Mind-Body Health

The Estrobolome: How the Gut Impacts Estrogen Levels, Metabolism, and More

The Estrobolome: How the Gut Impacts Estrogen Levels, Metabolism, and More
The microbiome has been receiving increasing attention. This collection of microbes on and within your body has wide-reaching impacts on your health, influencing everything from the absorption of nutrients and mood to metabolism and immunity.

Emerging research is shedding light on specific microbes within your gut microbiome, which play a central role in the regulation of hormones—such as estrogen—within the body. This so-called estrobolome influences the metabolism of various forms of estrogen and, therefore, the risk of developing estrogen-related diseases such as endometriosis, breast cancer, and prostate cancer.

The Many Facets of Estrogen

Estrogen plays many vital roles in the human body including influencing the regulation of body fat, female reproductive function, cardiovascular health, bone turnover, and memory function. Estrogen is not just a female hormone and also plays important roles in aspects of men’s health such as the maturation of sperm and maintenance of libido.

A woman’s body produces three main types of estrogen. The different forms of estrogen have different potencies and influence different tissues and functions within the body.

  1. Estrone (E1): Estrone is made mainly in the ovaries before menopause and can be converted into estradiol in the body (and vice versa). Although total estrogens decline overall with menopause, estrone becomes the dominant circulating estrogen post-menopause. It has less potent impacts relative to estradiol (E2).
  2. Estradiol (E2): Estradiol is the major form of estrogen produced in the ovaries in premenopausal women and is also produced by the adrenals and placenta. It is the most potent form of estrogen during the reproductive years in terms of absolute serum levels as well as estrogenic activity. Estradiol plays a key role in the development of female secondary sexual characteristics such as breasts and a feminine pattern of fat distribution. Estradiol is also important for maintaining female reproductive tissues, supporting bone growth, and influencing heart health and memory. This form of estrogen is thought to play a role in diseases such as endometriosis, fibroids and cancers of the uterus, ovaries and breasts.
  3. Estriol (E3): Estriol is the least potent form of estrogen. It is the dominant estrogen during pregnancy since it is manufactured in high quantities by the placenta.
Estrogens are also produced by gut bacteria and can be obtained from the environment as well. Some are produced by plants (phytoestrogens), which may be consumed as food while others are made synthetically (xenoestrogens) and found in common household products such as fragrances, pesticides, and plastics. Toxins such as xenoestrogens are absorbed by the body and stored in the liver and fat cells. They can act additively with endogenously produced estrogens, influence cell proliferation, or otherwise disrupt the hormonal balance of the body.

These different forms of estrogen interact and influence one another in the body, so the overall balance of the major forms and their metabolites plays a key role in modulating disease risk. The ratios of hormones and their appropriate metabolism and excretion impact your risk of inflammatory, autoimmune, and malignant diseases. For example, hormonal balance of estrogen is essential for maintaining healthy cholesterol levels, proper bone density, a balanced mood, and functioning memory.

The Gut-Hormone Connection and the Estrobolome

The human gut microbiome exerts both local and wide-reaching effects. For example, a subset of microbes within the gastrointestinal tract impacts the metabolism of the various forms of estrogens and the balance of circulating and excreted hormone levels. These microbes are collectively referred to as the estrobolome.

Microbes in the estrobolome produce beta-glucuronidase. This enzyme alters estrogens into their active forms, which can bind to estrogen receptors and influence estrogen-dependent physiological processes. In general, the more beta-glucuronidase that the microbes in your gut produce, the less estrogen is excreted out of the body so that more remains within the body to be recirculated, bind to receptors, and exert their influence on various physiologic processes.

When the gut microbes are out of balance (a state known as dysbiosis), beta-glucuronidase activity may be altered. In addition to variable levels of this enzyme activity, intestinal microbial richness overall also influences the balance of estrogens circulating in the body. This dysbiosis can lead to either a deficiency or an excess of free estrogen and imbalances between the various forms of estrogen and other hormones, which may promote the development of estrogen-related pathologies and chronic diseases.

Dysbiosis of the Estrobolome and Chronic Disease

Given the various roles that estrogen plays in the human body, it is not surprising that gut dysbiosis, which alters the estrobolome, has been associated with the development of several chronic diseases. Overall, some of the most common signs of imbalanced estrogen and other hormones include:

  • Bloating and digestive upset
  • Acne
  • Low libido
  • Heavy, light, or irregular periods
  • Tender, swollen, and/or fibrocystic breasts
  • Headaches
  • Weight gain
  • Hot flashes
  • Mood swings
  • Polycystic ovarian syndrome (PCOS)
  • Cancers of the breast, ovaries, or prostate
For example, estrobolome disruption in postmenopausal women is associated with an increased risk of obesity, cardiovascular disease, and loss of bone density such as osteoporosis.

Other research suggests that the estrobolome of both the gastrointestinal tract and vagina in women with endometriosis may have larger numbers of beta-glucuronidase–producing bacteria, leading to increased levels of circulating estrogens and inflammation that drive endometriosis.

Polycystic ovary syndrome (PCOS) is another condition that seems to be influenced by the balance of microbes in the estrobolome. Studies suggest that imbalanced gut microbiota may promote increased androgen biosynthesis and decreased estrogen levels through lowered beta-glucuronidase activity, which contributes to hormonal imbalances characteristic of PCOS.

Emerging research also links dysbiosis of the estrobolome to various forms of cancer. This altered balance of gut microbes leads to increased levels of circulating active estrogens, which promote cell proliferation in estrogen-sensitive tissues such as the breasts, endometrium, cervix, and ovaries.

Balancing Your Estrobolome

The composition of your estrobolome is influenced by many factors including genetics, diet, alcohol intake, environmental exposures, and medications, especially antibiotics. Therefore, you can support a healthy estrobolome and balance of estrogen in your body through a combination of detoxification, diet, and supplementation to encourage the body to restore this delicate balance. It is important to work in conjunction with a knowledgeable provider to individualize an approach that considers your unique body, genetics, and needs.

Eat a Hormone-Balancing Diet

Diet strongly influences the composition of the estrobolome. Several dietary factors may have a positive impact on the estrobolome.

  • Fermented foods such as sauerkraut, kimchi, and kvass help to rebalance gut bacteria and increase diversity.
  • Probiotics strains such as Lactobacillus acidophilus can help decrease bacteria that produce beta-glucuronidase.
  • Prebiotic foods that are rich in fructo-oligosaccharides or inulin help to promote the growth of beneficial bacteria. These include chicory, asparagus, garlic, and banana.
  • Plant-based foods high in dietary fiber (think nuts, seeds, legumes, beans, and a variety of vegetables) support healthy gut bacteria and lead to more balanced levels of estrogen. In this study, avocado and grapefruit were particular standouts.
  • Cruciferous vegetables such as broccoli, cauliflower, cabbage, and kale are helpful in regulating beneficial gut bacteria, supplying fiber to keep the gut healthy and supporting healthy detoxification of hormones including estrogen.

Reduce Toxicity

Many manmade compounds, the xenoestrogens, can mimic natural estrogens in the body as well as alter the composition of the microbiome. There are several steps you can take to reduce your exposure to xenoestrogens in everyday life.

  • Minimize your use of plastics such as plastic water bottles and food containers, especially when heated.
  • Be mindful of what you put on and in your body when it comes to personal care products. Avoid synthetic fragrances, phthalates, and parabens, which can impact estrogen balance.
  • Use all-natural, biodegradable laundry and household cleaning products.
  • Choose unbleached chlorine-free products such as coffee filters, tea bags, sanitary products, toilet paper, and paper towels or switch to reusable organic cotton options when possible.
  • Opt for organic food whenever possible.

Exercise for Hormone Health

Exercise is another great way to support detoxification and reduce stress to keep your hormones balanced. Physical activity helps to balance circulating levels of estrogen in both the short and long term.

Studies suggest that maintaining an active lifestyle throughout life beginning during adolescence may reduce the risk of breast cancer. In addition, regular moderate-intensity exercise can lower levels of circulating estrogens.

When it comes to exercise, more isn’t always better though. Be mindful of what works best for your body and don’t overdo it. Stress, even from positive habits like exercise, can trigger hormonal imbalances as well. Listen to your body, take time for recovery in between workouts, and balance rest with mindful activity.

Lifestyle, nutrition, physical activity, and stress management are all linked to the balance of your hormones. These lifestyle and dietary habits can help you balance your estrobolome and keep your hormones healthy!

*Editor’s Note: The information in this article is intended for your educational use only; does not necessarily reflect the opinions of the Chopra Center's Mind-Body Medical Group; and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health providers with any questions you may have regarding a medical condition and before undertaking any diet, supplement, fitness, or other health program.

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