Premenstrual Syndrome (PMS) affects many women in the days leading up to their menstrual cycle. Symptoms can include mood changes, bloating, fatigue, headaches and digestive discomfort.

Although PMS is primarily linked to hormonal fluctuations during the menstrual cycle, researchers are increasingly exploring how the gut microbiome may influence hormone metabolism and inflammation during this time.

The gut microbiome — the trillions of microorganisms living in the digestive system — interacts closely with immune cells, metabolic pathways and hormone signalling. Scientists are now studying how microbiome balance may influence the way hormones such as oestrogen are processed in the body.

Understanding this connection may help explain why gut health is becoming an important area of interest in research into hormonal wellbeing.

Founder Insight

Hanna Sillitoe first became interested in the role of the gut microbiome while naturally treating her psoriasis. During this time she began exploring research into how gut bacteria influence inflammation, digestion and immune responses.

This experience sparked a long-standing interest in how the microbiome may influence many aspects of health, including hormone balance and overall wellbeing.

What Is PMS?

Premenstrual Syndrome (PMS) refers to a group of physical and emotional symptoms that occur in the luteal phase of the menstrual cycle, typically in the days leading up to menstruation.

Common PMS symptoms may include:

• mood changes or irritability
• fatigue
• bloating
• breast tenderness
• headaches
• digestive changes

These symptoms are believed to be linked to natural fluctuations in hormones such as oestrogen and progesterone during the menstrual cycle.

Hormonal shifts can influence many systems in the body, including the nervous system, immune responses and metabolism. Because the gut microbiome interacts with these systems, researchers are exploring how microbiome balance may influence hormonal wellbeing.

The Gut Connection

The Microbiome and Hormone Metabolism

The gut–hormone axis describes the relationship between the gut microbiome and the endocrine system.

Certain gut bacteria are involved in metabolising hormones such as oestrogen through a group of microbes known as the estrobolome.

Oestrogen metabolism

After oestrogen is processed by the liver, it enters the digestive tract where gut bacteria influence whether it is excreted or reabsorbed into circulation.

This means the microbiome may influence how oestrogen circulates in the body.

The gut–brain axis

The gut microbiome also interacts with the nervous system through the gut–brain axis, which links digestive processes with mood and neurological signalling.

Because mood changes are common during PMS, researchers are exploring how microbiome signalling may influence emotional wellbeing.

Inflammation and immune signalling

The microbiome plays an important role in regulating immune responses. Changes in microbiome composition may influence inflammatory pathways that interact with hormonal signalling.

What Research Shows

Scientific interest in the microbiome and hormone health has grown rapidly in recent years.

Research findings include:

• The estrobolome and oestrogen metabolism – Certain gut bacteria influence how oestrogen is metabolised and recycled in the body.

• Microbiome diversity and hormone regulation – Studies suggest that microbiome diversity may influence metabolic and hormonal processes.

• Gut–brain signalling – The microbiome produces compounds that interact with the nervous system and may influence mood and stress responses.

• Inflammation and hormone balance – Because the microbiome regulates immune signalling, imbalances in gut bacteria may influence inflammatory pathways linked to hormone health.

Although research is still developing, these findings highlight the growing interest in how microbiome balance may influence hormonal wellbeing.

Sources

Plottel CS & Blaser MJ. Microbiome and estrogen metabolism: the estrobolome. Cell Host & Microbe, 2011.

Baker JM et al. Estrogen–gut microbiome axis: physiological and clinical implications. Maturitas, 2017.

Cryan JF & Dinan TG. Mind-altering microorganisms: the impact of the gut microbiota on brain and behaviour. Nature Reviews Neuroscience, 2012.

Sender R et al. Revised estimates for the number of human and bacterial cells in the body. PNAS, 2016.

Supporting the Microbiome

Maintaining a healthy and diverse microbiome may help support hormonal balance and overall wellbeing.

Eat a diverse range of plant foods

Plant diversity provides fibre and nutrients that help nourish beneficial gut bacteria.

Increase fibre intake

Fibre acts as fuel for gut microbes and supports the production of beneficial metabolites.

Include fermented foods

Fermented foods such as sauerkraut, kefir and kimchi contain naturally occurring microorganisms that may help support microbiome diversity.

Maintain healthy lifestyle habits

Sleep, stress management and regular physical activity can influence microbiome balance and hormone health.

Consider probiotic support

Some people choose to support their microbiome with probiotics — live microorganisms designed to help maintain microbial balance within the digestive system.

Common Questions About PMS and Gut Health

Can gut health affect PMS symptoms?

Researchers are exploring how the gut microbiome may influence hormone metabolism, inflammation and gut–brain signalling, all of which may play roles in PMS.

What is the estrobolome?

The estrobolome refers to a group of gut bacteria involved in metabolising oestrogen within the digestive system.

Can probiotics support hormone balance?

Some studies have investigated how probiotics may influence microbiome diversity and immune regulation. Research in this area is ongoing.

Conclusion

PMS is influenced by natural hormonal fluctuations that affect many systems throughout the body, including mood, metabolism and digestion.

Increasingly, research suggests the gut microbiome may play a role in hormone metabolism, immune signalling and gut–brain communication.

Supporting a healthy and diverse microbiome through diet, lifestyle habits and microbiome support may therefore help maintain balance within the complex systems that influence hormonal wellbeing.

Some people choose to support their microbiome with probiotics — live cultures designed to help maintain a healthy balance of gut bacteria. Learn more about our Multi-Strain Biotic and how it supports gut health.