Gut Health

The Gut-Hormone Connection in 2021

Gut diversity and associated hormonal balance play a significant role in human health and well-being...

What happens deep inside your gut often mirrors your overall health condition, from the way you absorb nutrients through to immune system function and hormone regulation.

There are roughly 100 trillion microorganisms living in your gastrointestinal tract, and these microbes help to regulate many aspects of human physiology.

According to exciting new research, gut microbes help to regulate oestrogen levels, which means they have an important role to play before, during, and after menopause. There are many common and unwanted digestive symptoms linked to perimenopause, menopause, and post-menopause, with these symptoms possibly attributed to specific hormonal imbalances in the gut.

Along with a healthy diet and exercise regime, lifestyle changes and herbal extracts are essential in the promotion of digestive system function and hormonal balance.

The gut hormone connection is vast, and we’re going to explore it in detail.

microscopic organisms

What is the Gut Microbiome?

The gut is involved in numerous physiological processes, with approximately 300 to 500 bacteria and other microorganisms responsible for maintaining good human health. Sometimes called the “forgotten organ," the gut is comprised of microorganisms which communicate with the host’s immune system through a variety of mutually beneficial metabolic processes.

Unhealthy gut microbiota has been associated with a range of human diseases, including allergic diseases, neurodevelopmental illnesses, metabolic diseases, and digestive symptoms related to hormonal imbalances.

The number of bacteria within the gut is 10 times more than all the cells in the human body. This microbiome weighs more than the human brain and has a collective bacterial genome vastly greater than the human genome. Growing awareness of gut health highlights a significant shift in how we understand human health and our symbiotic relationship with the surrounding environment.

What is the Estrobolome?

Oestrogen is one of only two primary female sex hormone groups, along with progesterone. Oestrogen is responsible for a wide range of reproductive system and physical characteristics, helping to develop and maintain the reproductive system and female body. The estrobolome is a collection of bacteria in the gut capable of metabolising and modulating oestrogen. Because the estrobolome directly affects oestrogen levels, it has a huge impact on weight and mood.

Oestrogens are the individual hormones that make up the oestrogen group. The estrobolome helps control how these hormones circulate in the body, from the liver to the bile to the small intestine.

In the estrobolome inside your gut, these microbes produce an enzyme known as beta-glucuronidase. (1) This enzyme disrupts inactive oestrogens and pushes them to switch to their active form. Activity from beta-glucuronidase produces unbound and active oestrogen, which binds to oestrogen receptors and encourages a range of critical physiological processes. (2)

Understanding Oestrogen Metabolism

The estrobolome is vital to female hormonal regulation through the process of oestrogen metabolism. Your ovaries are the primary organs responsible for making oestrogen, which then circulates throughout your body to your breasts, uterus, and other organs.

Once it reaches your liver, it's inactivated before being sent to your intestines. It stays inactive until it passes through your intestines and exits your body in your stool. This entire process is defined as healthy oestrogen metabolism.

How Does the Estrobolome Impact Oestrogen Metabolism?

When you have a healthy gut microbiome, your estrobolome will produce the correct amount of beta-glucuronidase to keep your oestrogen levels balanced. However, when you have gut dysbiosis, defined as microbial imbalance or maladaptation, it can alter the activity of the beta-glucuronidase in your system.

In turn, you end up with an excess or deficiency of free oestrogen in your body. This can promote the development of numerous oestrogen-related pathologies (3) and influence many digestive symptoms linked to perimenopause and menopause.

For example, having too much beta-glucuronidase in your system can boost your oestrogen levels above a healthy threshold. If you have too little beta-glucuronidase in your system, it can lower your oestrogen levels. Having too much of this enzyme has links to harmful bacteria overgrowth, and not having enough of this enzyme is linked to lower levels of good bacteria. 

woman fanning herself to cool down

Female Life Stages and Links To Estrobolome Dysfunction

The gut microbiome plays an important role in the regulation of oestrogen levels. When these levels are excessive or deficient, they can influence the risk of developing numerous oestrogen-related diseases. The following life periods have known links to estrobolome dysfunction and associated hormonal imbalance.


Perimenopause typically refers to the time just before menopause when the body makes the natural transition to menopause. This transition marks the end of the reproductive years and is linked with declining oestrogen levels. While a decline in oestrogen is normal during this period, sometimes there can be more oestrogen present.

Oestrogen levels can cause issues when they change quickly or in an irregular fashion, with existing estrobolome dysfunction possibly causing digestive symptoms and other problems.

Incorrect beta-glucuronidase levels in your gut microbiome during perimenopause can increase the likelihood of bloating, gas, stomach pain, pressure, digestive tract inflammation, and fluid retention, among other symptoms.

In addition, declining oestrogen levels have been shown to create issues with cortisol regulation, with this "fight or flight" hormone triggered by everyday stress and known to influence existing mental health conditions such as anxiety and depression. (4)


Menopause starts 12 months after the last menstruation. While "the change of life" can be positive in many ways, it is also associated with a range of hormonal imbalances and digestive issues. Researchers have discovered connections between female sex hormone levels and gut composition in menopausal women, with oral, vaginal, and gut microbiota composition known to be regulated by oestrogen levels. (5)

While questions remain unanswered about the role of microbiota during specific menopause stages, the gut-hormone connection is well-established and known to influence multiple biological functions. An unbalanced microbiome during menopause can cause either oestrogen deficiency or excess.


During post-menopause, estrobolome disruptions may have links to various health conditions like obesity and cardiovascular issues. Oestrogen plays a critical role because it works to regulate adipocyte differentiation, glucose, lipid metabolism, and the wider inflammatory response.

When you go through menopause, your natural levels of oestrogen start to drop. In turn, it can disrupt these oestrogen-dependent processes and trigger cardiovascular disease and obesity. (6)(7)

Gut dysbiosis can lead to decreased beta-glucuronidase activity, and may also increase the risk of developing numerous chronic diseases. An unbalanced gut can make conditions worse for post-menopausal women who are already suffering from low oestrogen. Research highlights important relationships between oestrogen deficiency, the estrobolome, and disease occurrences. (8)(9)

Other Conditions Linked to Estrobolome Dysfunction

Along with affecting specific periods of life, excessive or deficient oestrogen and beta-glucuronidase levels have been linked to specific diseases and physiological conditions.

1. Too much beta-glucuronidase

Beta-glucuronidase is an enzyme that causes inactive oestrogen to go active. Active and unbound oestrogen can bind to oestrogen receptors, which can encourage the growth of “bad” bacteria in your gut. In turn, having too much “bad” bacteria in your gut can lead to a variety of oestrogen-related conditions. (10)

Oestrogen dominance

Oestrogen dominance happens when there is too much oestrogen in the body without having adequate levels of progesterone to lower it. Progesterone is a steroid hormone that helps to ensure oestrogen balance. (11) Too much beta-glucuronidase causes free oestrogen levels to go up by activating inactive oestrogen molecules.

It also encourages bacteria growth in your gut, and this can cause inflammation. Inflammation can lead to further issues related to bacteria and intestinal permeability. (12)


Endometriosis is a medical condition wherein endometrial tissue grows outside of the uterus. This condition is driven by oestrogen and has been associated with gut dysbiosis. In animal studies, those with endometriosis have been shown to have a larger number of bacteria and beta-glucuronidase, and in turn, higher oestrogen levels. (13)Dysbiosis of the endometrium and vagina were also common, leading to a decrease in Lactobacilli bacteria. Endometriosis can also result in increased pathogenic gram-negative bacteria. (14)

2. Too little beta-glucuronidase

On the other end of the spectrum, having too little beta-glucuronidase in your system can also lead to estrobolome dysfunction. The following conditions are associated with this imbalance:


Polycystic ovary syndrome (PCOS) is another condition with strong links to estrobolome disruption. Women with PCOS have higher androgen levels compared to oestrogen, as well as altered levels of gut bacteria. Research supports the theory that gut bacteria alteration in women with PCOS can encourage higher androgen levels and decreased oestrogen levels because it reduces beta-glucuronidase activity. (15)(16)

Researchers found that taking gut bacteria and modulating it with faecal microbiota transplantation (FMT) could decrease androgen biosynthesis and improve the oestrous cycles in animal models. This shows that modulating your estrobolome could be useful when it comes to treating PCOS. (17)

person holding their knee


Osteoporosis is a condition where your bones weaken with age and become more prone to fracturing and breaking. This condition becomes even more relevant due to the normal hormonal changes that happen as you age. Once you go past menopause, your oestrogen levels drop, which can cause issues with your levels of beta-glucuronidase. (18)

Research and studies show that gut microbiota has direct links to hormone levels and fluctuations. In turn, this may contribute to osteoporosis. Studies involving mice showed that introducing Lactobacillus rhamnosus into their diet could boost their levels of beta-glucuronidase. When this happened, it helped to improve oestrogen levels, and this protected against bone loss due to osteoporosis. (19)(20)

Common digestive symptoms linked to menopause

Perimenopause, menopause, and post-menopause have been linked to numerous digestive symptoms, many of which can be attributed to hormonal imbalances. Common symptoms include bloating, gas, stomach pain, pressure, digestive tract inflammation, and fluid retention, among others. These symptoms can arise during any stage of the menopause cycle and are often linked to imbalanced levels of beta-glucuronidase.

We already know that hormonal health and gut health are intimately connected. During menopause, wildly fluctuating oestrogen and progesterone levels are known to create digestive issues due to incorrect oestrogen detoxification and excretion. When oestrogen isn’t removed from the body properly, it can be reabsorbed in the bowel and go back into blood circulation.

During the first step of elimination, oestrogen is taken into the liver and broken down into metabolites. It is then combined with other compounds and delivered to the intestine through the bile. In the final stage, oestrogen is deposited into the large intestine, which is when your gut bacteria get to work. When there is too much beta-glucuronidase involved, oestrogen is unpackaged and reabsorbed by the body.

This is known to cause the following digestive symptoms, some of which can persist for a long time and lead to additional physiological issues:

  • Bloating
  • Stomach issues, gas, and burping
  • Acid reflux or heartburn
  • Food intolerances
  • Reduced alcohol or spicy food tolerance
  • Diarrhoea or constipation

How to Improve Gut Health and Reduce Digestive Symptoms

Fortunately, there are several things you can do to improve the estrobolome balance in your body and deal with specific digestive issues and other challenges. The following are relatively easy to incorporate into your daily routine, and anyone can benefit from the results:

a variety of healthy fat rich foods
1. Eat healthy food

Eating natural and unprocessed foods is an excellent way to promote a healthy gut microbiome. Consider including cruciferous vegetables and antioxidant-rich foods like blueberries, flaxseed oil, and ginger in your diet. A high-fibre intake can help to restore healthy gut flora. Healthy fats, fermented foods, and seasonal fresh fruits and vegetables are also known to improve gut health.

One of the easiest things you can do to improve your estrobolome balance is to add more vegetables to your meals. Veggies are generally high in fibre and help to promote a healthy microbiome by decreasing beta-glucuronidase activity.

In particular, broccoli sprouts are helpful because they can detox excessive oestrogen out of your body. The sulforaphane content in broccoli helps to activate your body’s liver detox system and flush out excess oestrogen. (21)(22)       

Veggies also help to improve your microbial diversity by introducing probiotics and feeding good bacteria. One study took 53 healthy volunteers and split them into five random groups. They collected faecal samples before and after the trial to measure the amount of bacteria present. Each group got different strains of probiotics. At the end of the study, researchers found that the volunteers who consumed lactulose or oligofructose-enriched insulin had lower beta-glucuronidase activity. (23)

2. Exercise and weight management

Our gut helps regulate our hormone levels through a feedback process based on what we eat and how we move. While food provides the necessary fuel, exercise lets us use this fuel more efficiently. When combined with a healthy diet, exercise helps to promote better hormone regulation and metabolism. There are several benefits associated with physical activity, including lower stress levels, healthy weight loss, and reduced chronic disease risks. (24)(25)

Research has linked fitness levels with the uptake of bacteria, including a short-chain fatty acid call butyrate. A study involving professional rugby players highlighted more diverse gut flora than the general population. They had twice the amount of bacterial families compared to the trial’s control groups. (26)(27)

A second study compared the gut flora of 21 non-active women and 19 active women. Researchers found that the active women had higher levels of bacteria that promote good health like Bifidobacteria and Akkermansia. These findings suggest that engaging in physical activity regularly can benefit your gut flora. (28)

woman drinking wine

3. Reduce your alcohol intake

Increased alcohol consumption can adversely affect beneficial gut bacteria, influence hormonal balance, and create digestion problems. One study examined gut bacteria in 41 people with a chronic alcohol condition and then compared the bacteria levels with 10 healthy people with no or minimal alcohol intake.

While dysbiosis was found in 27% of the alcoholic group, none of the healthy individuals had it. (29) So, while red wine consumption — in moderation — can be beneficial due to the polyphenol content, (30) excessive alcohol consumption should always be avoided.

4. Manage antibiotics and medications

Antibiotics are an important treatment option for various diseases and infections. However, antibiotics have an impact on both good and bad bacteria. (31)(32) While they are undeniably useful at times, antibiotics can wreak havoc on the health of your gut.

Antibiotics usually make good bacteria like Bifidobacteria and Lactobacilli decline and increase bad bacteria such as Clostridium. One study showed that taking even one round of antibiotics can alter your gut bacteria for an extended period. (33)(34)

Common medications like paracetamol and antacids can also interfere with beneficial microbes in your gut, so try to limit your consumption of these medications where possible. Additionally, oral contraceptives can throw off your estrobolome balance due to the synthetic nature of these hormones.

This can easily lead to an overload of oestrogen in your body, which can impact your gut bacteria. A review involving 12 studies showed that taking oral contraceptives could quadruple the oestrogen levels present in the body. (35)

5. Stop smoking

Tobacco smoke includes thousands of chemicals, many of which are known to cause cancer. Routine smoking can harm almost every organ in your body and increases your risk of developing stroke, heart disease, and lung cancer, among other conditions. 

Both tobacco smoke and associated conditions linked to smoking can cause long-term health problems that negatively impact your gut flora. (36)(37) One study monitored the bacteria levels of smokers with people who had stopped smoking. The people who quit smoking had increased gut flora diversity compared to the people who didn’t quit. (38)

6. Take probiotics

Probiotics can help to balance your estrobolome by restoring beneficial bacteria and increasing gut diversity. Studies involving animals with PCOS showed the benefits of a supplement containing a broad-spectrum Lactobacillus probiotic. This supplement helped to decrease testosterone biosynthesis and normalise hormonal cycles. 

(39) In one study, mice were given a supplement containing Lactobacillus reuteri, which was able to help protect against osteoporosis and bone loss due to low oestrogen levels. (40) 

bottle with an eye dropper


7. Benefit from powerful herbal extracts

Many potent herbal extracts are capable of promoting gut health when combined with a healthy diet and exercise regime. These extracts are especially beneficial for women experiencing digestive symptoms and other issues as a result of life changes.

From perimenopause to menopause and post-menopause, many of the complaints associated with oestrogen and beta-glucuronidase imbalances can be treated with traditional herbal remedies.

The following two extracts are especially beneficial:

Chamomile Extract

Chamomile has been consumed for centuries as a natural remedy for a range of health conditions. It is loaded with antioxidants and may play a role in lowering the risk of heart disease.

Chamomile also contains apigenin, an antioxidant that binds to certain receptors in the brain that induce sleepiness and alleviate insomnia. (41) Additionally, chamomile has properties that may aid with digestion, including digestive tract inflammation, premenstrual tension, and stomach pain.

Some studies with mice have shown how chamomile extract may reduce the risk of certain gastrointestinal conditions, including the potential to protect against diarrhoea in mice and inhibit the growth of bacteria contributing to ulcer development.

(42) Chamomile has traditionally been taken to treat digestive ailments such as stomach discomfort, nausea, and gas, and is taken readily to help manage menstrual and menopausal symptoms around the world.

fennel seed

Fennel Seed Extract

Fennel seed is a culinary and medicinal herb with numerous antioxidant, anti-inflammatory, and antibacterial health effects. This flavoursome herb is extremely low in calories and has a diverse and highly nutritious vitamin and nutrient profile.

Fennel seed contains a number of powerful antioxidants and potent plant compounds, some of which may be beneficial for digestive health and overall gut balance. This powerful herb is a great aid for your digestive tract, as it helps to soothe muscles, reduce gas and bloating, and prevent stomach cramps.

A review of 10 studies into fennel seed extract noted a range of positive effects for people during the menopause period. (43) Aside from improving sexual function and satisfaction in menopausal women, fennel seed was also able to help relieve hot flashes, minimise vaginal itching and dryness, decrease pain during sex, and lessen sleep disturbances.

Fennel seed continues to show promise as a digestive aid and is often taken to relieve digestive bloating, flatulence, and menstrual pain. 

Moving forward with a healthy gut and balanced hormones

Looking after the health of your gut microbiome is vital to ensure hormonal balance and positive health outcomes at any stage of life. Estrobolome imbalances are a particularly significant issue for women during perimenopause, menopause, and post-menopause.

Digestive problems are common during this time, as fluctuating hormone levels and estrobolome dysfunction can cause additional pressure to everyday life.

Eating healthy and engaging in regular physical activity are excellent ways to look after your gut and improve your general health during any significant life change.

Additional proactive measures may help you to manage your hormone levels and look after your estrobolome during this difficult time. Making healthy lifestyle changes is equally important, as well as the introduction of powerful natural plant allies like chamomile extract and fennel seed extract.

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