Flax Myth: Do Not Eat Flax Seed

By Jayton Miller

Flaxseed is one of the most terrible “so called health foods” you can eat. Compounds in flaxseeds work against your health. 

I put out a video 6 months ago about this subject, reporting on the highly estrogenic activity of these flaxseed compounds, and that video which I’ll link to here, has since accumulated many hundreds of thousands of views. 

A lot of people obviously did not believe the medical research proof that I merely reported. I’m not sure why they wouldn’t believe the cold hard evidence. So I read a lot of the comments and saw a couple distinct patterns of main objections. 

In this article I’m going to explain a bit further the anti-health effects of consuming flax seeds, from making prostate & breast cancer tumor growth more aggressive, to inhibition of reproductive hormone production, to even large scale thyroid disruption. 

So buckle up and get ready, because we’re about to Bust this Flaxseed myth once and for all!

Key Takeaways:

First off, if you haven’t already heard my spiel on what true health really is then I suggest learning more about the Thermo Diet here, as well as checking out some of the other articles we have here on the UMZU blog. It’s important to identify what I mean by the word and the idea of “Good Health.” so that we are on the same page as we are discussing this topic. I personally view health in the human body from a systemic view. In doing so, I see the body as one whole system that operates optimally only when two major conditions are met. 

  1. Correct Nutrient Deficiencies - All micronutrient deficiencies are corrected (therefore, anything that causes micronutrient deficiencies would be anti-health)
  2. The Body Is Hormonally Balanced - Meaning the stress hormones (like cortisol, estrogen, prolactin, and SHBG) are low, while protective hormones like all of the reproductive hormones and thyroid hormones are high.

Anyone disagreeing that the body should not have adequate micronutrient levels to operate properly, or that the body should have higher stress hormones and low reproductive hormones, well, then our understanding of what true health is simply does not match up.

Read More: The War On Micronutrients | The Battle You Never Knew You Were Fighting

Why Are Flaxseeds Not Healthy?:

Flax Seeds Aren't Healthy

Now that we’ve identified what true health is, I’m going to show you exactly why Flaxseeds are NOT healthy in the slightest and why you should avoid their consumption at all costs. 

Like I mentioned earlier, flaxseeds contain certain compounds that specifically have powerful effects on hormone disruption, in both reproductive hormones as well as thyroid. They also have been shown in the medical research to accelerate cancerous tumor growth in male and female studies. 

Pursuant to that information, I’m going to break this article into two distinct sections. First I will cover the hormone disruption that has been proven to occur with flaxseed consumption, second I’ll wrap this up going over the cancer related research. 

Anti-Health Compounds In Flaxseeds:

It’s important we first cover the breakdown of a handful of key compounds that are found in all flaxseeds. These are critical to understand. 

  1. Lignans: Lignans are phytoestrogens that have been shown to directly inhibit steroid synthesis while increasing estrogenic activity in the body. Flaxseeds are the richest known nutritional source of lignans.
  2. Genistein: Genistein is an isoflavone phytoestrogen that also increases estrogenic activity in the body while inhibiting important reproductive functions such as spermatogenesis and steroid hormone synthesis in men, while increasing uterine weight and and causing endocrine dysfunction in the female reproductive systems in women.
  3. Daidzein: Daidzein is another common isoflavone phytoestrogen that has been shown in the research to have similar anti-reproductive effects in both men and women.

I’m going to reference those compounds quite a bit here in this recap of the research on flax seeds, so I wanted to make sure you understood what they were. The health, or anti health, effects of food are entirely dependent on the effects of certain compounds in that food on the body. Don’t fall into the thought trap that just because something is natural, that means it’s good. You must respect nature. It is not something to be treated as if it is subservient to us humans. This attitude is akin to walking up to a bear as if you’re entitled to be able to pet it, while expecting no adverse consequences. 

It is arrogant for a human to believe that just because something grows in nature that it is subservient to the human body. The plant kingdom can be just as powerful, either in a positive or negative way as any animal. Respect plants and the effects of the compounds in them the same way you would respect an animal. Many plants have evolved incredible defenses against being eaten. It’s pretty obvious to me, that the anti nutrient and anti reproductive effects of most seeds are a natural evolutionary defense against animals eating them and incorporating them into regular diets. Seeds are literally the “seed” of a plant’s life. They must protect themselves in order to continue their cyclical process of life. 

Now because I know you want the evidence, let’s dig into the meat and potatoes here…

Read More: How To Get Rid Of Estrogen | The All Encompassing Guide


Part 1

Flaxseeds have been shown over and over again in scientific peer reviewed research to be antagonistic to the protective hormones of the body. Flaxseeds are known to interfere with steroid hormone metabolism and are currently the richest source of lignans that we know of. 

DHT is one of the major male reproductive hormones in the male body, known as the “big brother” of testosterone, this hormone is responsible for male characteristics such as defined jaw lines, body hair, muscle strength, and much more. In order to create DHT the body has to convert testosterone into DHT using the 5-a reductase enzyme. It just so happens that the lignans and isoflavones found in flaxseeds have been shown to effectively lower 5-a reductase activity. This is horrible for men’s reproductive health!

This study showed that flaxseed supplementation led to a significant decrease in cholesterol, testosterone, and free androgens. Another study showed the effects of genistein being able to inhibit the functioning of the leydig cells and lowers spermatogenesis. 

The effects that flaxseeds have on reproductive hormones cannot be overstated, but it  isn’t just limited to  reproductive hormones. These seeds have a pronounced effect on your thyroids  ability to properly produce thyroid hormone for your body as well. 

This study showed that in male mice exposed to flaxseed during breastfeeding as they aged they had lower thyroid hormone levels and inhibited deiodinase activity. 


Flaxseeds & Cancer

These hormonal effects are not the only thing that flaxseeds can affect. As I mentioned earlier they have a distinct effect on several types of cancers. This study showed that flaxseed oil has the potential to make prostate tumors MORE AGGRESSIVE. That is insane!

Genistien has been shown in several studies to increase the growth of estrogen dependent mammary tumors along with genital tract tumors!

This is just a small glimpse of the mountains of research that has been done on these chemicals and what they have the ability to do in the human body. Voluntarily ingesting these naturally occurring compounds can wreak havoc on your health, and taking steps to mitigate your exposure and ingestion of these is going to pay dividends when it comes to your health. 

The Proposed Benefits Of FlaxSeeds:

Many of the “so-called” benefits of Flaxseeds go hand-in-hand with their detriments. The three main proposed benefits of flaxseeds are:

  1. High Omega-3 Content

  2. Great source of soluble & insoluble fiber

  3. May Lower “Bad” Cholesterol levels

  1. The Omega-3 Fatty acids are not healthy for you. The polyunsaturated fats including both omega-3 and omega-6 fatty acids are very unstable due to the high double bond quantity. When we consume polyunsaturated fats and our cells use them for energy they have a very high likelihood of oxidizing and releasing free radicals. This causes oxidative stress in our body and is associated with a whole host of health issues. You can check out our article, “The Nonessential, Essential Fatty Acids” to learn more about the subject.
  2. Insoluble fiber like that found from plants can help to add bulk to our digestive tract and “get things moving”. But this is a double-edged sword as too much fiber will lead to fermentation by the bacteria in our large intestine which can lead to bacterial overgrowth and actually worsen our digestion. I personally recommend consuming insoluble fiber from raw carrots, cooked bamboo shoots or mushrooms. Soluble fiber on the other hand is easily fermentable and does not help to add bulk to your stool, so it is generally best to be avoided especially if you have digestive problems.
  1. There is no such thing as “bad” cholesterol, this is a drastic oversimplification. Moreso, it’s been proven that the so-called “bad” cholesterol does not cause heart disease or atherosclerosis, but having elevated “bad” cholesterol is a warning sign that you are at risk for these health conditions. In older populations having higher cholesterol levels is actually associated with lower all-cause mortality and likely signifies a more active thyroid and higher “protective” hormonal levels like testosterone and progesterone.

If you want to learn how to eat for optimal health to skyrocket your energy levels boost your testosterone or progesterone levels, fix your digestion and ultimately heal your body check out our Thermo Diet Program. The Thermo Diet Program is our method of eating in order to optimize your metabolism to rid your body of unnecessary stresses and provide your body with the energy it needs to heal.

The Thermo Diet


This article has been written in order to inform you of what even naturally occurring compounds in plants have the capability of doing in the human body. At the very least we at UMZU want to ensure that you are making informed decisions about how you take care of your body, and how to do it in the best way possible. 

Cheers to your health!

https://www.ncbi.nlm.nih.gov/pubmed/10325492 (Shows interference with bioavailability and and steroid metabolism, and have estrogenic activity.Also states flaxseed is the richest source of these lignans.)

https://www.ncbi.nlm.nih.gov/pubmed/7490559 (shows use of dietary lignans and isoflavones to reduce 5 alpha reductase.)

https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2752973/ (Shows a significant reduction in androgen levels due to  flaxseed supplementation.)

https://www.ncbi.nlm.nih.gov/pubmed/19064574 (This study showed a significant decrease in serum cholesterol, which we know later leads to decreased steroid production.)

https://www.ncbi.nlm.nih.gov/pubmed/18328014 (Shows lowered total and ldl cholesterol in postmenopausal women.)

https://www.ncbi.nlm.nih.gov/pubmed/11445478 (Shows significant decrease in cholesterol, testosterone, and free androgens.)

https://www.ncbi.nlm.nih.gov/pubmed/2826899 (Shows one of the lignans found in flaxseed enterolactone has a negative correlation with testosterone, as well as a positive correlation with SHBG.)

https://www.ncbi.nlm.nih.gov/pubmed/1314077 (Although support it for having a slight chance of anti cancer effects this study shows these compounds are able to compete for the type 2 estrogen receptor.)

https://www.ncbi.nlm.nih.gov/pubmed/22943974 (shows flax increase 17 beta estradiol but has no effect on how the penis develops.)

https://www.ncbi.nlm.nih.gov/pubmed/26337632 (Lactating rats fed flax lead to hypercorticosteronaemia in adult male offspring.)

https://www.ncbi.nlm.nih.gov/pubmed/21448850 (Shows exposure during breast feeding of rats can have an impact on thyroid hormone metabolism in adult male offspring.)

https://www.tandfonline.com/doi/abs/10.1080/01635580801971864 (Shows flax lowers sex steroid hormone in obese women.)

https://www.tandfonline.com/doi/abs/10.1207/S15327914nc391_8 (Shows decrease in 17 beta estradiol and estrone sulfate but increase in prolactin in postmenopausal women.)

https://www.tandfonline.com/doi/abs/10.1080/00984109909350177 (Shows flaxseed potential to alter reproduction in a dose dependent manner)

https://www.ncbi.nlm.nih.gov/pubmed/25163581 (This case study showed a woman went into anaphylactic shock after ingesting linseed containing bread.)

https://www.ncbi.nlm.nih.gov/pubmed/23550019 (Endocrine disruptors and phytoestrogen underlie a suit of adverse human health effects.

https://www.ncbi.nlm.nih.gov/pubmed/12943716 (Consumption of phytoestrogens alter hormone sensitive hypothalamic brain volumes in mice.)

https://www.sciencedirect.com/science/article/pii/0022473187902007 (Shows an inverse correlation with high fiber to excretion of estrogen.)

https://www.sciencedirect.com/science/article/pii/096007609390022O (Shows inhibition of aromatase.)

http://joe.endocrinology-journals.org/content/147/2/295.short (Shows that lignans and isoflavones inhibit 5a-reductase.)

https://www.ncbi.nlm.nih.gov/pubmed/8594308 (Phytoestrogens modulate sex steroid binding protein and effect the delivery of this protein to sex steroid dependent cells.)

https://www.ncbi.nlm.nih.gov/pubmed/29699226 (Shows a decrease in LH, FSH, and estradiol in postmenopausal women.)

https://www.ncbi.nlm.nih.gov/pubmed/9039826 (Shows genistein (phytoestrogen) causes increase in uterine weight and has an effect on mammary glands and HPA axis.)

https://www.ncbi.nlm.nih.gov/pubmed/12629420 (Perinatal exposure to genistein had lasting alterations in the masculinization of the reproductive system in rats.)

https://www.ncbi.nlm.nih.gov/pubmed/10022277 (Shows phytoestrogens are endocrine disruptors just like any exogenous form of hormones.)

https://www.ncbi.nlm.nih.gov/pubmed/11014247 (Showed neonatal exposure to rats lead to a group of infertile and non mating adult males.)

https://www.ncbi.nlm.nih.gov/pubmed/11738518 (Shows genistein has effects on estrogen sensitive tissues in both male and female rats.)

https://www.ncbi.nlm.nih.gov/pubmed/17250991 (Shows genistein has adverse effect on the female reproductive system in mice.)

https://www.ncbi.nlm.nih.gov/pubmed/20381596 (Isoflavone exposure results in increased estrogen sensitivity in female rats.)

http://joe.endocrinology-journals.org/content/187/1/117.short ( Shows genistein influences spermatogenesis and significantly inhibits Leydig cell steroidogenesis.)

https://rbej.biomedcentral.com/articles/10.1186/1477-7827-2-5 (Shows a decrease in androgen receptor production in the prostate of male rats, I wish they would have looked at the entire body rather than just the prostate.)

https://www.sciencedirect.com/science/article/pii/S0303720700004226 (Shows phytoestrogen have an inhibitory effect on the 17 Beta hydroxysteroid dehydrogenase (an enzyme necessary for proper steroidogenesis of DHEA and T.)

https://www.sciencedirect.com/science/article/pii/S0303720701006633 (This study showed a down regulation of both androgen and estrogen receptors.)

https://www.bprcem.com/article/S1521-690X(05)00070-9/fulltext (Shows possibility of phytoestrogens and other EDC’s possibly inhibiting steroidogenesis.)

https://academic.oup.com/humrep/article/17/3/589/642181 (Shows genistein directly inhibits steroid synthesis.)

https://www.sciencedirect.com/science/article/pii/S0890623807002365 (Shows genistein and diadzen have a direct impact on progesterone synthesis.)

https://www.sciencedirect.com/science/article/pii/S0161813X08001289 (Shows impairment of female reproductive system when neonates were exposed due to decreased stimulation of GnRH neorons.)

https://link.springer.com/article/10.1007/s11154-007-9048-y ( Shows neonatal exposure can cause  abnormal sexual differentiation, disrupted reproductive function, or inappropriate sexual behavior may be detected later in life.)

http://journals.sagepub.com/doi/abs/10.3181/00379727-208-43836 (Shows lactational exposure can alter neuroendocrine development in both male and female rats.)

https://www.sciencedirect.com/science/article/abs/pii/S0031938404005347 (Shows genistein exposure in male rats caused a decrease in agressiveness and increase in defensiveness, this compound literally takes away the psychological masculinity of male rodents!!)

https://academic.oup.com/endo/article/143/8/2913/2989539 (Shows phytoestrpgens have a significant impact on testi function.)

https://www.sciencedirect.com/science/article/pii/S0165380699000383 (Phytoestrogens alter the hypothalamic calbinin d28k levels in neonates and thus do not allow for prgrammed cell death because of buffered effect of calcium.)

https://synapse.koreamed.org/DOIx.php?id=10.3345/kjp.2012.55.8.265 (States significant effects of phytoestrogen on sexual development, including altered pubertal timing, impaired estrous cyclicity and ovarian function, and altered function of the HPG axis.)

http://journals.sagepub.com/doi/abs/10.3181/00379727-208-43832 (Shows effect of prenatal exposure and sexual differientiation in rats.)

https://www.sciencedirect.com/science/article/pii/S0892036201001921 (States even small exposure of these phytoestrogens can alter estrogen expression in the brain and have effect on behavior.)

https://www.sciencedirect.com/science/article/pii/S030372079800152X (Show that in adult males, genistein induces estrogenic effects in doses comparable to those in soy-based diets, while in neonatal animals, considerably higher doses are required to show estrogen-like activity.)

https://www.ncbi.nlm.nih.gov/pubmed/12602916 (Shows phytoestrogens were not found to have anti cancer effects.)

https://www.oncologynutrition.org/erfc/healthy-nutrition-now/flaxseed-prostate-cancer-risk/ (Shows that flaxseed oil may make prostate tumors more aggressive.)

https://www.ncbi.nlm.nih.gov/pubmed/14578162 (Shows genistein actually increases growth of mammary tumors that are estrogen dependent.)

http://journals.sagepub.com/doi/abs/10.1177/074823379801400114 (States an increased risk of genital tract tumors in males and a few other possible disorders.)

https://www.jurology.com/article/S0022-5347(05)63824-4/abstract (Shows exposure to genistein during gestation physically demasculinizes the male offspring.)

https://www.tandfonline.com/doi/abs/10.1080/10807039509379993?journalCode=bher20 (Gives evidence for strong correlation of environmental estrogens and rise in breast and male reproductive issues.)