The brain-gut axis and Coeliac disease

What is the brain-gut axis?

The digestive tract is packed with 100+ million nerve cells –so many that the it is often referred to as the second brain. This system, called the enteric nervous system, extends from the oesophagus, through the stomach, small bowel, large bowel, and ends at the anus.

The enteric nervous system has a special bi-directional relationship with the brain (i.e. the central nervous system), often referred to as the brain-gut or gut-brain axis. As your digestive tract is performing its usual function of digesting food, the enteric nervous system is relaying information back to the brain. These signals relate to various kinetic, microbiological, and immune processes occurring throughout the digestive tract and are suggested to have a significant impact on our thoughts, feelings, and behaviours.

Feelings of gut discomfort that arise in the gut (e.g. pain, cramping), can instil feelings of anxiety or worry, which can cause increase the speed at which the intestines contract and move food through the digestive system, resulting in further gastrointestinal symptoms and discomfort (e.g. diarrhoea). Similarly, psychological stress can alter the balance of gut microbiota (i.e. the trillions of microorganisms that inhabit the gastrointestinal tract), which can alter digestive function/symptoms and has been associated with various psychological disorders (e.g. anxiety, depression).

Our current understanding of the brain-gut axis also suggests that inflammation in the gastrointestinal tract can exacerbate symptoms of psychological distress. Given that active coeliac disease causes inflammation within the small bowel (alongside other kinetic, and biochemical changes), this may contribute to distress-inducing gut-to-brain signals. These signals are received by the brain and may manifest as various forms of psychological distress (e.g. anxiety, stress, low mood). These states of psychological distress are in turn associated with poorer dietary management (i.e. higher likelihood of gluten exposure), thus potentially perpetuating small bowel inflammation, and creating a cycle of sorts between ill psychological health and the damaged/inflamed small bowel.

The brain-gut axis is a complex interplay between a multitude of processes and its role in coeliac disease is not yet fully understood. Nonetheless, existing research strongly supports the interrelationship between the health and function of the gut and one’s psychological well-being.