Executive Summary
When the blood levels of the female hormone oestrogen are very low, flaxseeds act like oestrogen. This is relevant in menopause and certain hormone-dependent cancer treatments.
Men have low, but not too low, levels of oestrogen; so flaxseeds don’t cause hormonal effects in men when consumed in normal amounts (15 grams a day).
When there is enough oestrogen circulating in the blood, flaxseeds act in an anti-oestrogenic manner. When oestrogen levels are raised by oral contraceptives or hormone replacement therapy, consuming flaxseeds gives the opposite effect.
Flaxseeds are healthy superfoods with anti-inflammatory, anti-diabetes, anticancer and digestive properties and are protective of the heart, brain and bones.
Some of their benefits accrue from plant compounds called lignans. Flaxseeds contain 75 to 800 times more lignans than other plant foods.
Note: Lignans, plant compounds digested in the gut, are different from lignins, indigestible compounds found in wood.
Phyto-oestrogens
In the human body, lignans mimic the female hormone, oestrogen, because they have chemical structures similar to the hormone. They can attach to the body cell receptors that latch onto the oestrogen molecules, triggering oestrogenic actions in the body.
Lignins are called phyto-oestrogens, with ‘phyto’ meaning plant. Besides lignans, there are many other phyto-oestrogens, which we will cover in another article.
Since phyto-oestrogens are similar but not identical to the female hormone, their action is mildly oestrogenic, which causes them to behave in interesting ways.
Are Flaxseeds Oestrogenic or Non-Oestrogenic?
Lignans in flaxseeds display oestrogenic as well as anti-oestrogenic behaviours with the following rules:
- When the blood levels of oestrogen hormone are low, lignans act like oestrogen.
- When there is enough oestrogen circulating in the blood, lignans act in an anti-oestrogenic manner.
Why would that happen? Here is an analogy.
Oestrogen is like a professional while phyto-oestrogens are amateurs at the task.
Consider a house is to be painted. When there are no professionals around, any unskilled person can try his hands at painting and do a passable job. However, if the house is handed over to skilled painters, any interference from an inexperienced person is at best a hindrance. In other words, when professionals are at hand, an amateur is an inept ‘anti-painter’, while in their absence, such a person is a make-shift painter.
Similarly, when there is adequate oestrogen present in the blood, lignin molecules compete for the same cell oestrogen receptors and bring down the average oestrogenic effect. This is effectively an anti-oestrogenic outcome. On the other hand, when there is scarce oestrogen in the blood, lignin molecules cause mild oestrogenic action.
When Flaxseeds’ Hormonal Action Is Risky
In some situations, this behaviour can be dangerous and one should avoid flaxseed consumption.
Hormone-Dependent Cancers
Some cancers of the breast, ovaries and endometrium are triggered or accelerated by body hormones. A few such hormone-dependent cancers need the presence of oestrogen. Their medical treatments focus on preventing the body from producing oestrogen or blocking cell receptors from binding to it.
Flaxseed can raise the oestrogenic action in such patients and should be avoided. Interestingly, the evidence is mixed about it. Many trials have shown the benefit of flaxseed consumption in arresting such tumour growth.
Interestingly, some new evidence suggests that phytoestrogens can protect against these cancers. Of course, this should not be confusing. Such cancers develop in the presence of oestrogen, which is when flaxseeds act anti-oestrogenic and preventative.
My preference is: When in doubt, stay out. When one is suffering from hormone-dependent cancers, it is imprudent to use flaxseeds without absolute proof of their safety.
Solution: Consume flaxseed oil, which has lignins removed and does not have any phytoestrogens, posing no risk in the cases of hormone-sensitive cancers.
Oral Contraceptives and Hormone Replacement Therapy
When taking oral contraceptives or undergoing oestrogen replacement therapy, the aim is to raise blood oestrogen levels. In such cases, consuming flaxseeds reduces oestrogen levels as lignins jostle with oestrogen molecules for the same cell receptors reducing the oestrogen action.
Solution: You should either avoid flaxseeds or wait an hour or two after taking the oral contraceptive or therapy session.
Some information in this article is taken from my book Superfoods, Super Life published by Pan Macmillan India Publishers. The book covers twenty superfoods: Tomatoes, coconut, capsicum, drumsticks, amla, jamun, turmeric, aloe vera, papaya, garlic, ginger, pineapple, carrots, spinach, beets, green tea, cinnamon, flax seeds, asafoetida (hing), and sabja (sweet basil seeds). The book gives their nutrients, health benefits, recommended amounts and excess levels. It explains how to select, prepare and store them and who should avoid them.
Paperback and Kindle versions are available on Amazon India on this link and Amazon USA on this link.
To Read More
- American Institute for Cancer Research: Flaxseed: Full of Fiber and Phytochemicals
- Mayo Clinic: Flaxseed and flaxseed oil
- On this website: Heart-Protective Benefits of Flaxseeds
- Livestrong: Can Flaxseed Increase Estrogen Levels?
- On this website: Is ground flaxseed better than whole flaxseed?
- Research Paper (2017): The potential health effects of dietary phytoestrogens
- Breast Cancer Prevention Partners: Phytoestrogens
- NutritionFacts.org: Beer Phytoestrogens
- Research Paper (2007): Phytoestrogens: food or drug?
- Healthline: Are Phytoestrogens Harmful for Men?
- iCliniq: Estrogens and Phytoestrogens in Male Infertility – An Overview
- Research Paper (2019): Phytoestrogens and Their Health Effect
First Published on: 11th February 2024
Image Credit: azerbaijan_stockers on Freepik
Last Updated on: 14th February 2024