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Anxiety and Stomach Issues: The Gut-Brain Connection


Often when we experience stomach issues, the first thing we do is think back on what we last ate. Whilst diet can play a huge role in affecting how you feel, many other lifestyle factors can also contribute. Anxiety can be a huge contributor to gut issues. Being under stress puts your gut under stress (think about that ‘butterfly’ feeling in your stomach when you get nervous).

This is a great example of the gut-brain connection!

New leading-edge science is discovering that brain health (and therefore brain diseases) are dictated by what goes on in the gut to an extraordinary degree. That’s right, your gut health dictates your brain health and this is why the gut is often referred to as the “second brain”. This connection is involved in stomach acid production, inflammation, immune function, hormone production, neurotransmitter production, and much more.

Here are 5 ways your gut can impact your brain and vice versa:

  • Neurotransmitters (brain chemicals like serotonin)

  • Dysbiosis (bad bugs in our gut)

  • Leaky gut (research has shown if you have a leaky gut you have a leaky brain!)

  • Stress/anxiety

  • Hormone imbalances

Stress and anxiety sometimes trigger the overactivity of your gut.⁠ When you're stressed or scared, your brain sends a "fight or flight" signal to your gut, which results in your digestion being affected and causing stomach issues such as bloating, constipation, and other digestive issues.

Understanding anxiety:

Anxiety can dramatically affect our ability to function well at home, at work, or in social situations. While the causes of anxiety are varied, it’s helpful to identify potential triggers, practice mindfulness, and use stress-relief techniques to try to overcome them. It is important to note that there are physical and emotional symptoms of anxiety.

Physical Symptoms of Anxiety Look Like:

• Tight chest

• Increased heart rate

• Nausea, upset stomach

• Sweating

• Difficulty concentrating

Emotional Symptoms of Anxiety Look Like:

• Feeling Overwhelmed About the Future

• Fixating on the worst-case scenarios

• Overthinking

• Feeling Irritable/ On Edge

• Being Restless

Why does anxiety make one's stomach so upset?

When you are anxious, stress hormones flood your body, entering your digestive tract and interfering with digestion. When your brain thinks there is a real threat and the stress response, "fight-or-flight" is activated, your body may temporarily halt digestion because this is not a top priority when your body thinks it needs to keep you alive and goes in "surviving" mode. This response increases blood flow to the heart (leading to a racing heartbeat) and lungs (leading to hyperventilation), causing the stomach to not be able to function as effectively as it normally would.

Anxiety may cause you to tense up your stomach muscles without you even realizing it. This can lead to digestive upset, especially if you tense your stomach while eating. Eating heavy, inflammatory foods can decrease good gut bacteria and this, combined with your stress hormones is not a good mix.

Understanding the gut and brain connection:

Research shows that the more diverse the bacteria in your gut microbiome is, the less likely you are to have stress and anxiety. That’s because neurotransmitters—chemical messengers your body can’t function without—made in your digestive tract travel up to your brain, having a direct impact on your mood. The signals created by your brain can then return to your digestive tract, creating a gut/mind feedback loop that can make or break your mental well-being.

Did you know that 90% of serotonin is produced in the gut? Serotonin is our “feel-good” hormone. It’s made from the amino acid tryptophan (mostly found in meat), and low levels of serotonin can lead to symptoms such as depression, anxiety, and other mood disorders. It’s so important we fuel our gut microphones with proper nutrients. When your gut isn’t functioning properly, it can hugely impact your mood.

Understanding anxiety and gut’s relation:

When we experience prolonged stress and anxiety the stress hormones and chemicals that are helpful with short-term stressors (cortisol, etc) become toxic. This then results in the microorganisms in your gut being prevented from working properly.

Trauma and anxiety can leave us in a state of 'hyperarousal' or "'hypervigilance' therefore meaning our cortisol and adrenaline levels don't return to an equilibrium causing more anxiety and stress, and the cycle repeats.

Some of the ways this might manifest in the gut are:

  • Indigestion

  • Upset stomach or diarrhoea

  • Irritable Bowel Syndrome (IBS) and bloating

  • Constipation

  • Strange and fluctuating appetite

  • Nausea

Because the nervous system in the gut (the ENS) and the nervous system that controls our release of stress hormones, the autonomic nervous system (the ANS) are linked finding ways to address the above symptoms will inevitably also improve that initial instigating mental health issue: the chronic stress and anxiety.

What can one do to address gut problems that are caused by stress and anxiety?

  • Drink lots of water, this is because water can help boost digestion.

  • Omega-3 foods such as nuts, seeds, and salmon.

  • Try incorporating some fermented probiotics a go such as kimchi, kombucha, or kefir into your diet.

  • Try to eat when you're calm and relaxed, this can help digestion and your body will absorb more of the important nutrients, vitamins, and minerals.

  • Vitamin D is a great source to help regulate your microbiome.

Self-care strategies for anxiety:

  • Be Mindful of Your Breathing

When we experience anxiety, our heart rate often increases. Deep breathing exercises help relax tense muscles, balance your breathing, and help regulate your heart rate. Look up the square breathing technique and follow along with the instructions.

  • Connect With Nature

Nature has a way of grounding us. The fresh air, the trees, the sound of a stream running, and the sense of freedom, we experience while hiking or camping- these can all help reduce anxiety and make us feel more connected to the world around us.

  • Engage Your Senses

One of the best ways to relax is to engage your senses. Using the 5-4-3-2-1 grounding technique can help alleviate anxiety. Name 5 things you can see, 4 things you can touch, 3 sounds you can hear, 2 things you can smell, and 1 flavour you can taste.

  • Eat Nutrient-Dense Food

Eat food like spinach, kale, and sweet potato which helps boost GABA production. GABA is a neurotransmitter that helps regulate anxiety.

  • Use Muscle Relaxation Techniques

Practice PMR or Progressive Muscle Relaxation. The process involves tensing/tightening the muscles and letting the muscles relax after. Start from your forehead and work your way down to your toes.

  • Challenge Your Thoughts

When we become anxious, we often accept our thoughts without questioning them. However, if we question our thoughts, then we can verify if it's true or not.


The more stressed you are, the more likely It is that your gut will bother you. However: you can treat your anxiety through treating your digestion and you can treat your digestion through healing your anxiety.

​​This is one of the many reasons why people who say that anxiety is 'all in the mind' are so, so wrong. Anxiety can make your stomach feel like hell on Earth, and to fight it we have to look towards improving both body and mind. Too many people ignore one or the other!