The Gut-Brain Axis and Anxiety

How the conversation works

The gut and brain are connected by the vagus nerve, hormones and immune signals. Gut bacteria even help make neurotransmitters such as serotonin and GABA that influence calm and alertness. When this system is disrupted, anxiety and digestive symptoms can reinforce each other.

Why it matters for anxiety

People with anxiety more often report gut problems such as IBS, and stress reliably changes the microbiome. This does not mean anxiety is "all in the gut" — but it does mean caring for your gut is a legitimate part of caring for your mind. Learn more in how gut health affects anxiety.

Which comes first: anxiety or gut symptoms?

Usually neither, cleanly — the gut-brain axis runs both directions at once. A stressful patch can trigger gut symptoms via the vagus nerve and stress hormones, while an unsettled gut can send its own distress signals upward and lower your tolerance for stress. In practice this means chasing a single root cause is often less useful than treating the loop itself: calming the nervous system helps the gut, and settling the gut helps the nervous system.

Practical ways to support both

• Eat a diverse, fibre-rich diet with some fermented foods.
• Protect sleep and move daily — both shape the microbiome.
• Use nervous-system tools like slow breathing to calm the gut from the top down.

For balanced information on diet and mental health, see the Mental Health Foundation. Persistent gut symptoms deserve a GP visit.