How can gut microbiome play a role in improving women’s health?

Over the past decade, conversations around gut microbiota and its many benefits have skyrocketed. Evidently, this symbiotic population has functions that are essential to the maintenance of our general health, but it also represents opportunities for therapeutic applications. Amongst the many systems orchestrating our bodies, the gut microbiota has proven to be closely related to the endocrine system, responsible for the production, release and modulation of hormones. But why is such a relationship particularly interesting for female health? In this article, Alcimed takes a closer look at the impact of the gut microbiome on the female body.

The fundamental role of balanced estrogen levels for women’s health

What are estrogens?

Estrogens are one of the key hormones for women, not only for sexual characteristics, but also for their role in bone health, sex drive, cognitive health, and cardiac functioning, amongst other aspects. Their synthesis occurs both in gonadal sites, and in extragonadal organs such as the brain and the kidney, and their circulating levels will fluctuate not only across a lifetime but also from one day to another.

There are three major forms of estrogens:

• Estrone (E1),
• Estradiol (E2),
• Estriol (E3).

Each is present in different proportions throughout women’s lives, depending on their reproductive status and age.

For premenopausal and reproductive women, E2 predominates. During a menstrual cycle, which lasts 28 days on average, E2 levels should rise and fall twice, once during the follicular phase and another during the luteal phase. In turn, E3 plays its bigger part during pregnancy as it is produced in larger quantities and can be used as a biomarker of fetal health and well-being. During the menopausal changes, perimenopausal women will experience ebbs of estrogens until production falls to a very low level. After menopause, E1 will be the major player.

What are the effects of estrogens on women’s health?

As a general rule of thumb, higher levels of estrogens can result in bloating, breast tenderness, and heavy bleeding, whereas lower levels can result in hot flashes, night sweats, palpitations, headaches, insomnia, fatigue, and bone loss. As these are only a few aspects affected by the fluctuation of estrogens levels, their monitoring is key for female health.

The impact of gut health on female hormones: the role of the estrobolome

Within the gut microbiota, some bacteria will be capable of modulating the metabolism of estrogens through the secretion of β-glucuronidase, an enzyme responsible for breaking down estrogens into their active forms. In fact, only these active forms of estrogens can then bind to their receptors and trigger the subsequent physiological cascade. This collection of gut bacteria which have the privilege, and great responsibility, to interact with a hormone as important as estrogen is called “the estrobolome”.

In the event of an imbalance in these gut bacteria, commonly called gut dysbiosis, this interaction is impaired and the levels of circulating estrogens will be affected. This alteration can greatly impact health aspects including mood, libido, and weight, but most importantly contribute to the development of conditions such as obesity, endometriosis, polycystic ovary syndrome, fertility, and cardiovascular disease. For example, women with polycystic ovary syndrome have different gut microbiota profiles compared with healthy women.

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The estrogen-gut microbiome axis: a way to improve women’s gut microbiome

In recent years, researchers have characterized the bridge between the gut microbiota and the estrogen hormone as “the estrogen-gut microbiome axis”. This route between a population of bacteria and the estrogen hormones seems to be a key regulatory pathway of circulating levels of estrogens. Most importantly, this route goes both ways: the gut microbiome has also been shown to be influenced by estrogens [3]. As menstrual cycles, pregnancy, or menopause can be unsettling times for women, this bidirectional route between gut microbiome and estrogens is an actionable bridge for prevention and therapy. To ensure optimal function and cohabitation between all actors, maintaining a healthy gut is essential.

In addition to a healthy lifestyle and diet, probiotics and/or prebiotics can alleviate some painful gastrointestinal symptoms by acting on the estrobolome. For example, during menstrual cycles probiotic supplementation can help reduce diarrhea and bloating.
In the case of pregnancy, probiotic supplementation has been proven to be safe. Still, its positive effects on the mother’s and infant’s health remain to be fully grasped but some great opportunities lie ahead.
In the case of menopause probiotics can address bloating, gas, abdominal pain and irregular bowel movements along with other symptoms. Finally, recent studies have shown motivating results to target estrogen-mediated diseases via the gut microbiota.

There are many therapeutic opportunities to discover and to unveil under this estrogen-gut microbiome axis. With a fast-growing and aging population, giving women healthy and customizable tools to support them in their life cycles is paramount. If your organization is interested in exploring such areas, Alcimed is here to support you. Don’ hesitate to contact our team!

About the authors, 

Thaïs and Lucia, Consultants in Alcimed’s Life Sciences team in Switzerland