What are phytoestrogens and how do they affect hormones during menopause?

Phytoestrogens in food aren’t really new, but they seem to be getting a lot more attention these days. Although we’ve been eating phytoestrogen foods for a very, very long time, it wasn’t until the 1920s that phytoestrogens were discovered and they became a ‘thing’.

So if we break this word, phytoestrogen down into its components, ‘phyto’ means plant, and ‘estrogen’ we know as a hormone. So the literal meaning of the word phytoestrogen is ‘plant hormone’. 

Seems pretty simple, huh? Or is it?

Plant-based nutrients

Our foods contain many varied bioactive compounds or little bits of natural chemicals that serve a purpose for the plant and then can have nutritional benefits when consumed. 

Plant-based foods are loaded with bioactive compounds, and, as you probably guessed, phytoestrogens are in this category.

When phytoestrogens were first discovered, it was noted that they were very similar in structure to the oestrogen found in animals. 

Phytoestrogens belong to a larger group of natural phenolics, including isoflavones (found in many types of beans, including soybeans), coumestans (also found in beans, plus red clover and alfalfa) and prenyl flavonoids (found in hops).

What does this tell us?

Well, it tells us that phytoestrogens are found in many different plants, but especially in beans and certain medicinal herbs.

What do phytoestrogens do?

Now, this is where I think much of the confusion comes into play.

On the one hand, we have phytoestrogens, or plant hormones, that are very similar in structure to our human oestrogens,

And then on the other hand phytoestrogen-rich foods are often used to reduce oestrogen levels.


While the structure of most phytoestrogens in foods is very similar to animal oestrogen, the effect on the body is mostly associated with the interaction that the phytoestrogen has with oestrogen receptors.

This is where the understanding of the MOA or the mode of action of phytoestrogens is important.

Phytoestrogens can work as agonists or antagonists for oestrogen, they can help to modulate oestrogen levels, not just increase oestrogen.

How do phytoestrogens modulate oestrogen?

Let’s start with oestrogen receptors. These are proteins, within the cell that are activated by the hormone oestrogen.

Phytoestrogens can interact with these oestrogen receptors and, they can help to ‘top up’ oestrogen by binding to receptors when oestrogen levels are low. Kind of tricking our body into believing there is more oestrogen than there really is.

Ok, but what about when oestrogen levels are high?

So here’s the tricky thing – the critical aspect of oestrogen modulation by phytoestrogens is their additional activity with SHBG or sex hormone-binding globulin. SHBG is a protein that attaches to oestrogen, it works to control the amounts of certain types of hormones in your body.

Phytoestrogens can bind to and inactivate SHBG, therefore controlling the bioavailability of oestrogen.

To summarise:

This means that if your oestrogen levels are low, then phytoestrogens can bind to oestrogen receptors to help your body to replenish low oestrogen stores.

Or, if your oestrogen levels are high, phytoestrogens can bind to sex hormone-binding globulin (SHBG) to limit the availability of oestrogen.

This, of course, makes phytoestrogens an essential part of your meals, not just when you are transitioning through menopause, but before and, especially after menopause.

So, what is the real benefit of including phytoestrogens with your meals?

As you probably guess, phytoestrogens can help to balance your hormones, and this means, when you’re including these nutrients in your daily diet, just in small amounts, you are investing in your hormone health and overall well-being.

In the short-term, phytoestrogens can be considered as your own ‘natural HRT’ providing your body with modulating nutrients for oestrogen levels in your body. During perimenopause this can correlate with reduced frequency and intensity of sensations such as hot flushes, anxiety or night sweats.

The long-term health benefits of phytoestrogens include possible prevention of osteoporosis, cardiovascular health and dementia. These are the three main health concerns that present themselves once oestrogen levels decline after menopause.

Including phytoestrogens in your meals

Of course, time is of the essence, and I encourage you to include phytoestrogen foods in your meals right through perimenopause. These little changes, such as including flaxseeds, sprouts and beans into your meals can make quite a difference to your hormones and how you feel.

My favourite phytoestrogen foods are fenugreek, flaxseeds, mungbean sprouts, quinoa and of course, GM-free fermented soy products such as tempeh and miso.

There are several other plant-based foods that are rich in phytoestrogens, let me know what your favourite sources of phytoestrogens are.

Please note, if you have a history of oestrogen-dependent cancer or are experiencing other issues with hormones, I suggest that you seek guidance from your healthcare provider before you go too gung ho with phytoestrogens in your foods.

The information provided in this article is for information purposes only and should not be taken as medical advice. We recommend you consult with a GP or other healthcare professional before taking action based on this article. While the author uses their best endeavours to provide accurate and true content, the author makes no guarantees or promises regarding the accuracy, reliability or completeness of the information presented. If you rely on any information provided in this article, you do so at your own risk.

About The Author

Leonie Satori

Naturopath and Herbalist Leonie is passionate about women’s health, especially perimenopause and all that midlife encompasses for women - anxiety, gut health and hormones. Her holistic and down-to-earth approach to well-being incorporates wisdom from traditional healing practices, including Western herbal medicine and Ayurveda plus over a decade of clinical experience. In her free time, you’ll find Leonie bush-walking, gardening and living life slowly.

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