Sign in. Skip auxiliary navigation Press Enter. Contact Us. Skip main navigation Press Enter. Toggle navigation. Search Options. Flaxseeds and Breast Cancer. Answer To understand potential effects of flaxseed and how they may affect breast cancer, it helps to understand what flaxseeds are, and why some consider them a concern for women with a history of breast cancer.
Flaxseed and phytoestrogens Flaxseed is the richest dietary source of lignans, a type of phytoestrogen. Phytoestrogens and breast cancer growth Phytoestrogens are somewhat similar to human estrogen, and some health experts have speculated that phytoestrogens might even act like human estrogen in the body. Phytoestrogens and breast cancer treatment Tamoxifen is a medication known as a selective estrogen receptor modulator, or SERM.
As a result, breast cancer cell growth is blocked One study in mice concluded that flaxseed inhibited the growth of human estrogen-dependent breast cancer, and strengthened the tumor-inhibitory effect of tamoxifen. Accessed March 24, Natural Medicines Comprehensive Database. High alpha-linolenic acid flaxseed Linum usitatissimum : some nutritional properties in humans. Br J Nutr ; Nutritional attributes of traditional flaxseed in healthy young adults.
Am J Clin Nutr ; Patisaul HB, Jefferson W. The pros and cons of phytoestrogens. Front Neuroendocrinol. Variability in anticancer lignan levels in flaxseed. Nutr Cancer ; These forms of estrogens, also known as xenoestrogens, have been linked to cancers.
The blogosphere has concluded that if flaxseed is estrogenic, then it must be as bad as the synthetic estrogens found in these toxic products. This is an oversimplification. It makes no sense to compare a plant-derived estrogen with a synthetically-derived estrogen. Unfortunately, this is shabby journalism, poor research, and a pure laziness to fact-check. I searched for medical studies that show the harmful effects of flaxseed on women and…found none.
These people, however, are in a vast minority. Bottom line: Be selective where you get your information from and whom you choose to trust. There is a fear of estrogen-containing foods, such as flaxseed, which is not only wrong and unjust but can also prevent you from reversing symptoms of estrogen dominance quickly and effectively. Just because you experience estrogen dominance, does not mean you should stop ingesting gentle plant-based estrogens. You need estrogen — as a woman you need it to have healthy breasts, butt, periods, glowing hair, and skin, etc.
The issue is not to cut out estrogen but to break it down properly. Most women with estrogen dominance do not suffer because of too much estrogen but because they are not breaking down and evacuating these estrogens well enough.
The only thing you want to remove from your life as much as possible are xenoestrogens which are synthetic estrogens that mimic estrogen without doing the right work. They are found in all commercial skin care products, perfumes, and cleaning products.
Having said that, I have met a few women they are the minority who have a paradoxical response to flaxseed — their estrogen dominance symptoms worsen. Among all foods, flaxseed contains the highest amount of lignans, a form of polyphenols, which are high in phytoestrogens. Polyphenols are a group of over phytochemicals which are naturally occurring micronutrients in plants. They are highly medicinal in nature and many supplement companies are cashing in on that.
Some of the polyphenols include quercetin found in apples , catechins in dark chocolate and cherries , lignans in flaxseed , resveratrol in pistachios, wine, and blueberries and curcumin in turmeric.
There are three types of phytoestrogens: Lignans enterolactone, enterodiol , isoflavones genistein, daidzein, biochanin A , and coumestans. Genistein and daidzein are found in soy, another phytoestrogen. When plant lignans are ingested, they can be metabolized by the intestinal bacteria in the large intestine into enterolactone.
Enterolactone is the bioactive form of phytoestrogen. It is enterolactone that binds to estrogen receptors, blocking and competing with estrogen which may help to reduce the growth of estrogenic cancers. One of the most fascinating chemical phenomena about lignans is that that can act as weak estrogen agonists promoter , partial agonists, or as antagonists blocker to endogenous estrogens internally produced and xenoestrogens which are synthetic estrogens found in much commercial skincare, cosmetic and cleaning products.
In short, flaxseed is an estrogenic adaptogen ; it can act as an estrogen amplifier or estrogen blocker depending on what the body needs. How fascinating is that?!
One powerful yet simple way to use flaxseed in your daily life is the seed rotation method — you can learn about it by downloading the Seed Rotation Starter Kit. The seed rotation method, however simple, has been one of the most popular methods used by our community. Because of the adaptogenic features of flaxseed, I see women both with too much estrogen and too little estrogen benefiting from this potent seed. There is a strong body of research to support the claim that flaxseed is hugely beneficial and can change lives.
Here are the reasons why I use and recommend flaxseed to women suffering from PMS, all the way to post-menopausal symptoms. The good news? Flaxseed has been proven to push the metabolism of these estrogens in the protective direction, hence helping with symptoms of estrogen dominance. The adaptogenic properties of flaxseed can help women in menopause and postmenopause as well. Because of its adaptogenic quality, flaxseed can attach itself to an estrogen receptor and block the growth of the cancer cells.
Flaxseed is a wonderful source of both insoluble and soluble fiber. It also helps to bulk up the stool which helps to create a well-formed stool. Chronic constipation is one of the causes of hormonal imbalances in women — which goes to say that a good, daily bowel movement is a prerequisite to good hormonal health.
Insoluble fiber also slows down sugar metabolism, helping balance blood sugar — one of the pillars of hormonal balance. Two tablespoons of freshly ground flaxseed per day will give you the above-mentioned benefits.
If that was not enough, flaxseed also contains the highest level of plant-based Omega 3. It can be beneficial but not for all — here is why.
Flaxseed contains the highest levels of alpha-linolenic acid ALA. This is true but not for all. If a person is depleted in any of these and many are , then flaxseed alone might not be the best source of the highly anti-inflammatory Omega 3.
On the other hand, if the person is well nourished, then it is true — flaxseed can be a great source of Omega 3. Cardiovascular health can be a concern in postmenopausal women. This study concluded: In conclusion, a high intake of phytoestrogens in postmenopausal women appears to be associated with a favorable metabolic cardiovascular risk profile.
A few tips on how to use flaxseed to reap its medicinal properties:. Grinding flaxseed makes lignans more bioavailable. We get many emails from our readers confused why I would suggest flaxseed.
As you can tell from the above narratives, why would I not?! Having said that, I have met women who had, what is called, a paradoxical response to flaxseed. Instead of feeling better, their symptoms worsened. It is not fully understood why some women experience an adverse reaction from digestive issues to getting worse PMS, painful breasts and heavier periods to flaxseed.
I do not work with men so I have limited experience and feedback from men. The little research available shows that men might not be benefiting from flaxseed as much as women do. One study points out elevated prostate cancer risk and infertility. I searched for medical studies that show harmful effects of flaxseed on women and found none. I did, however, find a number of blogs that make such claims.
If they improve — great! Keep going; you can use flaxseed in the long term. If you feel worse, stop it immediately. In Overcoming Estrogen Dominance , my goal is to empower and give you the tools to take control of your hormones and health. The symptoms range from lumpy and fibrocystic breasts to thyroid nodules, hot flashes , fibroids, uterine polyps, painful, heavy or irregular periods to infertility and miscarriages, from mood swings to insomnia, weight gain to fatigue.
They feel unheard, helpless, with no control over their bodies or the underlying issues that are causing their debilitating symptoms. This is particularly true for women who are experiencing the symptoms of hormone imbalance.
In Overcoming Estrogen Dominance, I hope to show that those extreme interventions are often unnecessary, and to give women a roadmap to ease and erase their symptoms using food, herbs, supplements and natural protocols to re-balance hormones.
My goal is to help reverse the impact of estrogen dominance naturally, helping you lead a symptom-free life, without fear. To get your copy of Overcoming Estrogen Dominance , go here. Horn-Ross, Pamela L. Atkinson, et al. Franco, Oscar H, et al. National Library of Medicine, 21 June Dodin, et al.
Chen, Jianmin, et al. Bingham, Sheila A, et al. National Library of Medicine, 3 May A controversial issue, however, has been the estrogen-like effects of lignans, and concern that flax consumption may fuel disorders linked to excess estrogen, including estrogen-receptive breast, uterine and ovarian cancers. Although phytoestrogens — such as lignans — are structurally similar to the estrogen made by the body, eating more flax does not appear to increase blood levels of this hormone.
In fact, a review of available human research, published in the May issue of "Integrative Cancer Therapies," concluded that flaxseed consumption in women either had no impact, or caused a decrease in blood levels of estrogen. Additionally, one of these trials showed that 2 tablespoons of ground flaxseed daily reduced levels in the women who were overweight, but did not significantly decrease estrogen levels in normal weight postmenopausal women.
Phytoestrogens do not need to reduce estrogen levels in order to exert their health effects. For example, lignan byproducts are known to bind to the estrogen receptors found in body tissues, shifting estrogen production to weaker forms which do not enhance cancer cell growth. The lignans found in flax may also inhibit aromatase , an enzyme which produces estrogen.
Because phytoestrogens are structurally similar to estrogen, they can also mimic estrogen and help reduce the risk of conditions associated with low estrogen levels, such as osteoporosis and heart disease. Many people with cancer choose to make some changes in their eating habits while subjected to conventional, like chemotherapy.
These less-conventional treatments may include diets with food that has proper nutritional characteristics to help fight the disease. Flaxseed has been one of the most studied foods regarding the possible relation to breast cancer. Some experimental studies in animals have been done but few progressed to clinical trials. To review the effect flaxseed may have in breast cancer, we conducted a bibliography research using sources from PubMed , and websites of institutions like Cancer Research UK and the WHO.
The keywords used in the research were as follows: cancer, flaxseed, lignan, breast cancer , and nutrition. Breast cancer is considered as one of the most common cancers with the highest number of deaths worldwide.
According to the WHO, it was estimated that in , more than 1. Of these, approximately , died and in Europe, during the same year, more than , new cases were diagnosed and approximately , women died 1 , 10 , In , in the United Kingdom, there were approximately 55, new cases of breast cancer men and about 54, women , of which approximately were diagnosed daily with approximately 11, deaths due to this kind of cancer.
It is considered that one in eight women will be diagnosed with breast cancer during their lifetime In , in Portugal, approximately 27, people died of cancer, with 1, of the victims being women with breast cancer. Also, approximately 6, new cases of breast cancer were diagnosed in women 2. There are several factors that can be associated with breast cancer, such as gender, bad eating habits and respective lifestyles, family history, alcohol or tobacco consumption, lack of breast feeding, hormone treatments, overweight, and obesity, among others 10 , After being diagnosed, many patients with breast cancer decide to change their eating habits and respective lifestyles 12 , Flax Linum usitatissimum , also known as linseed, belongs to the Linaceae family which originates from Europe, Asia, and the Mediterranean region.
Flaxseed can be divided in two species: brown and golden. Golden flax develops in very cold climates, while brown flax develops in warmer and more humid climates.
The latter must be ground to be better digested and absorbed by the body, thus increasing the bioavailability of the nutrients. Flaxseeds are rich in fiber and are suggested for situations of constipation, as they help to improve the intestinal function.
They have omega-3 fatty acids that promote the reduction of cholesterol levels, thus preventing cardiovascular diseases. Additionally, they are still a good source of magnesium, phosphorus, manganese, vitamin B1, selenium, and zinc.
Although they are defined as one of the richest plant sources in omega-3 fatty acids, these seeds are also characterized by their lignan content. Although lignans are found in a variety of vegetable sources, such as whole grains, sesame seeds, vegetables, and fruits, flaxseeds have approximately times more lignans than other foods 9 , 17 , Lignans are phytoestrogens that relieve the symptoms of menopause and can balance the effects of estrogen in the body by connecting to their receptors, as they have a very similar chemical structure as to an estrogen molecule After SDG lignan ingestion, bacteria in the colon act by converting the lignan into mammalian lignans, enterolactone, and enterodiol.
These are structurally similar to estrogen, and have antioxidant activity and a weak estrogenic action Figure 1. In our body, the biological active form of estrogen is estradiol, which is oxidized mainly in the liver to estrone. Women who produce more 16OHE1 are likely to have an increased risk of breast cancer Two clinical trials concluded that 28 postmenopausal women, who followed a diet including 10 or 25 g of ground flaxseed for 7 or 16 weeks, witnessed an increased level of excretion of 2OHE1 in their urine, without an increase in the excretion of 16OHE1.
These studies imply that flaxseed can have some protective effects in postmenopausal women Polyunsaturated fatty acids PUFAs can be composed of omega-3 and omega Linolenic acid and arachidonic acid AA are the main components of omega Omega-3 and ALA are also constituents of flaxseed.
Flaxseed is considered as the best plant source of the essential omega-3 fatty acid. Studies suggest that the omega-3 fatty acid may have anticancer properties while omega-6 fatty acid can contribute to the development of cancer. Currently, in a regular diet, there is a higher amount of omega-3, than omega-6 29 , Studies have revealed that PUFA omega-3 ingestion is associated with the reduction of risk of breast cancer In animal studies, the ALAs have been shown to be able to suppress the growth, size, and proliferation of cancer cells.
An increase in the death of these cells has also been observed 32 , It can be used as an adjuvant therapy for breast cancer or metastatic breast cancer. It is a type of hormone therapy that is done during 5—10 years with several side effects 34 — According to experimental studies, flaxseed does not have any type of interaction with drugs used in breast cancer treatments and can provide an additional protective effect when consumed along with the treatment.
Until now, there are no clinical trials that can prove the benefits that flaxseed ingestion can have in women with breast cancer during tamoxifen therapy These mice were injected with MCF-7 tumors and fed with different diets. The diets had 20—25 g of ground flaxseed, a tamoxifen pill 5 mg or both.
Tumor growth was monitored weekly. There are currently no known results from clinical trials regarding flaxseed ingestion during tamoxifen therapy In animal studies with mice injected with breast tumor cells, feeding them with flaxseed caused a decrease in tumor incidence, number, and size.
A research group from the University of Toronto has also demonstrated that ground flaxseed has an effective anticancer activity. Their experimental study was conducted in mice to which tumors were administered, along with the introduction in their diet of a mixture of lignan.
The result was a decrease in the tumor load due to the presence of flaxseed and lignan SDG in the mice diet 43 — Recently, the same research group injected another mice group with human breast tumor cells. Lignans also contribute to the decrease of breast cancer risk. Vegetarians have a higher level of lignan ingestion, meaning that their breast cancer risk is lower than that of omnivores This study did not show any effects regarding flaxseed on the aromatase inhibitor activity in selected breast tumor characteristics and serum steroid hormone levels 9.
Further studies are needed to support a possible interaction between flaxseed intake and the aromatase inhibitor——anastrozole. This risk decrease may be related to a reduction in inflammation, since the presence of large amounts of lignans can lead to a decrease in several inflammatory markers 52 , In two meta-analysis studies, it was found that a higher intake of lignans from dietary sources was associated with a significant reduction in postmenopausal breast cancer risk 54 , In a case-control study, the highest lignan consumption was associated with significantly lower postmenopausal breast cancer mortality but that association did not happen relatively to premenopausal breast cancer mortality A case-control study using the Ontario cancer registry database consisted of a random sample of women diagnosed with breast cancer, with the aim of analyzing the phytoestrogen intake isoflavones and lignans and their association with breast cancer risk.
A food-frequency questionnaire was used, which also included foods rich in phytoestrogens.
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