Can Probiotics and Bacteria Affect Hormones?

Updated: Sep 2

The microbiome is a collection of bacteria located in our gut. We know the types of bacteria in the microbiome can vary greatly from person to person, but is there a connection between our gut bacteria and hormone balance?


The microbiome is found in the the gastrointestinal (GI) tract. A healthy microbiome should be composed of a wide variety of gut bacteria, we're talking over 500 different species. Researchers are working hard to learn more about specific strains, but one thing we know for sure - having a decreased variety of bacterial strains in the microbiome is linked with disease and imbalances in the body.


Hormonal imbalance in women is an increasingly common issue and is correlated with symptoms, including: weight gain, bloating, fatigue, headaches, mood swings, depression, and more. Knowing the link between the microbiome, specifically the estrobolome, and our hormones allows us a tool for treatment. There is so much we can do through nutrition and lifestyle to promote a diverse microbiome, therefore we can use these techniques as part of our treatment for hormone balance. In this article we will focus specifically on the estrobolome.



If you are interested in learning more about hormones, you can find my free download on "Understanding Hormone Imbalances" by visiting the Hormone Hub page.


In this article we will focus on supporting the health of the estrobolome for hormone balance.

Keep in mind, there are many factors in our life that can disrupt hormone balance. These factors include chemicals and toxins found in our environment through the air, water, personal care products, cleaning products, fragrances, and more. We also can disrupt hormones through changes in our diet, lifestyle, and most importantly stress - both physical and emotional stress.



What is the Estrobolome?


The estrobolome is a collection of bacteria in the microbiome who's primary role is to metabolize estrogens (1). These specific bacteria regulate the excretion and circulation of estrogen back into the body. Therefore, these bacteria play an important role in estrogen levels.


There are three main forms of estrogen produced in the body.

  1. Estradiol (E2) is predominant in non-pregnant women prior to menopause

  2. Estrone (E1) is predominant after menopause

  3. Estriol (E3) is highest during pregnancy



How is excess estrogen excreted from the body?


Estrogens circulate in the blood in order to travel to tissues and organs for different functions. The liver is in charge of pulling out excess estrogen and estrogen metabolites out of the blood. The estrogens bind to detoxification enzymes, known as conjugation. Conjugated estrogens are excreted in bile, urine, and bowel movements.


Researchers found that a significant amount of conjugated estrogens are actually reabsorbed back into the blood's circulation. Why is this?


What they found was that these conjugated estrogens can be de-conjugated by certain bacterial species that produce ß-glucuronidase, an enzyme. Once the estrogen is de-conjugated it can enter back into circulation (2). A healthy gut microbiome has an estrobolome that produces the right amount of beta-glucuronidase to maintain estrogen balance in the body. When the microbiome becomes imbalanced it can lead to either an increase or decrease of estrogens present in the body.



What is the role of estrogen in the body?


There are many functions of estrogen, but here are a few of the most important. Estrogen regulates body fat composition, reproductive function in women, cardiovascular health, bone density, and cell growth. An unhealthy microbiome can alter the estrobolome, disrupt estrogen balance, and impair these vital functions in the body.


Well known conditions linked with estrogen imbalance in women include: endometriosis, PCOS, obesity, cardiovascular disease, osteoporosis, and estrogen dominant cancer.



Wondering what you can do to promote a healthy microbiome and estrogen balance?


What can you do to promote a healthy microbiome and estrogen balance?


The microbiome can be affected by diet, lifestyle, medications, exercise, stress, and genetics.


Both, antibiotics and hormonal birth control have been found to alter gut bacteria and estrogen levels (3,4). These findings suggest antibiotics and hormonal birth control medications can also have a negative effect on the estrobolome.


Diet plays a large role in the estrobolome activity. Studies have shown that strict vegetarians have increased fecal excretion of conjugated estrogens compared with non-vegetarians, leading to decreased estrogen levels in the body (5).


A U.S. study compared 10 premenopausal women consuming a “Western diet” (high fat, low fiber) with 10 premenopausal vegetarians (high fiber, moderate fat). The vegetarians had 3-times the estrogens excreted in feces and 15-20% lower estrogen levels in the body." (1)


Diet recommendations for a healthy estrobolome and hormone balance


Fiber is an important part of a healthy diet as well as a healthy functioning estrobolome. The recommended intake for fiber in the U.S. is 25 grams per day, but I always encourage my clients to aim for at least 30 grams of fiber daily. Fiber should come from whole food, plant sources. Below are some of my favorite high-fiber foods.


Keep in mind when you are increasing fiber in your diet it is extremely important to drink an adequate amount of water. The general rule of thumb is to drink half your body weight (lbs) in ounces of water. For example, if you weigh 160 pounds you will want to drink 80 ounces of water per day. Water and fiber are also key in the diet for regular, daily bowel movements.


Pumpkin and flax seeds contain phytoestrogens, which are the plant's natural estrogen. Phytoestrogens help to support estrogen balance, as well as help to clear excess estrogen from the body to prevent imbalance. You can add 1-2 tablespoons seeds to your oatmeal, smoothie, yogurt, or just snack on by themselves.


Probiotics are another factor in a healthy estrobolome. When choosing a probiotic, it should be from a reputable company that is third-party tested. A serving should provide at least 5 billion CFUs (colony forming units). Bacterial strains that are being studied in their relationship to the estrobolome include: Lactobacillus gasseri, Lactobacillus reuteri, and Saccharomyces boulardii. You can find some of my favorite probiotics by Metagenics here.



High Fiber Foods:

  • 2 Tbsp. Chia Seeds = 10 g fiber

  • 2 Tbsp. Flaxseed = 6 g fiber

  • 1 cup Raspberries = 8 g fiber

  • 1/2 Avocado = 5 g fiber

  • 1 cup Broccoli = 5 g fiber

  • 1 medium Pear = 5 g fiber

  • 1/4 cup Almonds = 4 g fiber

  • 1/2 cup Lentils = 8 g fiber

  • 1/2 cup Black Beans = 7 g fiber

  • 2 cups Leafy Greens = 3 g fiber

  • 3 cups Popcorn = 4 g fiber



Keep in Mind: Natural support of hormone balance takes time. It may be a few months before you see any change or benefit. I recommend tracking your monthly cycle and symptoms, so you can monitor changes. If you are interested in additional support and guidance you can always reach out to me by filling out this short inquiry form.




Interested in taking next steps to balancing hormones and healing your gut? Check out my Hormone Hub group program!


Liz Riesen, Registered Dietitian

specializes in digestive and hormone imbalances. Often these conditions coexist and share common disruptive symptoms including mood changes, bloating, pain, irregular cycles, inflammation, and more. Liz is trained in identifying and healing food sensitivities, as well as balancing hormones naturally through nutrition and lifestyle.


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