Gut Feelings: How Bacteria Can Support You During Perimenopause and Beyond

Ever cried because you felt sad for bacteria? It was late summer and I was researching the impact of our gut microbes on our immune system for an article. Headphones insulating me in my own world as I was making my way along the canal to meet my friend for our weekly Saturday yoga and brunch, listening to a talk on how climate change was eroding bacterial populations in our soil. A sudden deep sense of sorrow conjured up visions of sad puppy-dog faced bacteria lonely and helpless, stranded in the dystopian remains of once fertile ground. The auburn reflections of leaves on water blurred by crocodile tears, I found myself at the comical intersection of hysterically laughing at my own disproportionate despair. I had been having periods long enough to know what was happening and it had very little to do with bacteria or climate change and all to do with this month’s cycle coming to an end. My hormones just plummeted.

Despite the phrase “feeling hormonal,” it’s not an abundance of hormones that causes these emotional swells — it’s the sudden absence of them, especially estrogen and progesterone. While the plight of bacteria had little to do with my feelings at that moment, as it turns out, some bacteria do in fact have a decided impact on our emotional state, especially as it relates to our hormonal balance. I’m referring to the ubiquitous populations of those ancient life forms that call our gut their home. Amongst the myriad of processes they are involved in, is the regulation of estrogen.

To understand how this works, let’s first start by taking a look at the life cycle of estrogen and how it exerts its influence. Estrogen begins its journey in the ovaries, where it is primarily produced in response to signals from the brain’s pituitary gland. These signals, known as luteinizing hormone (LH) and follicle-stimulating hormone (FSH), stimulate the ovarian follicles to secrete estrogen, particularly estradiol, the most potent form. Once released into the bloodstream, estrogen travels to various tissues, binding to specific receptors in organs like the uterus, breasts, brain, bones, and heart, influencing functions such as reproductive health, mood regulation, bone density, and cardiovascular health. After fulfilling its role, estrogen is metabolized in the liver where certain molecules, primarily glucuronic acid or sulfate groups, are added to the estrogen molecules. This conjugation process transforms active estrogens into inactive, more hydrophilic (water-loving) forms, which are then transported into the intestines or filtered by the kidneys for excretion.

In this context, conjugation serves as a detoxification and clearance mechanism for estrogens, helping regulate hormone levels in the body. Once conjugated, these estrogen molecules are rendered inactive, meaning they no longer bind to estrogen receptors or elicit estrogenic effects in tissues.

Now that is all well and good and obviously an important step in our monthly cycle, however as we get older and produce less estrogen, especially as we near menopause, the elimination of what little estrogen we do make can negatively affect our physical, mental, and emotional health. And it is here where we find an unlikely ally: certain strains of bacteria, such as Bacteroides and Clostridia, are capable of producing a key enzyme called β-glucuronidase. This enzyme acts as a gatekeeper, breaking the bond between estrogen and its glucuronic acid group, thereby reactivating it. This process is known as deconjugation. Through this simple yet profound action, estrogen gets a second life — reabsorbed into your bloodstream, ready to perform its duties once again.

You might be familiar with a group of drugs used to treat depression: SSRI or selective serotonin reuptake inhibitors. Those drugs don’t help us make more serotonin, but they help keep more of what we do make available for use and thus can ease symptoms of some forms of depression. Well, those bacterial strains do the same for our estrogen.

It’s like finding treasure in what you thought was discarded. This recycled estrogen goes back into circulation, helping to maintain the delicate hormonal balance that is so crucial, especially as we approach perimenopause. During this time, when estrogen levels naturally begin to fluctuate, the role of your gut microbiome becomes even more pronounced. A healthy, diverse microbiome can ensure that more estrogen is reactivated, easing the transition and potentially reducing some of the more troublesome symptoms of perimenopause — such as mood swings, hot flashes, and bone density loss. It’s almost as if your gut is working behind the scenes to supplement your body with the estrogen it needs, buffering the drop-off in production from your ovaries.

However, this delicate system doesn’t always function smoothly. If the gut microbiome is disrupted — a state known as dysbiosis — the ability to deconjugate estrogen can falter. Dysbiosis often results from factors such as a poor diet, high stress levels, or the use of antibiotics, which kill off the beneficial bacteria responsible for producing β-glucuronidase. Without enough of these bacteria, less estrogen is reactivated, leaving the body in a state of relative estrogen deficiency. For a woman in perimenopause, this could exacerbate symptoms, making the transition into menopause even more challenging.

Conversely, too much of a good thing can also be a problem. If there’s an overabundance of estrogen-deconjugating bacteria, it might lead to excess estrogen re-entering the bloodstream, which can pose its own risks. Elevated estrogen levels have been linked to an increased risk of conditions such as endometrial hyperplasia or even estrogen-sensitive cancers like breast cancer. The balance of gut bacteria is, therefore, crucial — not only to estrogen metabolism but to overall health.

But the connection between gut health and estrogen modulation doesn’t end here, let me introduce you to small but mighty molecules produced by your gut microbiome: short-chain fatty acids (SCFAs). Among these, butyrate stands out as a key player, with the ability to interact with estrogen receptors and potentially help ease the tumultuous symptoms of perimenopause.

Butyrate is not just any byproduct of your gut bacteria; it plays a more active role in your body than you might imagine. As your gut microbes feast on dietary fibers, they produce SCFAs like butyrate. But butyrate doesn’t just hang around in your digestive system — it travels through your bloodstream, reaching vital tissues such as the breast, uterus, and even the brain, where it interacts with estrogen receptors (ERs). In these tissues, estrogen receptors function like switches, turning on or off depending on estrogen’s signals, controlling how different tissues respond to the hormone. When butyrate gets involved, the story gets interesting.

Butyrate’s influence on these estrogen receptors is far more intricate than a simple boost. It acts as a histone deacetylase (HDAC) inhibitor, a fancy term for a process that affects how tightly DNA is packed in cells. By loosening up the DNA, butyrate allows for more transcription of genes that are responsive to estrogen. In essence, it helps amplify estrogen’s effects, making tissues more sensitive to the hormone, which can be particularly beneficial during perimenopause when estrogen levels drop or fluctuate unpredictably. This means that, thanks to butyrate, tissues like the breast, uterus, and brain can still receive a more robust estrogen signal, even when levels of the hormone are declining.

Take the hypothalamus, for instance — a small but powerful region of the brain responsible for regulating body temperature. During perimenopause, as estrogen levels fall, many women experience hot flashes, a sudden wave of heat that can be overwhelming. However, butyrate’s modulation of estrogen receptors in the hypothalamus may help restore some balance, possibly tempering the intensity of these hot flashes.

Estrogen also plays a critical role in mood regulation and cognition, and as its levels fluctuate, women often report symptoms like mood swings, irritability, and memory lapses. Through its modulation of estrogen receptors, butyrate could help keep estrogen signaling strong in the brain, potentially offering some relief from these emotional roller coasters.

Beyond its direct effects on estrogen receptors, butyrate also carries potent anti-inflammatory properties. Chronic inflammation is a known disruptor of hormonal balance, often compounding the challenges of perimenopause. By reducing inflammation, butyrate not only helps stabilize hormone levels but may also alleviate related symptoms such as weight gain and insulin resistance — both common complaints during this stage of life. Improved insulin sensitivity, aided by butyrate, could counter some of the metabolic disturbances that occur with hormonal shifts.

That brings us to the next way in which our friendly microbes may aid in easing the transition through perimenopause: This bustling community plays a crucial role in regulating body weight and metabolism. As hormonal fluctuations begin to reshape our bodies, many notice a creeping change: weight gain, especially around the abdomen, becomes harder to control. This shift is not only frustrating but also intimately tied to how our body produces and processes estrogen.

But there’s more to it than just fewer calories in, more calories out. Adipose tissue — body fat — is not just a passive storage unit for energy. It’s an active participant in hormone regulation. In fact, fat cells themselves can produce estrogen. So, as estrogen levels in the ovaries begin to wane, the body compensates by relying more heavily on estrogen produced in fat tissue. However, this is a double-edged sword: gaining more body fat can increase estrogen levels but also bring along metabolic problems.

Enter the gut microbiome. A balanced, healthy gut — one rich in diverse, beneficial bacteria — helps regulate not only digestion but also body weight and fat distribution. Certain bacteria influence how well your body processes and stores fat, which is especially important during perimenopause when estrogen production becomes more reliant on fat tissue. If your gut microbiome is healthy, it can help keep body weight stable and, in turn, regulate estrogen levels in a more natural, balanced way.

But what happens when this ecosystem falls out of balance? If the gut microbiome tilts into dysbiosis, where harmful bacteria outnumber the beneficial ones, the body’s ability to regulate weight — and by extension, estrogen production — becomes compromised. Dysbiosis can lead to increased fat accumulation, particularly around the waistline, which further stimulates the production of estrogen in fat cells. This excess estrogen can disrupt the delicate balance already in flux during perimenopause, leading to more pronounced symptoms like bloating, weight gain, and insulin resistance. It becomes a cycle that’s hard to break: more fat, more estrogen, more hormonal imbalance.

But when the gut microbiome is healthy, it helps break this cycle. As we already touched upon, through the production of short-chain fatty acids(SCFAs), particularly butyrate, the microbiome aids in maintaining insulin sensitivity and inflammation control — two factors closely tied to weight regulation. Butyrate, for instance, helps the body efficiently metabolize food and fat, preventing the rapid weight gain that is so common during this life stage. This is not just about gut health in isolation; it’s about systemic balance. The gut, through its interaction with hormones and metabolism, can support or hinder the body’s attempts to stabilize during perimenopause.

Furthermore, a healthy gut microbiome can optimize how dietary nutrients are absorbed and how fat is stored. The SCFAs produced when gut bacteria ferment fiber from plant-based foods play a key role in energy homeostasis — how your body manages the calories you consume. This efficient energy use keeps fat storage in check, which can be critical when you struggle with shifting body composition.

Now that we have established how important a healthy and balanced microbiome is as we navigate this hormonal shift, let’s explore how we can ensure we get all the support we need from our allies. To get them to do the work we need them to do, we need to provide them with the best possible conditions and nutrients. It is a two way street. We look after them, then they will look after us.

First and foremost, diet is one of the most powerful tools for supporting a healthy gut microbiome. A plant-rich diet, high in fiber from fruits, vegetables, legumes, and whole grains, fuels the beneficial bacteria in your gut. Fiber acts as a prebiotic, essentially feeding the good bacteria so they can thrive and produce those valuable short-chain fatty acids (SCFAs), like butyrate. Foods such as garlic, onions, leeks, asparagus, and bananas are particularly high in prebiotics and are excellent for promoting bacterial diversity. Regular consumption of these foods can foster a gut environment that supports efficient estrogen reactivation and modulates inflammatory processes.

Fermented foods like yogurt, kefir, sauerkraut, kimchi, and miso also promote a healthy microbiome by introducing probiotics — live, beneficial bacteria — into the gut. Probiotics can help rebalance the microbial community, especially after disruptions caused by factors like stress or antibiotic use. Regular consumption of probiotics, along with prebiotic-rich foods, creates an ecosystem where beneficial bacteria can proliferate, outcompeting harmful strains that might otherwise lead to dysbiosis. Research suggests that specific strains of probiotics, such as Lactobacillus and Bifidobacterium, may improve symptoms related to hormonal imbalances, including mood swings and digestive issues like bloating.

Another crucial factor in maintaining gut health is minimizing the consumption of processed foods, added sugars, and unhealthy fats. Diets high in sugar and refined carbohydrates tend to promote the growth of harmful bacteria, which can disrupt the gut’s ability to efficiently regulate hormones. These foods are also linked to increased inflammation, a condition that not only exacerbates menopausal symptoms but also disrupts insulin sensitivity and metabolic processes, leading to weight gain and energy crashes. Cutting back on these “microbiome disruptors” can help your gut maintain the right environment for optimal hormone balance.

Exercise is another potent modulator of gut health. Studies show that regular physical activity encourages microbial diversity, boosting the population of bacteria associated with better metabolic health and improved immune function. This, in turn, supports hormonal balance. Interestingly, aerobic exercise like walking, swimming, and cycling has been shown to increase the abundance of Akkermansia muciniphila, a beneficial bacterium linked to lower inflammation and improved insulin sensitivity — both of which are important as the body navigates the hormonal shifts of perimenopause. Moreover, exercise promotes gut motility, reducing the likelihood of constipation and the build-up of toxins that could otherwise interfere with estrogen metabolism.

Adequate hydration is also key to maintaining a well-functioning gut. Water facilitates digestion, helps prevent constipation, and ensures that waste products — including excess estrogen — are efficiently eliminated from the body. Without proper hydration, the intestines can become sluggish, leading to a backup of estrogen metabolites and other toxins, which can exacerbate symptoms like bloating and fatigue.

Beyond diet and lifestyle, stress management is an often overlooked yet vital component of gut health. Chronic stress has been shown to alter the gut microbiome by promoting the growth of pathogenic bacteria, disrupting the gut barrier (leading to leaky gut syndrome), and triggering systemic inflammation. High stress can directly impact estrogen levels by influencing how hormones are metabolized and excreted, further exacerbating the rollercoaster of perimenopausal symptoms. Practices such as mindfulness, meditation, yoga, and even regular breathing exercises can reduce stress and help maintain the integrity of the gut lining. Lower stress levels also promote a more diverse and resilient microbiome, which in turn helps regulate hormonal balance.

Finally, it’s important to be mindful of antibiotic use. While antibiotics are sometimes necessary, they can significantly disrupt the balance of gut bacteria by killing both harmful and beneficial strains. If antibiotics are needed, it’s a good idea to follow up with a course of probiotics or increase consumption of fermented foods to help restore bacterial diversity and re-establish gut health. Similarly, nonsteroidal anti-inflammatory drugs (NSAIDs) can negatively impact the gut lining, leading to inflammation and disruption of microbial populations. Limiting unnecessary use of these medications can help protect the delicate balance of the microbiome.

In sum, keeping your microbiome in optimal condition during perimenopause involves a holistic approach that includes a fiber-rich diet, regular consumption of fermented foods, physical activity, adequate hydration, stress reduction, and judicious use of antibiotics and medications. Through these strategies, you can nurture a gut environment that supports your body’s hormonal health, easing the transition through perimenopause and promoting long-term well-being.

Sybille Hazward