122 - 128

W. Demark-Wahnefried, D. T. Price, T. J. Polascik, C. N. Robertson, E. E. Anderson, D. F. Paulson, P. J. Walther, M. Gannon, R. T. Vollmer. Pilot study of dietary fat restriction and flaxseed supplementation in men with prostate cancer before surgery: Exploring the effects on hormonal levels, prostate-specific antigen, and histopathologic features. Urology 2001 58(1):47 - 52

Lin X, Switzer BR, Demark-Wahnefried W. Effect of mammalian lignans on the growth of prostate cancer cell lines. Anticancer Res. 2001 Nov-Dec;21(6A):3995-9.


Images thanks to National Cancer Institute via Wikimedia Commons


Why is there such a huge disparity in prostate cancer rates? The incidence of the clinically malignant prostate cancer is highest in African Americans, some 30-fold greater than in Japanese men, and 120 times greater than seen in Chinese men in Shanghai. Well, in general terms the ‘‘Western diet’’ is one in which animal protein and fat consumption is high, whereas the ‘‘fiber’’ intake is low. In contrast, the proportion of the total caloric intake from animal fat in the more vegetarian-style ‘‘Oriental diet’’ is low and the fiber content is higher. So maybe diet is playing a role in some of these diseases. But these healthier diets are not just low in animal proteins and fat and high in starch and fiber, they are also rich in weak plant estrogens, of which there are two types. We hear a lot about the soy isoflavones, but less about the other group lignans. This study found higher levels of lignans in the prostate fluids of men in countries with relatively low rates of prostate cancer and in vitro studies showed lignans can slow the growth of prostate cancer cells in a petri dish,so a pilot study was performed on flaxseed supplementation in men with prostate cancer before surgery. Why flaxseeds? Because while lignans are found throughout the plant kingdom, flax has up to 800 times more than any other food.  So they took a bunch of men with prostate cancer about a month before they were scheduled for surgery to get their prostates removed and started them on a relatively low fat diet with 3 tablespoons a day of ground flax seed to see what effect that might have on the growth of their tumors. Though they were skeptical that they would observe any differences in tumor biology in the diet-treated patients with such a short-term dietary intervention, they found significantly lower cancer proliferation rates and significantly higher rates of cancer cell death. That was compared to so-called historical controls, meaning compared to what the kind of growth one typically sees in their situation, not to actual randomized control group, but a few years later a study was published in which men were their own controls. These were men who just got their prostates biopsied and were scheduled to get repeat biopsies in six months. So they did the same thing, after the first biopsy, they reduced the fat in their diet and put them on ground flaxseeds to see if it made their repeat biopsy look any different. These were men with what's called PIN, which is like the prostate equivalent of ductal carcinoma in situ in the breast, precancerous changes. That's why they were getting repeat biopsies, to make sure it wasn't spreading. And this is what they found. Significant drop in PSA levels, which is a biomarker of prostate cell growth, drop in cholesterol, which is what one would expect with a lower fat diet and all that extra fiber, and the most important, a significant decrease in the cellular proliferation rate. In fact in two of the men, their PSA levels dropped so much they didn't even have to go through with the second biopsy. There hasn't been much research on this kind of prostatic hyperplasia, with only four epidemiologic studies reported at the time. They yielded varying findings, with increased risk associated with higher energy, protein, and animal product intake, and decreased risk related to the consumption of alcohol, fruit, and green and yellow vegetables—in sum, a low-fat, plant-based diet, high in phytoestrogens.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring watch the above video. This is just an approximation of the audio contributed by Jonathan Hodgson.

To help out on the site please email

Dr. Michael Greger

Doctor's Note

Slowing the Growth of Cancer is good, but how about Cancer Reversal Through Diet? In other words, if one plant could do that, what about a whole diet chocked full of plants? See my video series that goes from Ex Vivo Cancer Proliferation Bioassay (actually Engineering a Cure) to The Answer to the Pritikin Puzzle. And for benign prostate gland enlargement Prostate vs. Plants, and Prostate vs. a Plant-Based Diet (with background in Some Prostates Are Larger than Others).

What about for breast cancer? See Breast Cancer Survival and Lignan Intake. More on these wonderful seeds in Flax and Fecal Flora, my smoothies (A Better Breakfast), and the oldie but goodie Just the Flax, Ma’am. What about chia? Find out which is better in Flaxseeds vs. Chia Seeds.

Since the dietary intervention involved both reducing fat intake and flaxseed consumption, how do we know the flax had anything to do with it? That's the subject of the next video Was It the Flaxseed, Fat Restriction, or both?

For more context, check out my blog posts: Flaxseeds for Prostate CancerTreating Sensitive Skin From the Inside Out, and Flax and Breast Cancer Survival 

If you haven't yet, you can subscribe to my videos for free by clicking here.

  • Plantstrongdoc

    Obesity and obesity-related diseases increase the risk of prostate cancer (vegans weigh less than meat eaters), high concentration of IGF increase the risk of prostatecancer (higher level with animal fat and animal protein intake), dairy intake increase the risk of prostatecancer (IGF, high calcium intake). Lycopene has also been demonstated to have a positive effect in prostatic intraepithelial neoplasia. Will this make meat eating men reconsider?

    • Brian Humphrey

      Well said, Plantstrongoc. You know as well as I do regarding individuals who undergo a life altering event happens that makes a them reflect on their lifestyle and hopefully there diet. People ask all the time. How can I get this weight off? I tell them use positive words like fit and healthy and eat plants and lots of it :).

      • Plantstrongdoc

        and the good news is that you can improve your health even when you are ill, by switching to a plant based diet, and even avoid surgery. The body has great capacity to heal, when you remove the cause (SAD). Procedures and popping pills will not make anyone healthy.

    • Don Forrester MD

      It may make some men reconsider but in my experience it is more effective if you tailor your message to the individuals fears, goals and values. In looking at Dr. Greger’s videos on vegetables and cancer see… Greens and allium family are more effective in vitro then lycopene which is somewhat effective for prostate cancer but is even beat out by celery.

  • Thea

    Here’s a question that I have long had: Brown vs golden flax seeds? My store sells both in the bulk bins. Brown are cheaper. I would *guess* that brown are also healthier (have more anti-oxidents and more other good plant stuff???), but I don’t know. If anyone finds any info on this, I would be interested.

    I think both colors of flax seeds taste about the same, but I haven’t really done any side-by-side taste tests, so I don’t know for sure. I think that doing a side-by-side taste test would have to be done carefully: I believe that the brown ones are cheaper because they are a lot less popular. Since they are less popular, it is my *guess* that they are older, even in bulk bins. If that is true, I wonder how much brown might taste different just because it is going toward rancid.

    I struggle on which color to get. I currently get brown, but I wonder if I would get fresher ones just getting the popular color. It just occurred to me, I could probably ask the store how often they replace the seeds in each bin…

    • Shay Jensen

      Our Whole Foods store labels then as “whole flaxseed” (brown) and Golden Flaxseed. I should ask them what they mean by “whole”?

  • Rev Marshall Wright

    Unclear in your series on Flaxseed whether the max benefit is after grinding the seeds or consuming them whole ? Great series; an answer much appreciated.

    • Michael Greger M.D.

      Ground! Otherwise they might just pass right through us, come out the other end, and not do us any good!

  • akannapolis

    What does it mean higher ENERGY, protein, animal protein …

    What does the energy part mean in this video? What is dangerous energy?

  • Z

    What about prostatitis? Is there anything that can cure and heal people from prostatitis through diet/exercise?

  • Annamaria

    didn’t monsatan gmo flaxseed? how/where can we find non-gmo flaxseed?

  • lovestobevegan

    This delicious breakfast bowl makes it easy to get your daily 2 tablespoons of ground flaxseeds which provide the healthiest source of Omega-3 fatty acids. Additionally, flaxseeds provide the highest content of lignans (phytonutrients which seem to help in both breast cancer prevention and survival of any food, and are a great source of iron, zinc, copper, calcium,
    protein, potassium, magnesium, folate, soluble fiber (which can lower
    cholesterol and triglycerides), and boron (a trace mineral key for optimum bone health).

    Berry Berry Good Karma Bowl

    - ½ cup regular rolled oats
    - 1 cup water
    - ½ tsp Ceylon cinnamon
    - ⅛ tsp each, ground cloves, ground ginger, nutmeg
    - 1/3 cup blackberries
    - 1/3 cup organic* blueberries
    - 1/3 cup raspberries
    - 24 almonds
    - 2 tbsp flaxseed meal^

    Bring water to a boil and cook oats with spices and fruit (only if using frozen fruit). Lower heat and simmer oats to desired consistency. Add remaining ingredients to a bowl and top with cooked oats. Stir and top with a sprinkling of uncooked oats and dash cinnamon.

    *Conventional blueberries were found to have the residues of 52
    different pesticides so choose organic.

    ^Seeds need to be ground for proper digestion. A coffee or seed grinder works well or you can buy ground flaxseed meal.

    Bookmark my new Plant-Based Emporium Facebook page for all my latest recipes.

    ~Complements of lovestobevegan

  • Chris Hartley

    Interesting article

    “Evidence of prostate cancer, omega-3 link
    US scientists say they have confirmed a surprising 2011 study
    that found a higher risk of prostate cancer among men who consume
    omega-3 fatty acids, raising new questions about the safety of

    • Moonlight

      …but if you look at the data, you’ll see a number of flaws. This is not a causal link. Using the same logic, people who smoke and heavy drinkers are also more likely to develop PCa. Also, why do countries that traditionally consume a lot of fish not have increased incidence of PCa? Truly a rubbish study.

      • Person

        Correct and just FYI saying supplements cause this or that is fine but has little bearing on what the whole natural food from which the supplement is extracted or copied from does when consumed. Unhealthy chemical ridden food cannot be compared directly with the same food in its natural form – in the sense that if you add chemicals to anything it will cause any number of problems. Stop comparing apples to oranges….

  • MikeNewland

    Fantastic video about vegans etc living no longer and why on You Tube! So interesting the stages of the cascade into heart trouble. One needs to watch that lecture three times and take notes to grasp it all.

    May I ask a question on BPH? The idea seems to be to reduce conversion of testosterone into DHT – I think…..

    Flax seed lignans appears to be good for that and reduced average PSA lots in the small six month trial cited but betasitosterol as I understand it
    works the same way being also a 5 alpha reductase inhibitor. I think. Lots of trials on that.

    So are both together better yet?

    • MikeNewland

      I took betasitosterol 160mg a day for four months and could not see much effect. I then added 15 grams a day of flaxseed. After a month my average nocturia rate dropped from average 2.5 to around 1.2. Quite suddenly and it’s stayed down about two months now.

      I thought good prostate effect! But then I realised what was happening was that the flow at night from the kidneys had halved to a normal proportion of total daily flow. I conclude as a layman that this is an effect in normalising vasopressin secretion. Whatever the cause it’s a great result. I think it’s continued too long to be a placebo effect. I need less sleep.

      I read at that point the suggestion that betasitosterol should be taken on an empty stomach. I’d not seen that in the umpteen encouraging clinical trials about BPH. So I’m doing that (middle of night) but it’s a little too early to say whether it will get a result in substantially improving flow rate (which the trials reported).

      • MikeNewland

        Well I could not get any results with betasitosterol anywhichway but nothing works for everyone I understand.

        Flaxseed has continued to work in keeping down nocturia to once a night mostly. Quite a few months now. I take 15 g in the late evening.

        I can’t see any other explanation apart from the flaxseed. Unless it’s a coincidence. That would be a fluke.

  • apprin

    I was tested with a PSA of 11.1 and was having the typical lower back pain, urinary urgency with low volume, 3 – 4 bathroom trips per night, etc. I immediately went to a vegetarian (W/baked fish weekly) diet based upon cruciferous vegetables and within one year, PSA was 10.0, no lower back pain and no nightly bathroom trips and high volume with no urgency. I refuse needle biopsy, now proven to spread and worsen prostate cancer, and will go to Germany for transurethral hyperthermia if Color Power Doppler Scan reveals tumor(s). Why is American medical treatment (especially cancer) mired in the middle ages, except for the love of old money-generating procedures that are proven not to heal?

    • Thea

      apprin: Thanks for sharing your story. I think a story like this could be really helpful to someone who is trying to make decisions right now about their condition. Good luck.

      • apprin

        Thanks Thea … Am due for another PSA test. If symptoms (or lack thereof) are an indicator, My PSA will have fallen tremendously as nearly ALL symptoms have disappeared.

        • MikeNewland

          It’s a tiny select band who are willing to try things out like this and stick at it over a long period. Most people give up after a week and then complain it appears.
          It requires a scientist’s appetite for experiment and discovery does it not?

    • mark

      any update? did your psa drop again

  • Julia

    Does flax seeds really make your boobs grow?

    • MikeNewland

      No effect with this male!