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Flaxseed & breast cancer: A systematic review

nnguyen Member Posts: 52
edited June 2022 in Alternative Medicine

From SABCS 2021 Publication Number: P1-09-04

Flaxseed & breast cancer: A systematic review

Rui Wang1, Mingxiao Yang2, Iris Zhi2 and Ting Bao1. 1Memorial Sloan Kettering Cancer Center, Montvale,
NJ;2Memorial Sloan Kettering Cancer Center, New York, NY

R. Wang: None. M. Yang: None. I. Zhi: None. T. Bao: None.

Background: Flaxseed has been extensively studied in in vitro and in vivo models for possible association
with reducing the risk of breast cancer. Clinical trials have been limited. There has been confusion
regarding whether it is safe and beneficial for breast cancer survivors to take flaxseed. Therefore, we
conducted a systematic review to evaluate the existing randomized controlled trial to understand the
safety and efficacy of using flaxseed for symptom control and reducing the risk of recurrence among
breast cancer survivors.

Patients and Methods: We conducted a literature search of English language
publications in MEDLINE, EMBASE, and Cochrane from the databases' inception to May 2021 using the
keywords flaxseed, breast cancer, randomized clinical trial, and human studies. Results: We identified
three randomized controlled trials (RCT) that include patients with a history of breast cancer. Sample
size ranged from 24 to 178 patients and treatment duration ranged from 13 to 42 days. The primary end
points were hot flash severity (one study) and tumor biomarkers (two studies). There was no statistically
significant reduction in mean hot flash score in the flaxseed group compared to the placebo group. One
study showed a statistically significant reduction in Ki-67 (34.2%; P=0.001) and in c-erbB2 expression
(71.0%; P=0.003), and an increase in apoptosis (30.7%; P=0.007) in the group that received flaxseed, but
not in the placebo group. On the contrary, another study showed no difference in Ki-67, caspase, the Ki-
67/caspase ratio, and Estrogen-receptor β. Two studies reported mild adverse events as shown in Table
1. None of the studies assessed the change in estrogen level. Risk of bias assessment showed that the
overall risk of bias associated with the included studies is moderate to high. The high risk of bias
originates from lack of blinding of participants and personnel.

Conclusion: Current clinical research in
breast cancer survivors is too limited to recommend flaxseed for cancer prevention. Flaxseed appears to
be safe with mild side effects, however, the effect of flaxseed on estrogen concentration has not been


  • homemom
    homemom Member Posts: 788
    edited February 2022

    So I recently bought flaxseed bread. Good? Not good?

  • nnguyen
    nnguyen Member Posts: 52
    edited February 2022

    Though it seems flaxseed seems to have multiple benefits but it is a source of plant based estrogen. Flaxseeds also influence er/pr ratio during luteal phase. Since you are ER and PR positive and especially taking anastrozole to reduce estrogen level, I would say don't risk taking it.

  • threetree
    threetree Member Posts: 1,157
    edited February 2022

    HomeMom - You might want to read this for some more info:

  • rah2464
    rah2464 Member Posts: 1,192
    edited February 2022

    My MO ( who is very careful about what I am allowed to take) is ok with me having a couple tablespoons of ground flaxseed on my oatmeal daily.

  • threetree
    threetree Member Posts: 1,157
    edited February 2022

    I've never discussed it with the oncologist I see, but like Rah, I take 2 tablespoons every day and have for 2.5-3 years now. These estrogenic foods like soy and flax seem to work both ways, but mainly for the good. My understanding is that "whole soy" as in tofu, soy beans, soy milk, etc. is fine. It is the various extracts of soy components (often put in capsules) that are the problem. It is also my understanding that whole flax seed at about 2 to 2.5 tablespoons per day is actually beneficial. I started going strong with it just before radiation, as there are some thoughts out there that it is radio protective in some way in addition to other benefits. I have to say, I had no major problems with radiation, only minor things, so I have to wonder if the flax maybe played a role. My further understanding is that we have two primary estrogen receptors, alpha and beta. Plant estrogens affect them differently than animal estrogen and it depends on which receptor a given estrogen relates to when it comes to it's positive or negative effect on ER/PR+ breast cancer. Anything in the extreme can be bad for us, but in reasonable amounts, I've been under the impression that things like soy and flax are just fine, and likely beneficial. Just because something is estrogenic, doesn't mean it's bad. It could go either way.

  • marciam
    marciam Member Posts: 83
    edited February 2022

    Hi Three tree;

    Over 11 years ago I used flax seed oil combined with tamoxifen to help heal my siezures . I developed seizures as a result of menopause. after I went through stage three breast cancer I was left with nothing to control the seizures. I tried the flex seed oil Budwig protocol and lo and behold the seizures disappeared. I asked my oncologist to measure the amount of estradiol which is the evil estrogen that accounts for ER positive breast cancer. It was higher than it was when I was taking pure estradiol in bio identical hormones which caused the cancer in the first place. So I withdrew from flaxseed oil. However now I use CBD oil to control the seizures and my estrogen levels are higher than when I developed breast cancer in the first place over 10. I think you’re right that it depends on whether it’s plant-based and it’s a natural form of food versus something chemically manufacture to create estradiol. I am 12 years out from stage three but I had a brain tumor in 2012 and had to have radiation and resetection, ie brain surgery . It was an ordeal .

    Estrogen is a complex hormone . If you take an AI or tamoxifen then you should be ok . If you don’t use them I’d ask your Dr, but I think plant based foods are ok . There are many good studies out there on soy . In a vegan and eat lots of tufu and it’s safe !
    be in touch


  • threetree
    threetree Member Posts: 1,157
    edited February 2022

    MarciaM - Wow, seizures brought on by menopause! That must be awful, I'm so sorry. I've never heard of that before. Have they not gone away without active treatment of some kind? Is this a permanent thing for you? I sure hope not.

    Interesting too about the Budwig protocol. I read a little about Dr. Budwig some time ago, and it's actually a shame that her legacy now seems to be that of a "cancer quack". She actually did some interesting work early on, looking into fats seemingly before others did, and I understand that that led her to cancer research in some way. While I wouldn't just subscribe to her overall cancer protocol, I do think there are some things in it that are valid - things that are encouraged today. She advocated for people to take daily walks; well that's something they tell us all to do now. She also suggested sunbathing; now we are told to get lots of vitamin D. The flax seed seems to be the other thing that I think she might have been "right" about. I had started with the flaxseed primarily as a radiation damage preventive thing, based on some things that I read, but later when I read about some of the Budwig protocol, I noticed that she recommended that people have some flax seed several times a day, mixed in cottage cheese, although yogurt could be substituted. I found that fascinating, because I'd been having flax seed on my morning cereal and in my afternoon bowl of yogurt for months at that point. Apparently, Dr. Budwig just never published any of her findings in any scholarly journals and only provided anecdotes of people who said they were "cured" by using her method. It really does seem to be a shame, because it looks like in some ways she was at least initially onto some things that are now pretty routine suggestions about what might help in addition to the regular medical treatment.

    Also of interest sre the estradiol levels you mentioned. The oncologist I see won't measure them and says it just "not done", so I have no idea what mine are. I take Letrozole and then try to walk, eat well, etc. I don't know what more I can do at this point. I can't help but think that flaxseed is generally a positive though, in moderate amounts, and at this point I see no reason to stop with my 2 - 2.5 tablespoons a day. I read that that is the usual amount that was used in studies that showed positive effects for various conditions. I've never tried CBD oil and don't know that I will. I remember back in the old hippie days (I'm 69) it was such a taboo, that I don't know if I can ever bring myself around to the idea that it's legal now (at least in my state). I do have an old friend though, who has been going strong for 16 years after a de novo stage 4 pancreatic cancer diagnosis, and I know some years ago she started using pot in one form or another. Maybe I should talk to her more about that. I don't have anything like major pain or seizures though (so far) thank goodness, but who knows what's in store down the road.

    Well, Marica, your comments were very interesting and helpful and I am truly sorry to hear about some of the things you mentioned. I wish you as much luck as there is out there "in the universe" for your future!

  • homemom
    homemom Member Posts: 788
    edited May 2022

    I just had an appointment with a nutritionist and she told me plant soy has not been proven to mimic our body's estrogen. She made the statement that if it were, women in Asia would be rampet with ER + breast cancer. Makes sense

  • jrnj
    jrnj Member Posts: 407
    edited May 2022

    homemom, sorry for the dumb question, but what does plant soy have to do with flaxseed?

  • marciam
    marciam Member Posts: 83
    edited June 2022

    Hi there Dear

    Hi there dear . I hadn’t got back to breast in a long time. I love the fact that you’re using flaxseed oil and I don’t use it because I use CBD for the seizures and it really works miracles for me. Did you know that on the NIH website and the national cancer institute website both have small studies conducted that prove that CBD is preventative and it works against breast cancer! I think that’s really cool. I also liked that I got into Dr. Budwigs research although she couldn’t participate in studies she was an early pioneer doing something out of the norm. But I do know that if your friend healed totally of pancreatic cancer using marijuana medical marijuana that are termed these days that you should look into it. I do mostly CBD and I take a tiny bit of maybe less than a milligram to help me go to sleep at night of THC combined with CBD. I’ve had no issues with seizures since doing both flaxseed oil and CBD oil. Absolutely none! And my health is good I’ve been 10 years out from stage four cancer doing some alternatives and I do a lot of juices

    I’ve written a vegan cookbook if you’re interested in getting one you can send me an email through the forms. I love doing vegan cooking , gardening and my life has improved a lot since the diagnosis. I must be honest and admit that I lost a lot of friends that couldn’t relate to the multiple illnesses I’ve had. a lot of side effects confused my old friends who all left me pretty much . Im Still here!

    Now I’ve recently been diagnosed with colitis and microscopic type and then a new problem with an ovarian cyst that seems to be growing and may have to have surgery. I’m wondering if it’s the Evista I’ve been on for bone loss? my oncologist wants me to have surgery. It’s a growing thing . I guess I will ?
    my preference is to do all natural healing .

    Wishing you good health in all ways

    Thanks for asking about me !
    Marcia M