The Gut - Hormone Connection: What Every Woman Should Know

Your gut and hormones are in constant conversation - here’s how to support them both.

At the recent Inside Out Microbiome & Gut Health Festival in London, I spoke about the powerful, two-way conversation between women’s hormones and the gut.

For many women, gut health and hormone symptoms are treated as separate issues. But science now shows they are deeply linked - and understanding that connection can change everything.

Meet Your Inner Ecosystem

Your gut is home to trillions of microbes - more than the number of stars in the Milky Way. These microbes do far more than digest food. They influence inflammation, immunity, mood, and even how hormones like oestrogen and progesterone behave in the body.

A specific group of microbes, called the estrobolome, helps manage oestrogen levels by deciding how much is cleared and how much is recycled. When balanced, this system supports smooth hormonal rhythm. When disrupted - e.g. by stress, antibiotics, low-fibre/high processed food diets, or poor sleep - excess oestrogen can recirculate, leading to oestrogen dominance and symptoms like heavier & more painful periods, sore boobs, bloating, and/or mood swings.

We often think these symptoms are just normal or something we have to put up with - but they can actually be signs that something’s out of balance. It’s your body’s way of talking to you, asking for support and a little more attention to what’s happening inside.

Progesterone: The Gut’s Stop–Go Hormone

Progesterone naturally relaxes the smooth muscles of the gut, slowing digestion slightly. Some women can be sensitive to this hormone and experience constipation, bloating, or a heavier feeling in the second half of their cycle, when progesterone is at its highest.

Then, in the days leading up to a period, progesterone levels drop sharply and compounds called prostaglandins start to rise. Prostaglandins are hormone-like substances that help the uterus contract to shed its lining - but they don’t just act on the womb. They also affect the muscles of the digestive tract, increasing contractions and speeding things up.

This can contribute to looser stools, cramps, or diarrhoea just before or during a woman's period - as the gut is responding to those same inflammatory signals.

Progesterone and Mood: The Calming Connection

When broken down, progesterone produces allopregnanolone (Allo-P) - a neuroactive compound that interacts with GABA receptors in the brain, helping to calm the nervous system and reduce anxiety. Think of it as the body's natural chill pill!

Interestingly, certain gut microbes can metabolise progesterone into Allo-P and related compounds, meaning your microbiome can also contribute to how effectively this calming pathway works.

When progesterone levels fall - before a period or during perimenopause and menopause - levels of Allo-P drop too, which can trigger low mood, irritability, anxiety, or disrupted sleep.

Because the gut plays a role in metabolising and signalling these compounds, supporting your gut health can help promote a more stable, resilient mood throughout the month and during hormonal transitions.

Simple Ways to Support Both

Small, consistent steps make a big difference.

Eat for diversity – aim for 30+ plant foods weekly (this includes herbs and spices).

Stay hydrated – 1.5–2 L water daily helps fibre do its job and keeps the gut mobile.

Include prebiotics – e.g. onions, garlic, asparagus and pulses feed the "good guy" microbes.

Add probiotics – kefir, live yoghurt, kimchi, or sauerkraut (if tolerated) contain good bacteria.

Love your liver – cruciferous veg like broccoli, rocket, and cabbage help clear oestrogen. Manage stress & sleep – key regulators of the gut–brain–hormone axis.

Move daily – gentle activity keeps your gut moving and microbes thriving.

Stay Connected

I’ll be starting a 3-week online Balance Your Hormones course in the new year - designed to help women in perimenopause rebalance energy, mood, and digestion through simple, practical steps.

If you’d like to find out more, just send me a message at bernadette@roarnutritionist.co.uk or via Instagram @roarnutritionist.