The Gut-brain axis is the bidirectional communication between the central (brain) and the enteric (gut) nervous systems. The brain contains the most nerve cells in the body. The digestive tract, with the next most abundant nerve network, is sometimes referred to as the ‘Little Brain’.
The digestive tract and the brain have an extensive and complex, two-way communication. Have you ever had a gut feeling? Trusted your gut? Our thoughts, emotions, stress and other psychological factors can affect gut sensation, motility, secretion, sensation etc. In the reverse, sensations arising in the gut can affect the brain or central nervous system affecting our mood, behaviour and/or feelings of pain, even the quality of our sleep!
In an individual with normal gut function, the gut-brain axis works away in the background to regulate digestions and movement of food without us noticing. Sometimes, these signals between the gut and the brain can become scrambled or misinterpreted such as the case with sufferers of Irritable Bowel Syndrome (IBS).
Irritable Bowel Syndrome (IBS)
In IBS, there seems to be an abnormal reception by the brain of the signals from the gut. As well as an increased responsiveness in the gut of the signals received from the brain. I often describe this to clients is that they have ‘hyperactive’ nerve endings in their gut that are more likely to react to the following main offenders;
- Stimulating meals, such as FODMAP containing foods or meals with spice, heat or high amounts of fat
- The pace at which they eat
- The amount of air they breath in when eating
- Volume of food (the bigger the meal the more likely to have symptoms)
- Stress and other negative feelings.
Some statistics suggest half of IBS sufferers also suffer from depression or anxiety which in turn exacerbates the gut symptoms which makes them more stressed and the wheel just keeps on turning.
The brain said to the gut…
I often have clients discuss various gut symptoms they experience when they are nervous; a stint of public speaking make bring on a mad dash to the bathroom, nerves for an upcoming race may result in every meal ending in a world of bloat. It’s not just feelings of nervousness that can increase the sensitivity of the gut, other ‘stressors’ such as extreme physical exertion, emotions such as sadness, guilt, anger, work stress, family stress, anxiety, depression, the list goes on.
The gut said to the brain….
I make a point to discuss with clients their day-to-day mood, particularly if they are reporting fairly poor nutritional intake. Given the research that has demonstrated the high degree of communication going back and forth between the gut, if you were only putting in foods that were nutritionally inadequate, the breakdown of those foods will be impacting the signals the brain receives, who in turn, will not be putting out ‘positive vibes’. Two human studies that looked at people who suffered from major depression showed the bacteria in their stool samples differed from healthy volunteers. Perhaps even more astounding, in a study last year gut microbiota samples from people with major depression were used to colonise bacteria-free rats. These rats went on to show behavioural changes related to depression. The research is still emerging and we are still yet to understand what ‘normal’ bacteria is but it provides further reason to ensure the nutritional quality of your food is enough to nourish your body as well as your brain.
If you suffer from IBS or other gut related symptoms, don’t suffer in silence – see your dietitian.