Jul 246 min read

Demystifying Estrobolome: Gut Health and Estrogen Balance

Photo of a woman making a heart shape with her hands over her gut. — Support your gut health through your menopause journey.

From the onset of puberty until menopause, women experience a menstrual cycle and changes in hormone levels over approximately 28 days.

This cycle prepares your body for pregnancy by thickening the walls of your uterus. In the absence of a pregnancy, menstruation occurs as the uterine lining is shed (1, 2).

The menstrual cycle is chiefly managed by estrogen, a key sex hormone that plays a vital role in the female body, from developing breast tissue and other sexual characteristics, to supporting bone density, and decreasing coronary artery disease risks (3).

What Is the Estrobolome?: The Gut Microbiome

The term “estrobolome” refers to genes of gut microbes encoding beta-glucuronidases and beta-glucosidases, enzymes responsible for the metabolism and bioavailability of hormones.

In simple terms, the estrobolome refers to "gut bacteria" that play an important role in how estrogen is processed and utilized in your body.

These genes encode enzymes that impact the metabolism and availability of estrogen, which can influence various aspects of your health, including a hormone balance and potential risks for certain diseases.

A cyberpunk depiction of a uterus. — Source: Estrogen Society

Stages of the Menstrual Cycle

The menstrual cycle is divided into two primary phases:

Follicular Phase
Luteal Phase

Follicular Phase:

During the follicular phase, the first half of the cycle, estrogen prepares your uterus for ovulation as follicles containing egg cells mature (1).

During ovulation, a surge in luteinizing hormone (LH), triggered by high estrogen levels breaks the mature follicle and releases the oocyte (1).

Luteal Phase:

In the luteal phase, the final half of the menstrual cycle, progesterone becomes the dominant hormone, preparing your uterus and corpus luteum for the implantation of a fertilized ovum.

Estrogen and progesterone levels begin to rise mid-luteal phase and are maintained if a pregnancy occurs. If pregnancy does not occur, hormone levels quickly drop, leading to menstruation (1, 4).

What Are the Forms of Estrogen?

Estrogen is not a single hormone, but rather a group of hormones with four major forms (5).

Estrone (E1): A weaker form produced by the ovaries, adrenal glands, and adipose tissue, becomes the primary form produced postmenopause (5, 6).
Estradiol (E2): The strongest and most potent form produced by the ovaries which matures and maintains the female reproductive system. The primary estrogen during reproductive years, but levels decrease during menopause (5).
Estriol (E3): A form produced by the ovaries which sensitizes and prepares the mother’s body for pregnancy and labor. Primarily produced during pregnancy, but also exists and near-undetectable levels outside of pregnancy (7).
Estetrol (E4): A recently discovered form produced during pregnancy by the human fetal liver with a currently unclear function (14).

Chemical Structure of Estrogen. Source: Natural Cycles

Why Is It Important to Maintain Estrogen Levels?

Estrogen levels impact your entire body, with imbalances leading to a range of symptoms. Low levels can manifest as:

Menstrual periods stopping or becoming irregular
Dry skin
Hot flashes
Difficulty sleeping
Low libido
Vaginal thinning and dryness
Mood swings
Insulin Resistance

High estrogen levels can result in:

Abnormal menstrual bleeding and other menstrual issues
Weight gain
Fibrocystic breast
Fibroids in the uterus
Worsening premenstrual syndrome
Loss of libido
Fatigue
Feelings of depression or anxiety (5).

Imbalances have also been linked to several acute and chronic diseases, including breast cancer, fertility issues, obesity, and cardiovascular disease (8).

Chart of the estrogen pathway. — The estrogen pathway (8)

How Can I Support The Metabolism of Estrogen?

For those experiencing menopausal symptoms due to low estrogen levels, hormone replacement therapy is a common treatment.

Foods, herbs, and supplements with a natural supply of phytoestrogens, substances found in plants and animals with a structure similar to estrogen, offer a natural approach (9, 10).

Plant-based sources containing phytoestrogens such as:

Soy
Legumes
Grains
Oilseeds
Peas
Red Clover
Kimchi

Can help support and rebalance the estrobolome. (10,11)

The relevance of phytoestrogens to diet and gut microflora is of particular interest to researchers, as estrogen metabolism occurs in the gut’s estrobolome (12).

Image of healthy foods. — Source: UCLA Health

What Is Osteoporosis?

Osteoporosis is a condition characterized by weakened bones that are more prone to fractures. It is often referred to as a "silent disease" because there are usually no symptoms until a fracture occurs.

Oestrogen and Your Bones

Osteoporosis is a significant health concern, especially for postmenopausal women, as estrogen plays a crucial role in maintaining bone density.

Estrogen helps regulate the activity of osteoblasts and osteoclasts, the cells responsible for building and breaking down bone tissue. When the levels of this hormone decline, as in menopause, there is an accelerated breakdown of bone tissue, leading to osteoporosis.

Image of Healthy Bones vs Osteoporosis — Healthy Bones vs Osteoporosis. Source: National Institute of Aging

Why Is It Important to Support the Estrobolome?

By understanding and supporting the estrobolome through diet and lifestyle choices, it may be possible to positively influence estrogen levels and overall well-being.

With a replenished estrogen supply circulating throughout your body, this process ensures the menstrual cycle can proceed smoothly (13).

Impacts of Imbalanced Estrobolome

An imbalanced or unhealthy estrobolome, caused by factors such as your diet and lifestyle, can lead to hormonal imbalances and health issues, making it crucial to maintain a healthy estrobolome for your overall health and hormonal balance.

Image of estrogen pathway — The mechanism by which estrogen penetrates the bloodstream. (13)

Estrobolome and Menopause, What is the Correlation?

During menopause, the composition of the gut microbiome changes, decreasing its diversity to become more similar to the microbiomes of men’s guts.

Levels of beta-glucuronidases, a key enzyme in the estrobolome’s metabolism of estrogen, and the bacteria producing them are decreased in premenopausal women and even more so in postmenopausal women (19).

What Does This Mean In Terms of Your Health?

With fewer enzymes being produced that are able to deconjugate estrogen, less can enter the bloodstream, decreasing the amount that the body can utilize.

Research is ongoing, but studies indicate that the influence of menopausal changes on the estrobolome can result in adverse cardiometabolic profiles in both premenopausal and postmenopausal women (19).

When Will I Start Menopause?

Most women begin menopause around age 45-55, with perimenopause beginning in the mid 40's. However, this is different for everyone and could be different for you. For a more accurate estimation, join the waitlist for our time-to-menopause predictor to prepare for your transition!

What Is Dysbiosis?

Imbalances in the gut’s community of microorganisms, known as dysbiosis, can manifest as an overall loss, gain, or change in the abundance of bacterial species (15).

What Causes Dysbiosis? From Diet to Antibiotics:

Alcohol Consumption
High Sugar Diets
Stress
Medications
Environmental Factors

Outcomes of Dysbiosis: Overgrowth of Bacteria

Dysbiosis can lead to overgrowth of harmful bacteria and impact the estrobolome, leading to reduced deconjugation of estrogen and lower the levels circulating in the bloodstream (17).

What Health Risks Are Associated With Dysbiosis?

Such an imbalance places multiple systems throughout the body at risk, including the immune system and its ability to regulate immunity, as well as the GI tract and its crucial role in digestion and nutrient absorption.

Other Health Risks Include:

Cancer
Pregnancy complications and adverse outcomes
Endometriosis
Polycystic ovarian syndrome (PCOS) (16)

Can You Reverse Dysbiosis With Probiotics and Prebiotics?

There are a number of techinques being researched to reverse Dysbiosis as well as probiotics and prebiotics, such as:

Fecal Transplantation
Bariatric Surgery
Pharmaceutical Interventions

How Can I Optimize the Function of the Estrobolome?

Some studies have shown that eating phytoestrogen-rich foods can help balance estrogen levels, minimizing menopausal symptoms (11).

Natural Remedies To Protect The Estrobolome

Maintaining a healthy lifestyle such as physical activity
Maintaining a healthy diet
Avoiding stressors
Reducing exposure to harmful chemicals

Tools such as MenoTime can provide valuable, personalized insight into best practices to prepare for and minimize effects of hormonal changes experienced during the menopausal transition.

Image depicting the intestine — Source: Cellabeauty

The Importance of Estrogen

Estrogen, a vital hormone for the menstrual cycle and women’s reproductive health, is metabolized by enzymes encoded by genes within intestinal microbes, linking gut health directly to reproductive health and risk factors.

A complete understanding of the estrobolome and its role in the enterohepatic circulation of estrogens requires more research; however, its central role in mood regulation provides exciting future directions in the holistic treatment of women’s health.

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