The Estrobolome: Your Gut Bacteria Are Running Your Hormones (And They Need a Raise)

Let me guess: you know your gut is important. You've heard about probiotics. You've chugged kombucha. You've nodded knowingly when someone mentioned "gut health" at brunch.

But did you know that a specific collection of gut bacteria is literally controlling your estrogen levels right now?

Yeah. There's an entire microbiome department in your gut—called the estrobolome—whose full-time job is regulating how much estrogen circulates in your body.

And when that department goes rogue? You get PMS, bloating, heavy periods, acne, mood swings, breast pain, endometriosis, fibroids, and a whole menu of hormonal chaos.

Here's what's actually happening inside your body—and why your gut might be the reason your hormones are a mess.

What Is Estrogen, Anyway?

Before we dive into the gut-estrogen connection, let's talk about what estrogen actually is.

Estrogen isn't just one thing. It's a collection of three chemically similar hormones that do way more than you think:

🐱 Estrone (E1)

Produced mainly in your ovaries before menopause, and in your fat tissue and adrenal glands after. This is the dominant estrogen post-menopause.

🐱 Estradiol (E2)

The most abundant and potent form during your reproductive years. It handles breast development, fat distribution, bone health, heart health, memory, cognitive function, and reproductive tissue health. It's also the form of estrogen involved in endometriosis, fibroids, and reproductive cancers.

🐱 Estriol (E3)

The least potent form. Dominant during pregnancy because it's produced by the placenta.

Estrogen is constantly fluctuating—daily and throughout your life. But when it's out of balance, things go sideways fast.

What Happens When Estrogen Goes Rogue?

❌ Too Much Estrogen (Estrogen Dominance):

Irregular periods
Mood swings
Weight gain (especially around your hips and belly)
Headaches and migraines
Acne
Bloating and digestive issues
Increased risk of endometriosis, fibroids, and reproductive cancers

❌ Too Little Estrogen:

Sleep problems
Mood issues (hello, anxiety and depression)
Vaginal dryness
Urinary tract irritation (including more UTIs)
Low libido
Bone density loss
Worse perimenopausal symptoms

So yeah. You want your estrogen levels to be just right. Like Goldilocks and her porridge.

Enter: your estrobolome.

Meet Your Estrobolome: The Microbiome Department Running Your Hormones

Your body is genius. I mean, truly brilliant.

You have an entire specialized team of gut bacteria—called the estrobolome—whose sole job is to regulate your estrogen levels.

Think of it like this: your estrobolome is the quality control department at a factory. Its job is to decide how much estrogen gets recycled back into your bloodstream and how much gets eliminated.

Here's how it works:

You produce estrogen throughout your menstrual cycle (and your whole life).
Estrogen circulates through your body, doing all the important things—keeping your hair shiny, your bones strong, your menstrual cycle regular.
After estrogen does its job, it travels to your liver, where it's broken down into estrogen metabolites and packaged for elimination.
The liver sends this packaged estrogen to your intestines via bile.
Once in your intestines, your estrobolome bacteria decide what happens next.

They produce an enzyme called beta-glucuronidase, which breaks down estrogen into its active forms. Then, your body either: ✔️ Reabsorbs the estrogen back into circulation (if you need more)
✔️ Eliminates it through your stool (if you have enough)

This process is what keeps your estrogen levels "just right."

Your Gut Bacteria Can Also Make Estrogen from Plants

As if this wasn't wild enough, your estrobolome can also create estrogen-like compounds from plant foods.

Certain plant-based foods—like leafy greens, legumes (lentils, chickpeas, tofu), and flaxseeds—contain phytoestrogens, which are plant compounds structurally similar to human estrogen.

Your estrobolome bacteria take these phytoestrogens and transform them into compounds your body can use.

Wait, Isn't More Estrogen Bad?

Good question. You've probably heard about avoiding xenoestrogens—the fake estrogens in cleaning products, plastics, and cosmetics that wreak hormonal havoc.

But phytoestrogens are different. They can actually protect you by:

✔️ Blocking estrogen receptors when your estrogen is too high (preventing excess estrogen exposure)
✔️ Providing gentle estrogen support when your levels are too low

So phytoestrogens are like the Goldilocks of hormones—they help balance things out.

When Your Estrobolome Goes Haywire: The Hormonal Domino Effect

Here's the problem: your estrobolome can only function properly if your gut microbiome is healthy.

And for about 90% of women, it's not.

When your estrobolome is disrupted—through dysbiosis (gut imbalance)—it can't regulate estrogen properly. And that creates a cascade of hormonal chaos.

What happens when the estrobolome malfunctions?

🐾 Bacterial Overgrowth = Too Much Estrogen

When certain bacteria overgrow, they produce excessive amounts of beta-glucuronidase. This means too much estrogen gets reabsorbed back into circulation instead of being eliminated.

The result:

Heavy, painful periods
PMS and mood swings
Cyclic breast pain
Endometriosis
Uterine fibroids
PCOS symptoms
Increased risk of breast and endometrial cancers

🐾 Low Microbial Diversity = Too Little Estrogen

When you don't have enough of the right bacteria, your estrobolome can't: ✔️ Convert estrogen to its active form
✔️ Transform phytoestrogens into usable compounds

The result:

Low estrogen state
Vaginal dryness
More UTIs (because estrogen helps maintain the health of your urinary tract)
Bone density loss
Worse perimenopausal symptoms
Sleep issues
Mood problems

The Estrobolome's Role in Women's Health Conditions

Because estrogen touches so many systems in your body, estrobolome dysfunction shows up everywhere.

🐱 PMS

Estrogen fluctuations create the rhythm of your menstrual cycle. When your gut can't regulate properly, imbalanced estrogen leads to bloating, menstrual migraines, heavy periods, and increased cramps.

🐱 Endometriosis

Research shows that women with endometriosis have higher amounts of bacterial overgrowth in the estrobolome, leading to elevated estrogen that stimulates endometrial tissue growth. Women with endometriosis also have much higher rates of IBS—suggesting a critical gut connection.

🐱 PCOS

Women with PCOS have significantly lower microbial diversity. Dysbiosis contributes to both insulin resistance and increased testosterone production—two hallmarks of PCOS that drive symptoms like acne, hair loss, and unwanted hair growth.

🐱 Cyclic Breast Pain

High estrogen can cause cyclic breast pain. Recent research also shows that your gut microbiome affects the microbiome in your breast tissue—an amazing example of how interconnected your body is.

🐱 UTIs

Estrogen helps maintain the health and integrity of your urinary tract lining. When estrogen is low (due to estrobolome dysfunction), you're more vulnerable to UTIs.

🐱 Reproductive Cancers

Chronic estrogen dominance—driven by estrobolome dysfunction—increases the risk of breast, endometrial, ovarian, and cervical cancers.

What Causes Estrobolome Disruption?

Modern life is basically a recipe for gut dysbiosis. Here's what messes up your estrobolome:

❌ Diet low in fiber, healthy fats, fruits, and vegetables
❌ Diet high in sugar and processed foods
❌ Chronic stress
❌ Overuse of antibiotics (they nuke your good bacteria along with the bad)
❌ Other medications (NSAIDs, birth control, antacids)
❌ Inadequate sleep and circadian rhythm disruption
❌ Sedentary lifestyle
❌ Environmental pollutants (pesticides, herbicides, endocrine disruptors)

The good news? Studies show that you can restore microbiome health in as little as two weeks with the right foods and lifestyle changes.

How to Restore Your Estrobolome (And Your Hormonal Sanity)

Healing your estrobolome isn't about restrictive diets or expensive supplements. It's about giving your gut what it needs to thrive.

🐾 Step 1: Remove Triggers of Bacterial Overgrowth

Sugar: Feeds bad bacteria, promotes inflammation, and crowds out the good guys.
Alcohol: Raises estrogen levels short- and long-term by negatively impacting the estrobolome.
Ultra-Processed Foods: Just 3 days of eating processed foods can wreck your gut. 10-14 days can reduce microbial diversity by 40%.
Environmental Pollutants: Pesticides and herbicides disrupt your microbiome and act as endocrine disruptors. Choose organic when possible.

🐾 Step 2: Feed Your Gut Bacteria with Plant Diversity

Your estrobolome thrives on fiber, phytoestrogens, and plant diversity.

Eat a wide variety of plant foods:
The more diverse your diet, the more diverse your microbiome. Aim for 30+ different plant foods per week.

Up your plant-based fiber:
Leafy greens (especially Brassicas like broccoli, kale, Brussels sprouts, cauliflower, cabbage) are the best food on the planet for your estrobolome. They're packed with fiber and phytoestrogens, and they help eliminate harmful environmental estrogens.

Eat lignan-rich foods:
Lignans are the special fiber that your estrobolome converts into phytoestrogens. Best sources:

Flaxseeds
Lentils
Chickpeas
Whole soy foods (tofu, tempeh, edamame)
Leafy greens

🐾 Step 3: Re-Seed Your Gut with Probiotics

Fermented foods are like a probiotic on steroids. They populate your gut with beneficial bacteria that support estrogen metabolism.

Best sources:

Yogurt (unsweetened, full-fat)
Kefir
Sauerkraut
Kimchi
Miso
Tempeh

Prebiotic foods feed the good bacteria:

Artichokes
Garlic
Leeks
Onions
Asparagus
Beetroot
Green peas
Legumes

Consider a probiotic supplement with at least 10 billion CFUs of Lactobacillus and Bifidobacterium strains. Take it daily for 2-3 months, then scale back to a few days per week if helpful.

🐾 Step 4: Live a Lifestyle That Supports Microbial Diversity

✔️ Get dirty. Play outside. Garden. Touch soil. Exposure to diverse bacteria strengthens your microbiome.
✔️ Exercise daily. Movement supports gut motility, healthy elimination, and hormone balance.
✔️ Sleep 7-9 hours. Your gut bacteria have circadian rhythms too.
✔️ Manage stress. Chronic stress wrecks your gut. Find what works for you—meditation, yoga, walks, therapy.

The Bottom Line: Your Gut Is Running the Show

You can't separate gut health from hormone health. They're completely intertwined.

When your estrobolome is functioning properly: ✔️ Your estrogen levels stay balanced
✔️ Your periods are manageable
✔️ Your mood is stable
✔️ Your skin is clear
✔️ Your risk of reproductive cancers decreases
✔️ You're less vulnerable to UTIs

When it's not? Hormonal chaos.

The good news is that you have more control over this than you think. By supporting your gut with the right foods, lifestyle changes, and targeted supplements (like UTI Biome Shield, which supports both urinary and gut microbiome health), you can restore balance.

Your gut bacteria are working for you 24/7. Give them what they need, and they'll keep your hormones in check.

— Meghan Carozza
Co-Founder & Chief Experience Officer, Good Kitty Co.

References:

Plottel, C.S., & Blaser, M.J. "Microbiome and malignancy." Cell Host & Microbe. 2011.
Kwa, M., et al. "The intestinal microbiome and estrogen receptor-positive female breast cancer." Journal of the National Cancer Institute. 2016.
Flores, R., et al. "Fecal microbial determinants of fecal and systemic estrogens and estrogen metabolites." Journal of Translational Medicine. 2012.
Anderson JW, Baird P, et al. Health benefits of dietary fiber. Nutr Rev. 2009 Apr;67(4):188-205.
Ata B, et al. The endobiota study: comparison of vaginal, cervical and gut microbiota between women with stage 3/4 endometriosis and healthy controls. Scientific Reports. 2019. 9(2204)
Bailey MT, Coe CL. Endometriosis is associated with an altered profile of intestinal microflora in female rhesus monkeys. Hum Reprod. 2002 Jul;17(7):1704-8.
Baker JM, et al. Estrogen-gut microbiome axis: Physiological and clinical implications. Maturitas. 2017 Sep;103:45-53.
Bidisha P, et al. Influences of diet and the gut microbiome on epigenetic modulation in cancer and other diseases. Clin Epigenetics. 2015; 7: 112.
Cotillard A, et al. Dietary intervention impact on gut microbial gene richness. Nature. Volume 500, pages 585–588 (29 August 2013)
David L, et al. Diet rapidly and reproducibly alters the human gut microbiome. Nature. 2014 Jan 23; 505(7484): 559–563.Guo Y, et al. Association between polycystic ovary syndrome and gut microbiota. PLoS One. 2016 Apr 19;11(4):e0153196.
Liu R, et al. Dysbiosis of gut microbiota associated with clinical parameters in polycystic ovary syndrome. Front Microbiol. 2017; 8: 324.
Marco M, et al. Health benefits of fermented foods: microbiota and beyond. Current Opinion in Biotechnology. Volume 44, April 2017, Pages 94-102.
Torres PJ, et al. Gut Microbial Diversity in Women With Polycystic Ovary Syndrome Correlates With Hyperandrogenism. J Clin Endocrinol Metab. 2018 Apr 1;103(4):1502-1511.