I’ll never forget the day I made the connection. I was sitting in my dentist’s chair, getting yet another reminder about flossing (guilty as charged), when it hit me: why had no one ever told me that what’s happening in my mouth could be messing with my hormones?

Here’s the truth that most healthcare providers miss: your oral microbiome directly influences your hormonal balance. The bacterial communities living in your mouth can translocate to your gut and fundamentally alter how your body metabolizes critical hormones like estrogen. We’re talking about real effects on your metabolism, your mood, your energy—basically everything that makes you feel like yourself.

Let me break this down in a way that actually makes sense.

Your Mouth and Gut: One Continuous Ecosystem

Think about this for a second: your mouth is literally the beginning of your digestive system. It’s not some separate entity—it’s the entrance to one long, continuous mucosal surface that runs from your lips all the way through your entire GI tract.

And here’s what blew my mind when I first learned this: those bacteria living in your mouth? They don’t just stay put. Every time you swallow (which happens about 2,000 times a day, by the way), you’re sending oral bacteria down into your gut.[1,2]

Now, when you have periodontal disease or you’re skipping that nightly floss routine (no judgment—we’ve all been there), pathogenic bacteria start colonizing your gut. Once they set up shop in your intestinal environment, they disrupt the delicate balance of commensal microorganisms that are supposed to be regulating your hormone metabolism.

This microbial imbalance—what scientists call dysbiosis—doesn’t just stay in your gut. It triggers cascading effects throughout your entire body.[3] And yes, that includes your hormones.

Meet the Estrobolome: Your Hormone-Regulating Microbiome

Okay, this is where it gets really fascinating. (And trust me, I know “fascinating” and “gut bacteria” aren’t words you usually see in the same sentence!)

Inside your gut lives this specialized collection of bacteria that scientists have dubbed the “estrobolome.” I like to think of it as your hormone’s personal management team. This bacterial community has one main job: regulating estrogen, one of your body’s most important hormones.[4,5]

And estrogen? It’s not just about reproduction. This hormone affects:

• Your bone strength (preventing osteoporosis)
• Heart health
• How your body uses energy and stores fat
• Your mood and brain function (yes, this is why hormone changes can mess with your head)

Here’s the cool part: The bacteria in your estrobolome produce enzymes (particularly one called beta-glucuronidase) that can activate or deactivate estrogen in your body.[6]

When these bacteria are balanced, your hormone levels stay in that sweet spot. But when things get out of balance—what doctors call dysbiosis—your hormones can go haywire.[7] And that’s when you start experiencing all those “fun” symptoms like irregular periods, mood swings, stubborn weight gain, and exhaustion that no amount of coffee can fix.

How Your Gut Microbiome Actually Regulates Hormones

Let me walk you through what’s happening in your body right now. Your liver processes estrogen (making it less active), then sends it to your intestines.

Here’s where your gut bacteria become super important. They can make one of two choices:

1. Let that estrogen leave your body
2. Reactivate it so it goes back into your bloodstream

That beta-glucuronidase enzyme I mentioned? This is when it does its job. It basically “turns on” the estrogen again so your body can reuse it—a process called enterohepatic circulation.[8,9]

When this system works properly, your estrogen levels stay balanced. But when things go sideways? That’s when the hormone problems start.

When Your Gut Bacteria Get Out of Balance

I’ve seen this happen with so many women. When your gut bacteria become imbalanced (doctors call this dysbiosis), it throws off your entire hormone system. And the consequences? They’re real, they’re frustrating, and they’re more common than you think.[10,11]

Here’s what can happen:

Polycystic Ovary Syndrome (PCOS): Hormonal imbalance, insulin resistance, and ovarian issues. If you’ve been diagnosed with PCOS, there’s a good chance your gut bacteria are playing a role.

Endometriosis: This painful condition where tissue grows outside the uterus—research is showing strong connections to gut imbalance.

Estrogen-related cancers: Changes in how your body processes estrogen may increase cancer risk. Your estrobolome matters here.

Weight and metabolism issues: Can’t lose weight no matter what you try? Your gut bacteria affect insulin, fat storage, and energy use. It’s not all in your head—it might be in your gut.

Mood problems: Hormonal ups and downs affect brain chemicals. If you feel like you’re on an emotional roller coaster, your microbiome might be driving it.

The research is clear: gut imbalance can change your estrogen levels by affecting that beta-glucuronidase enzyme activity. Too much or too little estrogen can lead to health problems.[12,13]

Bottom line? Your gut bacteria are literally controlling your hormone levels.

The Oral-Gut Connection: Why Your Dentist Should Be Talking About This

Here’s what really gets me: your mouth has the second-largest bacterial community in your entire body (only your gut has more). And these oral bacteria? They don’t just hang out on your teeth and gums. They’re actively traveling to your gut and changing your intestinal bacteria.[14,15]

I know this sounds kind of gross, but stick with me—this is important.

The Oral-Gut-Estrobolome Axis

Scientists have a name for this connection: the “oral-gut-estrobolome axis.”[16] Before your eyes glaze over, let me explain what this means for you:

It’s basically a communication loop:

• Bacteria from your mouth travel to your gut (every time you swallow)
• Your gut bacteria directly affect how your body processes estrogen
• Your estrogen levels then influence both your mouth and gut bacteria

When you have gum disease or poor oral hygiene, harmful bacteria from your mouth move to your intestines. Once they’re there, they disrupt your estrobolome and throw off your hormones.[17,18]

The Specific Bacteria Causing Problems

Research has identified some specific troublemakers—two bacteria with scientific names: Porphyromonas gingivalis and Fusobacterium nucleatum.[19,20]

These bacteria cause gum disease in your mouth. But when they reach your intestines, they:

• Increase inflammation in your gut
• Disrupt your beneficial gut bacteria
• Interfere with estrogen processing
• Contribute to diseases throughout your body, including heart disease and cancer

So yeah… flossing suddenly seems a lot more important, doesn’t it?

What This Means for Your Health

Understanding this connection between your mouth, gut, and hormones is important because it means:

1. Taking care of your mouth helps your whole body: Brushing your teeth, flossing, and seeing your dentist regularly doesn’t just prevent cavities – it protects your gut and helps keep your hormones balanced.[21]
2. Gut health affects hormone health: Eating foods that support good gut bacteria (like fruits, vegetables, and fermented foods) can help keep your hormones balanced.[22]
3. Everything is connected: Your body is one big system where everything affects everything else. You can’t have good hormone health without good gut health, and you can’t have good gut health without good oral health.

Signs Your Oral-Gut-Hormone Axis Might Be Out of Balance

You might have an imbalance if you experience:[23,24]

Oral symptoms:

• Bleeding gums when you brush or floss
• Bad breath that doesn’t go away
• Loose teeth or receding gums
• Frequent cavities despite good hygiene

Gut symptoms:

• Bloating, gas, or digestive discomfort
• Irregular bowel movements
• Food sensitivities that seem to come out of nowhere

If you have symptoms in more than one of these categories, your oral-gut-hormone axis might need support!

The Bottom Line

Your body is an amazing, connected system. The bacteria in your mouth can affect the bacteria in your gut, which can control your hormones, which can affect your overall health. It’s all connected like one big circle!

The simple act of brushing your teeth isn’t just about having a nice smile – it’s about supporting your entire body’s health. When you understand this connection, you can make better choices about your oral care, your diet, and your overall health.

In our next post, we’ll share natural solutions to protect your oral microbiome and balance your hormones – including ancient practices like oil pulling, which products to avoid, and exciting new personalized testing options that can tell you exactly what YOUR unique body needs.

Remember: everything in your body is connected. Your mouth, your gut, and your hormones all work together as a team. When you support one, you support them all!

Here’s to your gut health, hormone balance and vitality!

Warmest,
Lori 

References

1. Bull MJ, Plummer NT. Part 1: the human gut microbiome in health and disease. Integr Med (Encinitas). 2014;13(6):17-22.
2. Rajasekaran JJ, Krishnamurthy HK, Bosco J, et al. Oral Microbiome: A Review of Its Impact on Oral and Systemic Health. Microorganisms. 2024;12(9):1797. doi: 10.3390/microorganisms12091797.
3. Costa CFFA, Correia-de-Sá T, Araujo R, et al. The oral-gut microbiota relationship in healthy humans: identifying shared bacteria between environments and age groups. Front Microbiol. 2024;15:1475159. doi: 10.3389/fmicb.2024.1475159.
4. Baker JM, Al-Nakkash L, Herbst-Kralovetz MM. Estrogen-gut microbiome axis: Physiological and clinical implications. Maturitas. 2017;103:45-53. doi: 10.1016/j.maturitas.2017.06.025.
5. Kumari N, Kumari R, Dua A, et al. From Gut to Hormones: Unraveling the Role of Gut Microbiota in (Phyto)Estrogen Modulation in Health and Disease. Mol Nutr Food Res. 2024;68(6):e2300688. doi: 10.1002/mnfr.202300688.
6. Ervin SM, Li H, Lim L, et al. Gut microbial β-glucuronidases reactivate estrogens as components of the estrobolome that reactivate estrogens. J Biol Chem. 2019;294(48):18586-18599. doi: 10.1074/jbc.RA119.010950.
7. Plottel CS, Blaser MJ. Microbiome and malignancy. Cell Host Microbe. 2011;10(4):324-335. doi: 10.1016/j.chom.2011.10.003.
8. Kwa M, Plottel CS, Blaser MJ, Adams S. The Intestinal Microbiome and Estrogen Receptor-Positive Female Breast Cancer. J Natl Cancer Inst. 2016;108(8):djw029. doi: 10.1093/jnci/djw029.
9. Parida S, Sharma D. The microbiome-estrogen connection and breast cancer risk. Cells. 2019;8(12):1642. doi: 10.3390/cells8121642.
10. Peters BA, Lin J, Qi Q, et al. Menopause is associated with an altered gut microbiome and estrobolome, with implications for adverse cardiometabolic risk in the Hispanic Community Health Study/Study of Latinos. mSystems. 2022;7(3):e00273-22. doi: 10.1128/msystems.00273-22.
11. Qi X, Yun C, Sun L, et al. Gut microbiota-bile acid-interleukin-22 axis orchestrates polycystic ovary syndrome. Nat Med. 2019;25(8):1225-1233. doi: 10.1038/s41591-019-0509-0.
12. Sun Y, Gao S, Ye C, Zhao W. Gut microbiota dysbiosis in polycystic ovary syndrome: Mechanisms of progression and clinical applications. Front Cell Infect Microbiol. 2023;13:1142041. doi: 10.3389/fcimb.2023.1142041.
13. Chadchan SB, Singh V, Kommagani R. Female reproductive dysfunctions and the gut microbiota. J Mol Endocrinol. 2023;70(1):e220177. doi: 10.1530/JME-22-0177.
14. Baker JL, Mark Welch JL, Kauffman KM, McLean JS, He X. The oral microbiome: diversity, biogeography and human health. Nat Rev Microbiol. 2024;22(2):89-104. doi: 10.1038/s41579-023-00963-6.
15. Tian N, Faller L, Leffler DA, et al. Oral Microbiome in Human Health and Disease. mLife. 2024;3(3):287-305. doi: 10.1002/mlf2.12136.
16. Tatullo M, Nor J, Orrù G, et al. Oral-Gut-Estrobolome Axis May Exert a Selective Impact on Oral Cancer. J Dent Res. 2024;103(5):461-466. doi: 10.1177/00220345241236125.
17. Zhang Y, Wang X, Li H, et al. Menopausal shift on women’s health and microbial niches. NPJ Womens Health. 2025;3:11. doi: 10.1038/s44294-024-00050-y.
18. Schmidt TSB, Raes J, Bork P. The Human Gut Microbiome: From Association to Modulation. Cell. 2018;172(6):1198-1215. doi: 10.1016/j.cell.2018.02.044.
19. Tanwar H, Gnanasekaran JM, Allison D, et al. Unravelling the oral-gut axis: interconnection between periodontitis and inflammatory bowel disease, current challenges, and future perspective. J Crohns Colitis. 2024;18(8):1319-1341. doi: 10.1093/ecco-jcc/jjae028.
20. Mima K, Nishihara R, Qian ZR, et al. Fusobacterium nucleatum in colorectal carcinoma tissue and patient prognosis. Gut. 2016;65(12):1973-1980. doi: 10.1136/gutjnl-2015-310101.
21. Rajasekaran JJ, Krishnamurthy HK, Bosco J, et al. Oral Microbiome: A Review of Its Impact on Oral and Systemic Health. Microorganisms. 2024;12(9):1797. doi: 10.3390/microorganisms12091797.
22. Shoer S, Shilo S, Godneva A, et al. Impact of dietary interventions on pre-diabetic oral and gut microbiome, metabolites and cytokines. Nat Commun. 2023;14:5384. doi: 10.1038/s41467-023-41042-x.
23. Afzaal M, Saeed F, Shah YA, et al. Human gut microbiota in health and disease: unveiling the relationship. Front Microbiol. 2022;13:999001. doi: 10.3389/fmicb.2022.999001.
24. Collden H, Landin A, Wallenius V, et al. The gut microbiota is a major regulator of androgen metabolism in intestinal contents. Am J Physiol Endocrinol Metab. 2019;317(6):E1182-E1192. doi: 10.1152/ajpendo.00338.2019.