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The Surprising Link Between Gut health and Hormones

The Surprising Link Between Gut health and Hormones

Written by Jonathan Bailor, CEO SANESolution & Reviewed by Dr. Matthew Olesiak, MD Chief Medical Director, SANESolution





It’s hard to believe that just a few years ago, scientists believed the role of gut bacteria was limited to digestive health. Now, a large body of research suggests that their influence extends far beyond the gut and may affect your overall health in many ways.

For example, scientists have discovered that:

  • 95% of serotonin is produced and stored in the gut.(1) Serotonin is a neurotransmitter that carries signals between neurons in the brain. It regulates mood, cognitive function, sleep cycle, and much more.
  • 70% of the immune system is located in the gut (gastrointestinal tract). Certain cells lining the gut excrete large quantities of antibodies into the gut that appear to affect disease states in the body.(2)
  • Bacteria in the gut affect metabolism, which can ultimately impact your ability to lose weight or maintain a healthy weight.


And it doesn’t stop there.

Every day it seems that scientists discover another function of gut bacteria that goes far beyond the gut. The effect of gut microbiome on hormones and hormonal balance is one recent discovery.

What is the Gut Microbiome?

The gut microbiome is the community of microbes (microbiota) residing in your gut. There are trillions of microbes in your gastrointestinal tract, 90% of which are bacterial.(3) This community is composed of a diverse blend of bacteria, fungi, viruses, and protozoa that have a beneficial and detrimental impact on human health.

The key to good health is maintaining a balance of “good” and “bad” bacteria, with the good kind outnumbering the bad. As only about 10% of gut bacteria are thought to be detrimental and the remaining 90% beneficial,(4) this shouldn’t be a problem.

But poor quality diet, advancing age, environmental toxins, stress, and other factors can contribute to an imbalance of gut microbiota known as gut dysbiosis.

Signs of an Unhealthy Gut

The biggest cause of an unhealthy gut (dysbiosis ) is regularly eating heavily processed foods, sugars, refined carbs, bad fats, and drinking alcohol. Taking antibiotics can also lead to dysbiosis, as these medications kill both the good and bad bacteria in your gut.

Symptoms of an unhealthy gut vary widely and may include:

  • Frequent gas, bloating, and/or belching
  • Stomach pain/cramps
  • Frequent heartburn
  • Food sensitivities
  • Chronic halitosis (bad breath)
  • Brain fog
  • Mood disorders, i.e., anxiety, depression
  • Sinus congestion
  • Diarrhea
  • Constipation
  • Candida
  • Skin problems, i.e. acne, rosacea
  • Eczema
  • Immune system disorders
  • Allergies
  • Headaches

Diseases and health conditions associated with poor gut health include:

  • Obesity
  • Irritable bowel syndrome (IBS)
  • Inflammatory bowel diseases, i.e. ulcerative colitis, Crohn’s disease
  • Celiac disease
  • Diabetes
  • Leaky gut syndrome
  • Colorectal cancer
  • Heart disease
  • Polycystic ovary syndrome
  • Liver disease
  • Parkinson’s disease
  • Dementia

But how does gut health affect your hormones?

The Gut-Hormone Connection

Hormones are the body’s chemical messengers. They are produced and secreted into the bloodstream by the endocrine system, a collection of glands that control, manage, and coordinate specific bodily functions. Every cell in the body has hormone receptors to facilitate this communication.

Hormones help maintain body temperature, metabolism, cognitive function, blood glucose levels, sexual function, and much more. Without them, your body couldn’t function.

The hypothalamus in the brain has long been considered the sole controller of the endocrine system. However, recent research suggests that the gut microbiome may be a “virtual endocrine organ”. That is, the gut not only produces hormones directly, but it also tells the endocrine glands how much of each hormone should be produced and secreted.(5)

Thus, your gut microbiome affects nearly every hormone in the body. Let’s take a look at just 3 of them: estrogen, thyroid, and melatonin.

How Microbes Influence Estrogen Levels

Researchers have discovered that the gut microbiome houses a collection of microbes called the estrobolome that is able to metabolize estrogens,(6)  which means it can modify the body’s circulating estrogen.

Specifically, microbes in the estrobolome produce beta-glucuronidase, an enzyme that transmutes estrogen into its active form so that it can connect to estrogen receptors. This enables it to modulate estrogen-dependent bodily functions.

The estrobolome is responsible for producing the correct amount of beta-glucuronidase. If it produces too much or too little, as can occur with dysbiosis, a hormonal imbalance of estrogen can occur. This may eventually lead to estrogen-related diseases and conditions.(7)

Gut Health and Estrogen-Related Diseases

Estrogen is the primary female sex hormone, though it’s found in smaller amounts in men. In women, estrogen is responsible for the development and maintenance of the reproductive system and secondary sexual characteristics, i.e. breasts, pubic hair.

As a woman, you’ve likely experienced how fluctuating estrogen levels affect your mood and menstrual cycle. You see it in the mood changes that occur during menstruation, pregnancy, and menopause.

But estrogen does much more than that. For instance, this hormone is crucial for bone health. In fact, estrogen regulates bone turnover and helps prevent bone loss. (8) It’s also necessary for heart health, as it defends against inflammation of blood vessels and helps control cholesterol levels.(9)  There is even evidence that estrogen facilitates healthy brain function.(10)

Given its wide range of physiological functions, estrogen-related diseases are much more common and wide-spread than you might think, and they affect both men and women.

Estrogen’s Link to Type 2 Diabetes

For example, one of the most common endocrine diseases is type 2 diabetes, a condition in which the body cannot properly respond to insulin. When this occurs, cells in your muscles, fat, and liver cannot absorb enough glucose from your blood. This causes chronically elevated blood glucose levels that if not reversed can progress to type 2 diabetes.

Research suggests that estrogen may help the cells respond to insulin. But if dysbiosis occurs and affects estrobolome function, it could impair your cells’ ability to react to insulin’s command.

This could be one of the reasons why postmenopausal women are at increased risk of developing type 2 diabetes. If a dysfunctional estrobolome reduces circulating estrogen, it could further reduce the already greatly diminished estrogen levels, leaving her vulnerable to this disease.(11)

Estrogen Involved in Diseases Common in Women

Estrogen has also been shown to play an important role in many diseases common in women, including weight gain/obesity, cardiovascular disease, osteoporosis, and breast cancer. Menopause is thought to increase the risk of these diseases. (12), (13), (14), (15) 

Though more research is needed, it is clear that imbalanced gut microbiota can negatively affect the estrobolome, resulting in impaired estrogen levels that may increase the risk of many diseases.

Gut Microbiome and Thyroid Hormones

The thyroid gland, that butterfly-shaped organ located in the lower front of the neck, is essential for life. Thyroid-stimulating hormone (TSH), excreted by the pituitary gland, stimulates the thyroid gland to make triiodothyronine (T3) and thyroxine (T4).

These thyroid hormones affect every tissue in your body and perform several essential functions. For instance, they help regulate the heart rate, body temperature, brain function, and metabolism.

Altered composition of gut bacteria is associated with high TSH levels. If you have too much TSH, your body may produce lower levels of T3 and T4.(16) This can lead to hypothyroidism or underactive thyroid. Hypothyroidism can increase the risk of obesity, cardiovascular disease, and other conditions.

Gut Microbiome and Melatonin Levels

Melatonin is a hormone your brain produces in response to darkness. It regulates your wake/sleep cycle, called the circadian rhythm. To make a sufficient amount of melatonin, however, your brain needs plenty of serotonin, the majority of which is made by bacteria in your gut.(17)

Also, it appears that insufficient sleep can be the cause and the effect of low melatonin levels. Research suggests that chronic sleep deprivation can negatively affect the composition of gut bacteria, leading to dysbiosis.(18) This can result in a reduction of serotonin-producing bacteria, thereby reducing melatonin production.

This same alteration in gut microbiome may also contribute to bodily inflammation, raising the risk of metabolic syndrome, obesity, and type 2 diabetes that is often observed in sleep-deprived individuals.(19)

How to Improve Gut Health and Hormones

Here are a few ways to naturally improve gut health and hormonal balance.

Adjust Your Diet

Reducing the amounts of processed foods, starchy carbs, and sugars you eat will help heal your gut and improve hormonal regulation. Good dietary choices include plant-based foods, high-quality proteins, and healthy whole-food fats. Incidentally, a high-fiber diet has been shown to significantly improve the gut microbiome.(20)

Replace Your Probiotics with a Daily Postbiotic Supplement

Adding a postbiotic supplement to your diet is a great way to have a healthy gut.

Though probiotic supplements are all the rage, research suggests that postbiotics are a better choice. That’s because probiotics typically contain just a few bacterial strains that may not significantly improve microbial balance or overall health.

By contrast, postbiotics are metabolites produced from bacterial fermentation of fiber in the lower colon. Experts believe they may be responsible for most of the health benefits commonly attributed to fiber intake. In other words, postbiotics may provide many more health benefits than those of probiotics.

There are thousands of different postbiotic metabolites, but one that offers the most gut-healing benefits appears to be TRIButyrate, a patented form of butyrate. Time-released TRIButyrate transports butyrate to the lower colon where it’s needed to repair your gut and to provide far-reaching health benefits.

Reduce Stress

Studies show that chronic stress is not only bad for your health in general, but it also alters your gut microbiome. Some ways to reduce stress include walking, meditating, practicing yoga, spending time in nature, listening to relaxing music, getting a massage, or playing an instrument.

The Gut and Hormonal Balance

Multiple research studies show a clear link between a healthy gut and proper hormone function, which in turn affects overall health. Fortunately, gut health and hormonal issues are easy to correct. All it takes is a healthy diet, the right postbiotics supplement, and taking time to relax and enjoy life.






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2- Fields H. The Gut: Where Bacteria and Immune System Meet. Johns Hopkins Medicine. Nov 2015. Accessed Jul 18, 2021. https://www.hopkinsmedicine.org/research/advancements-in-research/fundamentals/in-depth/the-gut-where-bacteria-and-immune-system-meet

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