The Gut-Hormone Connection: How The Gut Influences Women's Health

The gut–brain–hormone connection

Our gut microbiome is now recognised as a full-fledged endocrine organ. These trillions of bacteria are not just responsible for helping us digest food, but they actively communicate with our hormones, influencing everything from our menstrual cycles to our mood¹.

The oestrobolome is a particularly interesting area of research. This collection of gut bacteria produces an enzyme called beta-glucuronidase, which determines how much oestrogen circulates in our bodies². When our gut bacteria are balanced, they help regulate oestrogen metabolism and excretion, supporting healthy hormone levels. However, when we have dysbiosis, which means the balance of gut bacteria is disrupted, it can lead to excess oestrogen, potentially triggering or worsening conditions such as fibroids and endometriosis.

I noticed this connection when I adopted a fibre-rich, plant-based diet and saw an improvement in my menstrual cycles. By improving my gut health and insulin sensitivity, this helped to regulate my previously unpredictable cycles. The changes were gradual but really transformed my quality of life, including reduced menstrual pain, improved energy levels, clearer skin and more regular cycles.

How PCOS affects your gut

Living with PCOS means dealing with far more than irregular or absent periods. The insulin resistance, inflammation and hormonal fluctuations can feel overwhelming. Women with PCOS often experience gut-related symptoms that result from the underlying connection between hormonal issues and digestive health. When researchers examine stool samples from women with PCOS, they consistently find lower bacterial diversity and higher numbers of bacterial colonies such as Prevotella, which are associated with excess androgens and insulin resistance.

The good news is that our gut is remarkably forgiving. Making dietary changes to include more nourishing whole plant foods allows beneficial bacterial colonies to return. Many clients improve their irregular periods, acne, weight issues and insulin resistance through targeted gut-health interventions.

Common gut symptoms in PCOS

Many women with PCOS report digestive symptoms that can be persistent and affect quality of life. If these symptoms feel familiar, you’re not alone. Addressing gut health can make a real difference:

• Persistent bloating and gas
• Alternating constipation and diarrhoea
• Irritable bowel syndrome (IBS is significantly more common in women with PCOS)
• Brain fog and fatigue after eating
• Increased food sensitivities

These issues often stem from dysbiosis, which fuels inflammation and worsens insulin resistance - the main driver of PCOS symptoms. This creates a frustrating cycle: poor gut health aggravates PCOS, while hormonal imbalance further disrupts digestion. The less diverse microbiome seen in conditions like IBS may also increase psychological comorbidities, explaining why anxiety and depression are more common in women with PCOS.

Endometriosis: A chronic pain condition

Endometriosis affects at least 1 in 10 women. This chronic inflammatory condition occurs when tissue similar to the lining of the womb grows outside the uterus, for example in the pelvis or the bowel, causing a number of symptoms and often severe pain.

The gut connection works through several pathways:

• The oestrogen connection, where imbalanced gut bacteria produce excess beta-glucuronidase, increasing circulating oestrogen that can fuel endometrial tissue growth⁵
• Inflammatory cascade, where changes in gut bacteria trigger systemic inflammation, creating an environment where endometriosis thrives
• Immune system disruption, since the gut microbiome trains our immune system; dysbiosis can impair natural killer cell activity that normally helps control misplaced endometrial tissue

Many women with endometriosis also experience IBS-type symptoms, sometimes due to endometriosis on the bowel, and sometimes because pelvic pain and pelvic floor dysfunction impact gut function.

Diversity of plants: The 30-plant challenge

Research from the American Gut Project found that people with the healthiest gut microbiomes eat at least 30 different types of plants weekly. A 2015 study in the Journal of Nutrition confirmed that those eating a varied diet had a much lower risk of metabolic disease - crucial for long-term PCOS management^3,4.

How to count your plant points:

• 1 point each: fruit, vegetables, legumes (beans, lentils, peas), whole grains, nuts and seeds
• ¼ point each: herbs and spices

A top tip is to fill your plate with colour. Only one in ten people in the UK meet the recommended fibre target of 30g daily, with the average intake around 18g. Whole plant foods are the simplest route to hit fibre targets, since animal foods contain no fibre and ultra-processed foods contain minimal fibre.

Here are some top tips to increase plant diversity:

• Mix fresh and frozen: frozen blueberries often retain more anthocyanins and are brilliant for convenience - keep berries, kale and peas on hand
• Batch cook with variety: a vegetable-rich curry or stew can contain 8–10 plant points; add greens and fresh herbs for extra points
• Explore root vegetables: swap half your potatoes for sweet potatoes, parsnips or butternut squash, rich in beta-carotene
• Switch up your grains: try quinoa, barley or buckwheat instead of always relying on bread and rice

Probiotics: A promising addition

The growing understanding of the gut–hormone connection has led to innovation in probiotics. Evidence shows potential benefits:

For PCOS, clinical trials and reviews report improvements in insulin resistance, hormonal balance (including increased SHBG and reduced testosterone), inflammation markers and some metabolic parameters. Synbiotics, combinations of probiotics and prebiotics, often show stronger effects.

For endometriosis, emerging studies suggest some probiotic strains may reduce pain and inflammation, with Saccharomyces boulardii showing promise in reducing inflammation and pain sensitivity⁵.

Practical steps

Supporting your gut microbiome requires progress, not perfection. Here are my top tips:

1. Feed your beneficial bacteria

• Prebiotic-rich foods: garlic, onions, leeks, asparagus, Jerusalem artichokes
• Fermented foods: kimchi, sauerkraut, kefir, miso, tempeh
• Aim for diversity: track 30 plants weekly as a challenge

2.  Make strategic swaps

• Include more plant protein such as tofu, tempeh, beans and lentils. Even small shifts from animal to plant protein can reduce chronic disease risk and support hormonal health.

3. All the lifestyle pillars matter

• PCOS is heavily influenced by lifestyle; national and international guidelines recommend lifestyle changes as first-line management:

• • Move after meals: a 15-minute brisk walk helps curb blood sugar peaks
  • Try resistance training: useful for reducing androgen excess
  • Prioritise sleep: aim for 7–9 hours
  • Manage stress: yoga, meditation, journaling or social time
  • Prioritise social connection and minimise toxic substances

4. Consider targeted supplementation

• Look for probiotic strains with evidence:
  • Lactobacillus acidophilus and L. gasseri
  • Bifidobacterium species
  • Saccharomyces boulardii
• Food and drink sources of probiotics and prebiotics are usually the best place to start.

5. Work with your cycle

• Support your gut differently across the cycle:
• • Menstrual phase: extra probiotics and anti-inflammatory foods such as turmeric and ginger
  • Follicular phase: focus on diverse fibres and fermented foods
  • Luteal phase: support bowel function with water, fibre-rich fruits, vegetables, intact wholegrains, legumes, nuts and seeds

The power of consistency

Gut symptoms often worsen during hormonal transitions. As oestrogen levels change throughout the cycle, or decline during perimenopause and menopause, digestion may slow and constipation can become more likely. Hormonal fluctuations can also cause diarrhoea for some. The gut microbiome shifts during these phases, which is why symptoms often vary across the cycle.

While plant-rich nutrition can reduce symptoms, focus on all lifestyle pillars for overall wellbeing. Spend time with your support network, move in ways that bring you joy, and be patient with yourself.

Looking ahead

Understanding the gut–hormone connection transformed how I approach health and how I support clients. A healing journey is not linear, but every probiotic-rich meal, nature walk and laugh with friends positively influences your hormones. Your gut and hormones are in constant dialogue - support one and you support the other. Small, consistent changes often yield the biggest results, with gut improvements sometimes seen within days of including probiotic and fibre-rich foods.

Whether you start by adding one new plant food each week, taking a post-meal walk, or simply paying attention to how your gut feels across your cycle, you are taking steps towards better hormonal health.

References

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