The Estrobolome: The Fascinating Way Your Gut Impacts Your Estrogen Levels

At some point in your life, it's likely that you’ve noticed a connection between your digestive system and your hormones, probably in the form of annoying or uncomfortable premenstrual bloating, or the loose stools so many women experience like clockwork just before their period starts. But have you ever considered that acne, period pain, PMS, PCOS, endometriosis, or fibroids could be related to not just your hormones, but something going on in your gut? 

We tend to think of our reproductive and digestive systems as being entirely separate and unrelated. After all, we go to completely different doctors when there’s trouble in one or the other, right? It's exactly how medicine works – seeing the body as separate compartments, rather than as one whole organism. But what we've learned about gut health in the past decade shows us that we need to rethink this limited view of health and physiology. The far-reaching effect of the microbiome on our total health is nothing short of astonishing: there's very little that isn't impacted by your microbiome.

We're going to focus on the important role of your microbiome on your hormone balance – particularly when it comes to estrogen.

Estrogen 101

Before we jump into the gut-estrogen connection, I thought it might help to have a little primer on estrogen. What is it, really?

Estrogen is actually a collection of three chemically similar molecules that play a major role in the development and function of the female reproductive system from puberty through menopause, and beyond, as well as in the health of our bones, memory, moods, and cognitive function, heart and cholesterol levels, and so much more.

There are 3 primary forms of estrogen:

Estrone (E1): Estrone is primarily manufactured in the ovaries prior to menopause, and can also be manufactured in our adipose tissue and adrenal glands. While our total level of circulating estrogen declines after menopause, we do continue to produce estrogen, mainly in the form of estrone.

Estradiol (E2): Estradiol is the major form of estrogen produced in the ovaries in premenopausal women, though some it is also manufactured by the adrenals and during pregnancy by the placenta. It is the most abundant one we produce during our reproductive years, and the most active and potent. It plays a role in breast development, the characteristic distribution of fat in females, is important for maintaining reproductive tissue health, and also supports bone growth, and heart health, memory and cognitive function. It's also the form of estrogen that plays a role in conditions including endometriosis, uterine fibroids, breast and endometrial cancers, as well as in cyclic menstrual cycle symptoms.

Estriol (E3): This is the least potent form of estrogen, and is predominant in pregnancy, as it is produced in large quantities by the placenta.

While estrogen levels are constantly fluctuating, daily and throughout our life cycles, there are a couple of common denominators of estrogen imbalance and how they can show up in our hormonal and gynecologic health:

High estrogen levels: Excess estrogen can cause irregular periods, mood swings, weight struggles, headaches, acne, bloating, and other digestive symptoms. And when estrogen levels remain too high for too long, this can play a role in conditions like endometriosis, fibroids, and reproductive cancers.  

Low estrogen levels: When estrogen is too low, it can lead to problems with sleep, mood, vaginal dryness, urinary tract irritation, low libido, loss of bone density, and worsened perimenopausal symptoms, for example.

One thing we’ve learned about the gut microbiome over the last decade is that the gut microbiome shares a particularly close relationship with estrogen.

What’s Your Gut Got to Do With It? Meet Your Estrobolome

Remember the story of Goldilocks and the Three Bears? Goldilocks tried each porridge until she found the one that was “just right.” You can think of your body’s estrogen balance in a similar way; you want just the right amount – not too much and not too little – or problems start to arise.

Your body is genius – I mean really brilliant. You have an entire microbiome department solely dedicated to the task of regulating your estrogen levels. It’s called the estrobolome, and it's a unique microbiome within your gut microbiome, made up of a collection of bacteria with special genes that help you metabolize estrogen. The estrobolome is central to keeping your estrogen levels, which are ever dynamic throughout your monthly menstrual cycles – and life cycles – juuuuust right.  

Here’s an overview of how it works: 

You Gain Some, You Lose Some

Throughout our menstrual cycles, during pregnancy, and all the way into menopause, we produce estrogen day in and day out. After estrogen circulates throughout your body – doing “all the things” it needs to do, from keeping your hair shiny and your menstrual cycles healthy to keeping your bones strong – it winds up in the liver where it’s broken down into estrogen metabolites and packaged for elimination or reabsorption, then delivered to its final destination for just that: your intestines. 

Once in your intestines, estrogen is either eliminated or reabsorbed and recirculated throughout the body, ideally creating that “just right” balance that your body thrives on. Amazingly, this entire operation is guided by your estrobolome bacteria. They do this by producing an enzyme known as beta-glucuronidase, which breaks down estrogen into its active forms, and they're either excreted or reabsorbed into your circulation to do their work in your body.

A Factory Making Estrogen from Plants

As if the magic never ends – you can make estrogen from certain plant-based foods, especially leafy greens, legumes (i.e., lentils, garbanzos, tofu), and some seeds – like flax seeds. All of these contain compounds called phytoestrogens, naturally-occurring plant compounds that are structurally or functionally similar to our own estrogens. Through a complex process, a healthy estrobolome is able to take these phytoestrogens and transform them into compounds that have estrogen-like compounds that our body can then use as well. 

Now you may be thinking: Wait, isn’t too much estrogen a problem? Yes, it’s true that we try to avoid the potentially harmful xenoestrogens found in our cleaning products, beauty products, and cosmetics. Those can harmfully increase our estrogen levels and wreak hormonal havoc. But phytoestrogens may actually play a protective role in our overall hormonal health. When estrogen levels are high, they can block the estrogen receptors, protecting you from the risks of excess estrogen exposure; when estrogen is low, they can provide enough to keep your estrogen levels supported. 

When these two systems of estrogen metabolism are working the way they’re supposed to, you absorb and excrete the right balance of estrogen, creating happy, healthy hormone balance along the way. And here’s a win-win: healthy estrogen levels in turn support healthy gut function. Estrogen helps maintain the health and integrity of your gut lining, preventing leaky gut. So it’s a win-win. 

But here’s the thing: your estrobolome can only function properly if your microbiome is healthy and contains the right type and diversity of microorganisms. And when the estrobolome doesn’t, which is an all-too-common problem – about 90% of women report experiencing disruptive digestive symptoms – it can throw off not just your digestion but also the delicate balance of estrogen in your body. 

There’s a continuous conversation taking place between your GI tract and your endocrine system – one you probably never suspected, and perhaps only hear the whispers of in the form of symptoms that show up when there’s a communication breakdown. That communication breakdown can happen in the form of common and troubling to significant hormone imbalances and gynecologic conditions including: 

Premenstrual Symptoms: Fluctuations in estrogen levels create the rhythm of menstrual cycles as you flow through each phase. But when your gut can’t regulate properly, imbalanced estrogen levels can contribute to bloating, menstrual migraines, heavy periods, and with it, increased period pain.

Endometriosis: Research shows that a disrupted microbiome is crucially involved in the onset and progression of endometriosis. Women with endometriosis have higher amounts of dysbiosis overall as well as bacterial overgrowth in the estrobolome, leading to higher estrogen levels that stimulate endometrial growth. Women with endometriosis also have much higher rates of IBS, suggesting an important connection between endometriosis and a disrupted microbiome.

PCOS: Studies have shown that women with PCOS have significantly lower microbial diversity. Further, dysbiosis in women may contribute to both insulin resistance and increased testosterone production – two of the main hormonal shifts in PCOS that drives symptoms like hair loss, acne, and hair growth in unwanted areas. 

Cyclic Breast Pain: High estrogen can lead to cyclic breast pain. Recent research has also found that your gut microbiome affects the microbiome at your breast tissue – an amazing example of the interconnection of what seem like separate areas of our bodies. 

And more….Because of estrogen’s various roles in the body, combined with the gut’s influence over all of our systems, research has shown that estrobolome disruption also impacts cardiovascular disease, metabolic syndrome, cognitive function including a decline in memory, and estrogen-related cancers including endometrial, cervical, ovarian, and breast cancer.

Trouble in Paradise

A healthy microbiome is made up of a very wide variety of organisms, in the right amounts, and located in the right places. It should be like the Amazon rainforest, lush and full of different species that work together to create a vibrant and energetic ecosystem. If you're already somewhat gut health savvy, or you're a frequent visitor to my blog or social media page, you’ve probably heard of dysbiosis – a problem that arises when gut microbes get knocked out of balance. 

This can show up in a couple of ways, and most commonly as a combination of both: 

Bacterial Overgrowth 

Bacterial overgrowth is when certain bacterial species that you don’t want present in high levels get the upper hand and start to over-proliferate. When this occurs in your estrobolome, too much beta-glucuronidase activity can elevate circulating estrogen levels excessively, and can lead to all sorts of problems in your endocrine system including heavy periods, painful cramps, PCOS, fertility challenges, chronic and recurrent vaginal infections, mood swings, monthly breast pain, and more. Too much estrogen can also lead to conditions like endometriosis, uterine fibroids, and even breast and endometrial cancers.  

Low Microbial Diversity

On the flip side, low microbial diversity is also a common problem. When there aren’t enough of the right types of microbes in your gut to metabolize estrogens, you may experience lower beta-glucuronidase activity. The consequences of this are two-fold: first, your estrobolome isn’t able to adequately convert estrogen to its active form and second, you can’t convert and use those protective plant-based estrogens as well. This leads to an overall low estrogen state in the body; less estrogen is produced and available to enter the bloodstream and go on to perform its important roles in the body.

What Causes Dysbiosis?

Microbiome disruption is a common fact of modern living. Topping the long list of reasons why our gut microbiome can become imbalanced and negatively affect the estrobolome are: 

• a diet low in fiber, good quality fats, and fruits and vegetables, and high in sugar and processed foods
• chronic stress
• the overuse of antibiotics and other medications
• inadequate sleep and circadian rhythm disruption
• a sedentary lifestyle

Our modern lifestyles have stripped away key elements that nourish a healthy microbiome – like eating a fiber-rich diet and getting enough exposure to healthy bacteria found in nature and in fermented foods – creating the perfect storm for dysbiosis. It’s not necessarily just one big trigger that catapults things from healthy to unhealthy; more often it’s persistent, chronic exposure to seemingly small things that start to pile up. The good news is that while studies show that it only takes a few days of eating junk food to muck up your microbiome, conversely, studies also show that with the right foods, and simple lifestyle shifts, we can restore or promote microbiome health in the relatively short span of just a couple of weeks! 

Restoring a Healthy Gut-Hormone Connection

Healing your microbiome – and with it your estrobolome – is not only a key to hormonal health, but we know that a healthy gut also leads to lowered stress levels, improved stress tolerance, and less depression, anxiety, and inflammation. It’s good for our overall health. 

In my new book, Hormone Intelligence, I provide you with a complete protocol for healing your gut – and with it your microbiome.  But you can get started today with the first steps to restoring microbiome health. More than any form of testing, the best gauge that things are moving in the right direction is an improvement in your symptoms. 

Here are the steps you can take to get started: 

Remove Triggers of Bacterial Overgrowth

I’m not into overly restricted diets; in fact, I strongly advise against them, especially when it comes to hormone and gut health, which suffer when diets are too strict. But when it comes to the food groups I mention below, there’s a time and place for their removal. It’s not about taking away the things you love; it’s about allowing your body the space it needs to heal without triggers getting in the way, and making room for the foods that support your body and truly make you feel good.

• Sugar: Diets high in sugar alter the microbiome by favoring the growth of unwanted species of bacteria that contribute to chronic inflammation, weight struggles, and further gut dysfunction with problems like leaky gut. And when you’re filling up on sugar, you’re also missing the nutrients that good flora thrive on.
• Alcohol: Research shows that alcohol can raise estrogen levels in the short and long-term, and one of the ways it’s thought to do this is by negatively impacting the estrobolome. It doesn’t mean that you have to kiss it goodbye forever, but it’s a good reason to let it go for now.
• Ultra Processed foods: Eating a diet of highly processed foods for just 3 days has been shown to have a detrimental impact on gut health, and eating this way for 10 to 14 days can reduce your microbiome diversity by 40%, which means an estrobolome that’s in deep trouble. 
• Environmental pollutants: Pesticides, herbicides, and a number of environmental chemicals are a double whammy; they can negatively shift the microbiome and they also act directly as endocrine disruptors. To support a healthy microbiome, reduce your overall exposure to environmental pollutants by choosing organic when you can and avoiding other endocrine disruptors, which you can learn about here. 

Feed Your Flora with Plant Diversity

Here’s the step I love: adding beneficial foods to create a robust, vibrant diet that literally feeds you and the estrogen-metabolizing organisms in our gut – and are part of a delicious healthful way of eating. 

• Eat a wide variety of plant foods: Your body needs a wide diversity of plant foods to truly thrive. Eating a wide variety ensures that you’re getting both a wide variety of nutrients and phytochemicals, and also the variety of fibers, nutrients, and starches a healthy gut microbiome depends on.  
• Up your plant-based fiber: The best food on the planet for supporting microbiome health is fiber from plant sources, particularly leafy greens in the Brassicacea family like broccoli, cabbages, kale, Brussels’s sprouts, cauliflower, and collards – all a source of phytoestrogens as well. They also have the added bonus of helping to keep estrogen levels healthy by supporting detoxification and the elimination of harmful environmental estrogens as well.  
• Support the production of phytoestrogens by eating lignan rich foods: Lignans are the special type of fiber that estrobolome bacteria convert to phytoestrogens. In addition to leafy greens as above, lentils, chickpeas, whole soy foods like tofu and tempeh, and flax seeds especially are amazing sources.

Re-Seed Your Gut

Pre- and probiotic rich foods are often not a priority on our modern plates. But fermented foods like yogurt, kefir, sauerkraut, and kimchi are a traditional part of almost every culture on the planet, and their importance for the health of your microbiome can’t be overstated. Like a probiotic supplement, but even more powerful, these foods provide beneficial species of bacteria to repopulate your estrobolome. Prebiotics are important because they contain a special forms of starch, fructo-oligosaccharides and inulin, that beneficial bacteria thrive on and in turn produce important nutrients including short-chain fatty acids like butyrate, acetate, and propionate that support intestinal health. Prebiotic foods include artichokes, garlic, leeks, onion, asparagus, beetroot, green peas, grapefruit, and legumes.

I don’t always recommend adding a probiotic, especially if you’re eating plenty of the probiotic-rich foods above, but when dealing with any form of dysbiosis, adding a probiotic with the right species can be an extra layer that helps restore the normal balance of flora in your gut. Choose a probiotic that contains at least 10 billion CFUs of a variety of Lactobacillus and Bifidobacterium. I recommend taking them daily for a couple of months, then back down to a few days each week if you feel you’re continuing to find them helpful. 

Live a Lifestyle Supportive of Microbial Diversity

Any activity that brings you into contact with soil, plant life, and pets or animals that spend time outdoors, increases your opportunity for exposure to microbial diversity:

• If you have kids or a pet, play outside with them – and don’t be afraid to get dirty. I don’t just want you to embrace your kids getting messy, I want you to take after them!
• Work in your garden or take care of your yard if you have one. Even creating a simple herb garden can expose you to more beneficial bacteria. 
• Ideally, purchase organic foods through a CSA or at your local Farmer’s Markets where they’re fresh from the soil. And yes, wash them, but no need to go overboard!
• Get more exercise – adequate daily movement is an important part of microbiome health – as well as healthy daily elimination. It also plays an important role in overall hormone balance.

The gut-hormone connection is powerful and influences our life in more ways than we ever previously imagined. It’s yet another reason that ‘whole woman medicine’ is so important compared to the type of silo’d healthcare most physicians are taught to practice. Even in the wellness, integrative, and functional medicine worlds we so often see articles about “hormone health” and articles about “gut health” – but not many about the connection between them. While it may not be the first thing we think about when struggling with hormonal challenges, improving the health of your gut microbiome can be an important part of your journey towards hormone health. I hope the strategies here help to unlock this for you and help you discover that truly – it’s all connected.

Looking for more like this or want to take next steps? I’m thrilled to announce that I’m offering a new program – Women, Gut, and Soul: The 28-Day Gut-Hormone Reset – a journey through how your gut is central to your hormone health and how to restore gut-hormone balance. We’ll have 4 weeks together to take a deep-dive into gut-hormone health with all the resources you need to create a happy gut, happy hormones lifestyle – including live time with me! Sign up here to join me!