The Gut Bacteria That Control Your Oestrogen Levels

What happens in the gut does not stay in the gut, especially when it comes to hormones.

Most women are aware that oestrogen is produced by the ovaries. Fewer know that the gut plays a significant role in determining how much oestrogen actually circulates in the body at any given time. A review published earlier this year in the journal Nutrients has brought new attention to a mechanism that sits at the intersection of gut health and hormonal health, with particular relevance for women in perimenopause and beyond.

What the oestrobolome is and why it matters

The oestrobolome is the collective name for the gut bacteria that are specifically responsible for metabolising oestrogen. These bacteria produce enzymes that reactivate oestrogen after it has been processed by the liver and sent to the gut for excretion. Once reactivated, that oestrogen is reabsorbed into the bloodstream and put back into circulation.

In practical terms, this means the composition and health of a woman's gut microbiome directly influences how much oestrogen her body retains and uses. A diverse, well-functioning microbiome supports balanced oestrogen recycling. A disrupted microbiome, known as dysbiosis, can push that balance in either direction, contributing to either oestrogen excess or oestrogen deficiency, both of which carry health implications.

What changes at menopause

The review found that menopause is consistently associated with a reduction in gut microbial diversity. This shift mirrors, and may compound, the decline in oestrogen that defines the menopausal transition. Specific bacterial groups that support oestrogen recycling and produce anti-inflammatory compounds decline, while others associated with inflammation and metabolic disruption increase.

These microbial changes have been linked to a range of menopause-associated health outcomes beyond hot flushes and night sweats. The research points to connections between gut dysbiosis and increased cardiovascular risk, reduced bone density, mood changes and genitourinary symptoms. Declining Lactobacillus in the gut after menopause, for example, is associated with changes in vaginal pH that make women more susceptible to infections and genitourinary discomfort.

The review also noted that greater gut microbial diversity is consistently associated with better oestrogen regulation. No single ideal microbial composition has been identified, partly because gut microbiome profiles vary significantly across ethnicities, geographies and dietary patterns.

How diet and lifestyle influence the oestrobolome

The review examined evidence for dietary and lifestyle interventions that may support the gut-oestrogen relationship. Dietary patterns that resemble the Mediterranean diet, characterised by high fibre, fermented foods, vegetables and healthy fats, were associated with improved oestrogen metabolite profiles and reductions in markers of inflammation. Regular aerobic exercise was linked to increased microbial diversity and higher levels of beneficial bacteria including Akkermansia muciniphila.

Specific dietary components showed promise in smaller studies. Prebiotics, including fructo-oligosaccharides and galacto-oligosaccharides, improved calcium absorption and gut microbial balance in postmenopausal women. Phytoestrogens, plant compounds structurally similar to oestrogen found in soy and flaxseed, showed potential to modulate oestrogen metabolism, though effects varied depending on individual gut microbiome composition. Strain-specific probiotics demonstrated early signals of benefit in supporting oestrogen balance, bone health and mood, though the authors are clear that large-scale clinical trials are still needed before firm conclusions can be drawn.

What this does and does not mean

This is a review of existing evidence, not a clinical trial, and the authors are explicit about its limitations. Study populations varied considerably in ethnicity, age and geography, making it difficult to generalise findings. The specific mechanisms connecting gut bacteria to oestrogen metabolism are not yet fully established, and the field lacks longitudinal studies that track diet, microbiome and symptom changes together over time.

What this research does provide is a clear framework for understanding that hormonal health and gut health are not separate concerns. For women navigating perimenopause, the evidence supports prioritising a varied, plant-rich diet and maintaining regular physical activity, not as alternatives to medical treatment but as meaningful contributions to hormonal balance that operate through a biological mechanism that is increasingly well understood.

Reference

Lim MJS, Parlindungan E, See E, Gan CH, Yap R, Yong GJM. Diet, the gut microbiome, and estrogen physiology: a review in menopausal health and interventions. Nutrients. 2026;18(7):1052. doi: 10.3390/nu18071052

Editorial Note

This article is for informational purposes only and is not a substitute for professional medical advice. If you have concerns about your health, speak to a qualified healthcare professional.