The Gut–Brain Axis

Screenshot 2026-01-21 at 3.13.41 PM

Why Your Gut and Brain Are Always Talking

Have you ever felt a “gut feeling” or butterflies when you’re nervous? That’s because your gut and brain are constantly communicating.

This connection – called the gut–brain axis plays a role in digestion, mood, stress, sleep, immunity, hormones, and mental health.

What Is the Gut–Brain Axis?

The gut–brain axis is the communication network between:

  • Your brain and spinal cord (central nervous system)
  • Your gut’s nervous system (often called the “second brain”)

This two-way system explains why stress can affect digestion, and why gut issues can influence mood and wellbeing.

How Do They Communicate?

Your gut and brain stay connected through:

  • The vagus nerve: A major nerve acting like a direct phone line between the gut and brain.
  • Chemical messengers (neurotransmitters): These help regulate digestion, stress responses, and emotional balance.
  • The gut microbiome: Trillions of microbes in your gut that produce signals affecting both gut and brain function.

The Gut Microbiome: More Than Digestion

Your gut microbes do much more than help digest food. They influence:

  • Immunity
  • Inflammation
  • Hormones
  • Metabolism
  • Mental health

A healthy gut microbiome is diverse, balanced, and stable.

Why Gut Health Affects Mood

About 90% of the body’s serotonin is made in the gut. While this gut serotonin doesn’t directly control mood, it:

  • Keeps digestion moving smoothly
  • Regulates gut sensitivity and pain
  • Helps explain why gut conditions and anxiety often occur together

Stress can disrupt gut function — and gut irritation can send distress signals back to the brain.

Gut Health and the Immune System

Around 70% of the immune system lives in the gut. When gut health is compromised, this can contribute to:

  • Increased allergies
  • Lower immunity
  • Histamine-related symptoms (rashes, headaches, congestion, bloating)

Supporting Your Gut–Brain Axis

Strong foundations matter:

  • Eat a diverse, nutrient-rich diet
  • Move your body regularly
  • Prioritise quality sleep
  • Manage stress effectively

Stress doesn’t just affect your mind – it can also change your gut microbiome.

The Big Picture

Your gut isn’t just for digestion. It’s a key communication hub influencing how you feel, think, and function.

Because everyone’s gut is unique, understanding your individual gut health is an important step toward long-term balance and wellbeing.

If you have ongoing digestive, immune, or stress-related symptoms, a personalised gut health assessment may help identify what your body needs.