Anxiety and Stomach and Gut Symptoms: How the Brain-Gut Axis Works

Can anxiety cause stomach pain, nausea and gut problems? Learn about the brain-gut axis, the symptoms, exercises you can try and the therapy process.

Do butterflies flutter in your stomach before an important presentation, does breakfast not go down on the morning of an exam, or do you often need the toilet on the way to a job interview? Our idioms, such as "my stomach is tied in knots", "I can't stomach it" and "my stomach is scraped raw", are not there for nothing. Anxiety is an emotion that can directly affect the stomach and gut, and this effect is often far stronger than people think. Some people go back and forth to gastroenterology clinics for years, hearing that their tests are clear while their complaints continue. In this article we explain in detail how communication between the brain and gut works, the ways in which anxiety affects the digestive system, techniques you can apply yourself and the place of therapy in the process.

What Is the Brain-Gut Axis?

The digestive system is not just a tube that processes what we eat. In the walls of the gut there is a large network of nerves that scientists also call the "second brain". This network is called the enteric nervous system. The enteric nervous system is complex enough to run digestion independently of the brain, but it is also in constant communication with the brain.

This communication is two-way and takes place over several different channels:

• The vagus nerve: One of the most important highways between brain and gut. A significant part of the information actually flows from the gut to the brain.
• Stress hormones: Stress hormones released during anxiety can affect gut movement, stomach acid secretion and gut permeability.
• The immune system: The gut is a region where immune cells are found in large numbers. Long-term stress can change the delicate balance in this region.
• The gut microbiota: The relationship between the microorganisms living in the gut and mood has been intensively researched in recent years. Although findings in this area are promising, many questions are still waiting for answers; definite claims such as "this probiotic cures anxiety" should therefore be treated with caution.

Thanks to this axis, an alarm in the brain can be felt in the stomach within seconds; conversely, a disturbance in the gut can also affect mood.

Can Anxiety Cause Nausea and Stomach Pain?

Yes, it can. Anxiety can lead to symptoms such as nausea, cramps and indigestion. To understand this, we need to look at the evolutionary function of anxiety. When the brain perceives danger, it starts the "fight or flight" response. In this response the body directs its energy to the systems most needed for survival, that is, the muscles, heart and lungs. Digestion is not a priority at that moment. For this reason:

1. Blood flow to the stomach falls. Digestion slows, and a feeling of fullness and nausea can appear.
2. The stomach muscles tense. A feeling of a "knot in the stomach" or cramp can form.
3. Gut movements change. In some people they speed up and lead to diarrhoea, in others they slow down and lead to constipation.
4. The perception of pain increases. Anxiety can cause normal signals from the gut to be perceived as more intense and uncomfortable. This is called visceral hypersensitivity.

For a short-lived danger this response is extremely functional. The problem begins when anxiety becomes chronic. When the body stays in a state of constant alarm, the digestive system too keeps carrying this heavy load.

Common digestive symptoms linked to anxiety

• Nausea, a feeling of retching
• Heartburn, indigestion, bloating
• Abdominal pain and cramps
• Sudden urgency to use the toilet, diarrhoea or constipation
• Loss of appetite or, conversely, a craving to overeat at moments of stress
• A lump in the throat, difficulty swallowing

Anxiety is not the only cause of stomach complaints; many of these symptoms can also be seen in physical illnesses. It is therefore very important not to brush off your digestive complaints with "it's only anxiety" but to have them assessed by a doctor first. For other bodily faces of anxiety you can also look at our article on anxiety symptoms.

The Relationship Between Anxiety and Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) is a common condition linked to brain-gut interaction, marked by abdominal pain and changes in bowel habits. It is diagnosed by a doctor. A strong relationship between IBS and anxiety is a well-known finding in the field. This relationship runs both ways: anxiety can increase symptoms, and symptoms can increase anxiety.

Say a teacher has sudden abdominal pain a few times during lessons and has trouble reaching the toilet in time. After a while they begin to worry in the mornings on the way to school: "What if it happens again?" This worry raises gut sensitivity even further. They skip breakfast, memorise the toilets along the route, and sit near the door in meetings. Although these behaviours give reassurance in the short term, in the long term they narrow their life and contribute to feeding the anxiety.

In this picture, running medical treatment and psychological support together is often the most balanced approach. If you would like to read in a wider frame about how bodily symptoms and psychological processes are intertwined, our article on psychosomatic symptoms may be a guide.

Everyday Sources of Stress That Affect the Stomach and Gut

Developments in Turkey in recent years have raised many people's stress levels for good. Worry about making ends meet because of the cost of living, rent increases, job insecurity and long, tiring commutes within the city also show up in the digestive system. Lunches eaten standing, in a hurry and in front of a screen, skipped meals, tea and coffee drunk one after another all day, and heavy late dinners all worsen the picture.

The effect of digital life should not be ignored either. Looking at the news feed during a meal, answering work emails or scrolling social media makes it harder for the body to switch to its "rest and digest" mode. Digestion works more easily when the parasympathetic nervous system, the body's calming system, is active. When the mind is on alert, the stomach stays on alert too.

Among students, stomach pain, nausea and loss of appetite are common complaints during the LGS and YKS periods (Turkey's national high-school and university entrance exams). In children, the sentence "My tummy hurts" can sometimes be the bodily language of anxiety about going to school, separation anxiety or tension at home.

What Can Be Done When Anxiety Causes Nausea and Stomach Pain?

When anxiety is putting a strain on your stomach and gut, the techniques below can be applied after a doctor's assessment and in addition to your medical treatment. None of them is a treatment on its own, but when practised regularly they can help calm your body's alarm system.

1. Diaphragmatic breathing: activating the vagus nerve

Slow, deep belly breathing supports the body's calming system by increasing the activity of the vagus nerve. Put one hand on your chest and the other on your belly. Breathe in through your nose for four seconds; make sure the hand on your chest stays still and the hand on your belly rises. Breathe out slowly for six seconds. It is important that the out-breath is longer than the in-breath. Practise for five minutes twice a day, and also a few cycles before every meal.

2. A "transition pause" before meals

Before you sit down at the table, stop for a minute. Turn your phone face down or leave it in another room. Take three slow breaths. Look at the colour of the food in front of you and smell it. This short pause gives your body the message "There is no danger now, you can digest." Staying away from screens during meals also makes it easier to notice how much you are eating.

3. Keep a symptom diary

For two weeks, write your stomach and gut complaints in a notebook: when did it start, what were you doing at that moment, what was going through your mind, what had you eaten, what was your anxiety from 0 to 10? These records often reveal surprising patterns. For example, you may notice that the complaints increase on Sunday evenings, before meeting a particular person or on bill-paying days. This diary becomes a valuable source of information you can share with your doctor and therapist.

4. Progressive muscle relaxation

Sit in a comfortable position. Starting from your feet, work by tensing each muscle group for five seconds and then releasing it for ten: feet, calves, thighs, abdomen, hands, arms, shoulders, face. When you tense and release the abdominal muscles in particular, try to notice the difference between tension and looseness. Many people discover with this exercise that they have been clenching their belly all day without realising.

5. Catch catastrophic thoughts

When nausea begins, notice the thoughts passing through your mind: "I'm going to be sick", "If I can't get to the toilet I'll be humiliated", "I definitely have something serious." Ask these thoughts these questions: "How many times has this feeling come before and what happened in the end? What is the evidence for this thought? What would I say to a friend going through this?" Changing the thought does not remove the bodily sensation at once, but it eases the second layer of anxiety added to the sensation.

6. Move

Regular walking can help regulate gut movement and balance stress hormones. Even a light 10 to 15 minute walk after a meal can have a positive effect on both digestion and mood.

7. Reduce safety behaviours one by one

Many people with anxiety-related stomach complaints, without realising it, arrange their lives around their symptoms: not eating at all before a journey, always carrying stomach medication in their bag, going only to places where the toilet is known, choosing the seat nearest the door in meetings. These behaviours reassure in the short term, but they give the brain the message "this situation really is dangerous" again and again. This week, choose just one of these behaviours and loosen it with a small step. For example, set off on a short bus journey after a light breakfast, or sit a little away from the door. Observe the anxiety rising and then falling on its own. Write the result in your symptom diary. These small experiments help you see that your body is more resilient than you thought.

The stomach often hears the voice of the mind before we do; instead of silencing it, trying to understand what it says is the beginning of healing.

When Should You Seek Professional Support?

If your digestive symptoms have just begun, are severe, or are accompanied by signs such as weight loss, bleeding, pain that wakes you at night, fever, difficulty swallowing or vomiting, you need to see a doctor without delay. Once physical causes have been assessed, you may consider psychological support in these situations:

• If your complaints continue even though your tests are clear
• If symptoms clearly increase in stressful periods
• If you avoid going out, travelling or attending meetings because of a fear of not reaching the toilet or of vomiting
• If you constantly research your symptoms and worry that you have a serious illness
• If anxiety affects your sleep, work and relationships

If anxiety is at a level that requires medication, a psychiatrist makes this assessment. Psychotherapy support in the area of anxiety and panic can be carried out face to face or online.

How Are Anxiety-Related Stomach and Gut Problems Approached in Therapy?

Cognitive Behavioural Therapy (CBT) is one of the approaches often used for anxiety-related digestive complaints. In therapy the process usually includes these components:

Psychoeducation: How the brain-gut axis works, how anxiety amplifies bodily sensations and how avoidance keeps the cycle going are made understandable. This knowledge makes it easier for the person to look at their body with understanding rather than hostility.

Cognitive work: Catastrophic interpretations of bodily sensations, health anxieties and beliefs such as "If I lose control I'll be humiliated" are examined.

Behavioural work: Avoidance of places without toilets, certain foods, journeys or social settings is gradually reduced. Safety behaviours such as constantly checking where the toilet is, researching symptoms and seeking reassurance are reviewed together.

Relaxation and attention work: Breathing, muscle relaxation and exercises for widening attention beyond the body are learned in sessions and carried into daily life.

Work on origins: If deep beliefs such as "I must control everything" and "I mustn't show weakness" lie beneath the anxiety, these beliefs can be addressed with a schema-focused view.

This process does not conflict with the treatment your doctor recommends; on the contrary, it complements it. The ideal is for medical and psychological support to go forward in knowledge of each other.

Frequently Asked Questions

Does anxiety cause stomach pain, or am I imagining all this?

Anxiety leads to real bodily changes; the pain or nausea you feel is not imaginary. Stress hormones, muscle tension and changes in gut movement can create concrete symptoms. Even so, it is important to see a doctor first to rule out physical causes.

How long does anxiety-related nausea last?

In a brief moment of anxiety, nausea usually eases once the trigger has gone. In chronic anxiety, symptoms may last longer and recur. Regular breathing work, sleep and eating routines, and addressing the anxiety itself can ease this.

Do probiotics reduce anxiety?

Research on the relationship between the gut microbiota and mood is continuing and has not yet reached the level of making firm recommendations. You should always consult your doctor before using any supplement.

My child often complains of tummy ache. Could it be anxiety?

It could; children often express their feelings through their bodies. But a paediatrician's assessment should be done first. If no physical cause is found, it may help to observe when the pain increases and to see a child mental health specialist.

• #brain-gut axis
• #anxiety
• #irritable bowel
• #stress

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Eda Erkan Alapala

Klinik Psikolog. İstanbul Kent Üniversitesi Klinik Psikoloji Tezli Yüksek Lisans mezunu; bilişsel davranışçı terapi, çocuk merkezli oyun terapisi ve çocuk-ergen psikoterapisi alanlarında eğitimlerini tamamlamıştır.

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