Estrobolome: How Your Gut Microbiome Influences Oestrogen Balance

When we talk about hormone health, we often think about the ovaries, adrenal glands, thyroid, or liver.

But there is another important part of hormone balance that many people do not know about:

your gut microbiome.

Your gut does much more than digest food. It also helps support your immune system, inflammation levels, bowel movements, detoxification, and hormone balance.

One important part of this gut–hormone connection is called the estrobolome.

What is the estrobolome?

The estrobolome is a group of gut bacteria that helps your body process and remove oestrogen.

A simple way to think about it is:

Oestrogen + gut microbiome = estrobolome

Your estrobolome can influence whether used oestrogen leaves your body properly or gets recycled back into your system.

This matters because oestrogen balance can affect:

• PMS

• breast tenderness

• bloating

• heavy periods

• mood changes

• headaches

• fluid retention

• skin breakouts

• perimenopause symptoms

• menopause symptoms

So, if your gut is not working well, your hormone symptoms may feel worse.

Where does oestrogen come from?

Oestrogen is mainly made in the ovaries.

Smaller amounts are also made by the:

• adrenal glands

• body fat tissue

There are three main types of oestrogen:

Oestrone — E1

This is more common after menopause.

Oestradiol — E2

This is the strongest and most active form during the reproductive years.

Oestriol — E3

This is another form of oestrogen, often linked with pregnancy and oestrogen breakdown.

After oestrogen has done its job, your body needs to process it and remove it.

This is where the liver, gut, and bowel movements become very important.

How does your body remove oestrogen?

Your liver helps prepare used oestrogen so it can leave the body.

Think of the liver like a processing centre.

It packages up used oestrogen so it can be removed through:

• the bowel

• urine

Ideally, used oestrogen leaves the body through healthy, regular bowel movements.

But sometimes, gut bacteria can interfere with this process.

What is beta-glucuronidase?

Some gut bacteria produce an enzyme called beta-glucuronidase.

This enzyme can unpack oestrogen that your liver has already prepared for removal.

When this happens, oestrogen may be absorbed back into the bloodstream instead of leaving the body.

In simple language:

Your liver prepares oestrogen to leave the body.

But some gut bacteria can reactivate it.

Then it may go back into circulation.

A small amount of recycling is normal.

But too much may contribute to hormone symptoms.

What happens in the gut?

Once oestrogen reaches the gut, it can go one of two ways.

1. It leaves the body

This is the ideal pathway.

Used oestrogen is removed through stool.

2. It gets recycled

This can happen when beta-glucuronidase activity is too high.

Instead of leaving the body, oestrogen can be reabsorbed back into circulation.

This is why gut health can affect hormone balance.

Why can this be a problem?

If too much oestrogen is recycled back into the body, it may contribute to symptoms such as:

• PMS

• breast tenderness

• bloating

• heavy periods

• mood swings

• fluid retention

• hormonal headaches

• acne

• irritability

• perimenopause symptoms

This does not mean oestrogen is bad.

Oestrogen is important for your body.

It supports:

• bones

• brain health

• skin

• mood

• heart health

• vaginal health

• menstrual cycle health

The goal is not to remove all oestrogen.

The goal is to help your body use it, process it, and clear it properly.

Is beta-glucuronidase bad?

No.

Beta-glucuronidase is not always bad.

Many gut bacteria naturally produce it, and some activity is normal.

The problem is when activity becomes too high or when the gut microbiome is out of balance.

This may happen with:

• low-fibre diets

• constipation

• poor gut diversity

• gut dysbiosis

• high alcohol intake

• high ultra-processed food intake

• chronic stress

• inflammation

• poor liver support

• sluggish bowel movements

When the gut is out of balance, oestrogen clearance may become less efficient.

Which gut bacteria can produce beta-glucuronidase?

Some bacteria that may produce beta-glucuronidase include:

• Bacteroides

• Clostridium

• E. coli

• Eubacterium

• Ruminococcus

• Streptococcus

• Staphylococcus

This does not mean these bacteria are all “bad.”

The gut microbiome is complex.

It is all about balance.

Why bowel movements matter for hormones

Regular bowel movements are very important for hormone clearance.

If you are constipated, used oestrogen can sit in the bowel for longer.

This may give it more time to be reabsorbed.

A simple way to explain it:

Daily bowel movements help remove used hormones from the body.

This is why constipation, bloating, and sluggish digestion can sometimes be connected with hormone symptoms.

Why this matters in perimenopause

During perimenopause, oestrogen and progesterone can fluctuate a lot.

Some months, oestrogen may be high.

Other months, it may drop.

Progesterone often starts to decline as ovulation becomes less regular.

This can lead to symptoms such as:

• irregular periods

• heavier periods

• breast tenderness

• bloating

• anxiety

• mood swings

• sleep problems

• headaches

• hot flushes

• brain fog

• weight changes

If your gut is also not clearing oestrogen well, these symptoms may feel stronger.

This is why gut health can be such an important part of perimenopause support.

Signs your gut–hormone connection may need support

You may benefit from looking at your gut–hormone connection if you experience:

• PMS

• bloating before your period

• breast tenderness

• heavy periods

• irregular cycles

• hormonal headaches

• mood changes before your period

• constipation

• sluggish digestion

• acne around the jawline

• perimenopause symptoms

• digestive symptoms and hormone symptoms together

These symptoms do not always mean “high oestrogen.”

Hormones are complex.

But they can be a sign that your gut, liver, and hormone clearance pathways need support.

How to Support a Healthy Estrobolome

The good news is that there are many simple ways to support your gut and hormone balance.

1. Eat more fibre-rich foods

Fibre helps feed beneficial gut bacteria.

It also helps support regular bowel movements.

Good fibre-rich foods include:

• vegetables

• lentils

• chickpeas

• beans

• berries

• apples

• oats

• flaxseeds

• chia seeds

• nuts

• seeds

• whole grains

More fibre can help your body remove used oestrogen more effectively.

Start slowly if you are sensitive to fibre or prone to bloating.

2. Support daily bowel movements

Healthy elimination is essential for hormone clearance.

To support regular bowel movements:

• drink enough water

• eat enough fibre

• move your body daily

• include magnesium-rich foods

• eat regular meals

• reduce stress

• avoid holding bowel motions

Your bowel is one of the main exit pathways for used hormones

3. Eat cruciferous vegetables

Cruciferous vegetables support liver pathways involved in oestrogen metabolism.

Examples include:

• broccoli

• cauliflower

• cabbage

• Brussels sprouts

• kale

• rocket

• bok choy

These foods can be especially helpful for hormone support.

Cook them if raw vegetables make you bloated.

4. Add more colourful plant foods

Colourful plant foods contain polyphenols.

Polyphenols help feed beneficial gut bacteria and support antioxidant protection.

Include foods such as:

• berries

• pomegranate

• extra virgin olive oil

• green tea

• cacao

• herbs

• spices

• colourful vegetables

The more variety, the better for your microbiome.

5. Reduce ultra-processed foods and excess alcohol

Ultra-processed foods and excess alcohol can affect the gut microbiome, liver function, inflammation, and hormone metabolism.

You do not need to be perfect.

But reducing these can help:

• gut health

• liver health

• energy

• mood

• bloating

• hormone symptoms

Small consistent changes matter.

6. Consider microbiome testing

A microbiome test can give more information about your gut ecosystem.

It may show:

• gut diversity

• beneficial bacteria

• short-chain fatty acid-producing microbes

• beta-glucuronidase activity

• inflammation markers

• gut barrier markers

• pathogens or parasites

• fermentation patterns

Testing can help make your nutrition plan more personalised.

But results should always be interpreted with your symptoms, health history, diet, lifestyle, medications, and blood tests.

Simple Take-Home Message

Your gut plays an important role in hormone balance.

The estrobolome is the part of your gut microbiome that helps regulate oestrogen.

When your gut is balanced, your body can clear used oestrogen more effectively.

When your gut is out of balance, more oestrogen may be recycled back into the body.

This may contribute to symptoms such as PMS, bloating, breast tenderness, heavy periods, headaches, acne, mood changes, and perimenopause symptoms.

Supporting your gut is one of the most important ways to support your hormones.

Final Thoughts

Hormone health is not just about your ovaries.

It is also about your:

• gut

• liver

• bowel movements

• microbiome

• inflammation

• stress

• sleep

• nutrition

A healthy gut can support healthier oestrogen metabolism and better hormone balance.

If you are experiencing PMS, perimenopause symptoms, bloating, heavy periods, breast tenderness, mood changes, or digestive symptoms, your gut–hormone connection may be worth exploring.

Your gut is part of your hormone story.

Personalised Support

Because every microbiome is unique, I highly recommend Microba Microbiome Testing for anyone wanting a deeper understanding of their gut–hormone connection.

Microbiome testing can provide valuable insights into your gut bacteria, microbial diversity, short-chain fatty acid production, gut health markers and other patterns that may influence digestion, inflammation and hormone balance.

For more information, you can visit the Microba website:https://microba.com/patients/

Alternatively, you can contact me or learn more about microbiome testing here:https://www.clinicalnutritionbyola.com.au/microbiome-tests

Your results are best interpreted alongside your symptoms, health history, diet and lifestyle so you receive personalised, evidence-based nutrition recommendations.