IBS and the Gut-Brain axis


IBS and the Gut-Brain axis

Have you ever experienced being away on holiday and being able to eat just about anything with no issues, just to come home and have your gut go back to its old tricks? This is a super common scenario! And, it’s a really great example of how much impact the gut brain axis can have on Irritable Bowel Syndrome (IBS) symptoms.

IBS is now listed in medical guidelines as a disorder of the gut brain axis. This means that we know IBS symptoms are in a big part determined by the sensitivity of the nerves in the gut and how they communicate with the gut brain axis. Think of it like this, onion and garlic are actually FODMAPs for everyone because humans do not have the enzyme required to break down the FODMAPs they contain. This means no one is able to properly digest them and in everyone the FODMAPs will travel to the large intestine (or colon) and create large amounts of gas. This gas stretches the walls of the intestines and pushes on the nerves around them. In someone who doesn’t have IBS, the nerves mostly ignore this action. However, in someone who has sensitive nerves in their gut, this action can result in a huge amount of pain.

In this article, we are going to talk about:

  • What is IBS
  • What is the gut brain axis
  • How pain is produced in the body including in the gut
  • How stress impacts the gut brain axis
  • Strategies you can use to improve the functioning of your gut brain axis

What is IBS?

IBS is what we call a “functional condition”. What this means is that a person is living with a group of symptoms that don’t have an identifiable physical cause In the case of IBS, we know that the nerves in and around the gut appear to be more sensitive than someone without IBS. It’s the behaviour of these nerves that may result in painful or embarrassing symptoms.

What is the gut brain axis?

Our gut brain axis (or vagus nerve) is an integral part of our nervous system. It’s a two-way superhighway that carries information between the gut and the brain. Information travels from the brain to the gut about how sensitive to be, how fast to move. Information also travels in the other direction from the gut to the brain about what is happening down there.

Pain and the gut brain axis

To understand the gut brain axis and how it impacts IBS, it’s good to start with a basic explanation of how pain is produced. To start with, all pain is generated by the head brain. Our five senses (sight, smell, touch etc) collect information about our outside world and send this information to our brain. The brain then considers this information against past experience, current situation and future expectations. If it determines that there is something wrong or dangerous, it will send pain as an alarm bell to get your attention and get you to change what you are doing. For example, if we touch a hot element the heat sensation goes to the brain, the brain recognises that if we leave our finger there it will get burnt, so it sends pain to get us to move our finger, thus preventing a burn.

Now, the nerves in and around the gut act in the same way. They collect information about our inside world and send that to our brain via the gut brain axis. In the case of IBS, the nerves in the gut tend to be oversensitive and “over collect” information which they then “over communicate” with the brain. Additionally, it is thought that some of this information gets scrambled by the gut brain axis, making the brain concerned that there is something dangerous going on down there. Thus, pain and discomfort is sent as a response. Over time, the nervous system begins to recognise these messages more and more and respond more quickly to the information provided by the gut nerves. This can evolve to create an IBS cycle where IBS causes stress and then stress causes IBS.

Stress & IBS

If you’ve had IBS for some time, you will know that stress can also play a role and can cause IBS type symptoms. For some symptoms can occur even when they are eating a low FODMAP diet due to stress activating the nervous system and increasing the communication between the brain-gut axis. If you’re stressed, under pressure or even just experiencing typical low level chronic stressors of work, family and life, then this can be enough to keep you in fight or flight mode. Being in fight or flight mode means all nerves in your body on high alert for imminent danger, like a sabre toothed tiger, including those in your gut. If you can move out of the flight or flight mode and are feeling calm and relaxed, then all the nerves in your body will be more relaxed, including those in the gut, making them less likely to misbehave.



What can you do to calm the brain-gut axis?

The cool thing is about our body is that our nervous system is not hard wired like the electrics in a house. We have this thing called neuroplasticity, which means our nerves can grow and learn. Just like they can learn to be sensitive, they can also learn to be less sensitive. Here are some strategies that you can use to calm your gut-brain axis and hopefully this give you more room to move with food without triggering symptoms:

  • Gut directed hypnotherapy on its own has been proven in research to be as effective as a low FODMAP diet at reducing IBS! You can read more about hypnotherapy and the research behind it for IBS here.
  • Cognitive behavioural therapy (CBT). CBT works on how changing how you think about your symptoms, which helps you and your gut feel more calm, resulting in fewer and less distressing symptoms.
  • Mindfulness, meditation and deep breathing. It’s easy to fall into a cycle of feeling anxious because you have symptoms and them the anxiety causing symptoms, making it a chicken or the egg situation. Mindfulness, meditation and deep breathing can break this cycle, calming and relaxing your nervous system.
  • Yoga and light exercise. Stretching and light exercise are great for digestion, great for the soul and great for calming an overactive nervous system.
  • Activities that bring you joy. It really doesn’t matter what you do, but including something that brings you joy each day lifts your mood, reduces stress and improves your quality of life. Over time feeling better about life, reduces stress and calms the gut-brain axis.

Final thoughts

Your mental health and your physical health are strongly intertwined and if you have a stressed brain, you may also have a stressed gut. The good news is that by calming the head brain, you can also calm the gut-brain and improve your IBS significantly. So if needed a go ahead to include some time each day doing something purely for pleasure and work on techniques to improve how your body handles stress.

If you’ve never meditated or think you’re not very good at it, this short You Tube clip is for you.





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Meet Joanna


Joanna is a passionate advocate, communicator and educator in the fields of gut health, nutrition and wellness.