Eating disorders and Irritable Bowel Syndrome (IBS) are complex conditions that often intersect. This article explores the connection between eating disorders and IBS, highlighting how a specialist gut health dietitian can help you address your concerns.

What is IBS?

Irritable Bowel Syndrome (IBS) is a common gastrointestinal disorder characterised by symptoms such as abdominal pain, bloating, reflux, gas, and altered bowel habits, including diarrhoea, constipation, or a combination of both. IBS is a chronic condition with symptoms that can significantly impact daily life. Although the exact cause of IBS is not fully understood, factors like genetics, gut-brain axis dysfunction, food sensitivities, gut microbiome dysbiosis and psychological stress are widely considered to contribute. 

What Are Eating Disorders?

Eating disorders are serious mental health conditions that involve disordered eating behaviours and significant preoccupations with body weight, shape or eating itself. Common eating disorders include Anorexia Nervosa, Bulimia Nervosa, and Binge Eating Disorder, however there are many more. In the gut health space, we are seeing increasing numbers of individuals presenting with Avoidant/Restrictive Food Intake Disorder (ARFID). ARFID is characterised by avoidance, restriction or concern about certain foods and can often be the precursor as well as the result of managing IBS. In any case, all eating disorders can lead to severe physical health problems, including malnutrition, electrolyte imbalances, circulatory disorders and gastrointestinal issues, as well as psychological distress.

What’s the Link Between IBS and Eating Disorders?

1. Gut-Brain Axis Dysregulation: Both eating disorders and IBS involve dysregulation of the gut-brain axis, which is the bidirectional communication pathway between the gut and the brain. Have you ever felt “butterflies” in your stomach when you’re nervous, or have you ever had to run to the loo? These are clear examples of the gut-brain axis in action! Psychological stress, anxiety, and depression can exacerbate IBS symptoms, and are also significant factors in the development and maintenance of eating disorders.
2. Nutritional Deficiencies and Gut Health: Individuals with eating disorders often suffer from nutritional deficiencies that can negatively impact gut health. For example, in the simplest of cases, inadequate intake of fiber can lead to constipation. In others, inadequate fibre intake can lead to the gut microbiota feeding on the protective mucin layer of the gut wall. This inevitably leads to gut dysbiosis which we’ll explore further in a moment. 
3. Altered Gastrointestinal Motility: Disordered eating behaviors, such as severe food restriction, binge eating, and purging, can disrupt normal gastrointestinal motility. This disruption can lead to symptoms commonly seen in IBS, such as bloating, abdominal pain, and irregular bowel movements. In severe cases, this can also lead to other digestive conditions such as gastroparesis (delayed emptying of the gut). 
4. Psychological Stress and IBS: High levels of psychological stress, common in those with eating disorders, can trigger or worsen IBS symptoms. Stress can affect gut motility, increase gut sensitivity, and alter the gut microbiome, contributing to the severity of IBS and its impact on one’s quality of life. 
5. Gut Microbiome Imbalance: Eating disorders can lead to significant changes in the gut microbiome. We need to eat a variety of food to fuel the trillions of different bacteria in our gut. Food restriction results in scarcity of some bacteria, and an overabundance of others. This imbalance is commonly referred to as microbiome imbalance or gut dysbiosis. Dysbiosis has been found to be associated with both IBS and eating disorders. It can lead to increased gut permeability, inflammation, and altered gut function.

How can an expert dietitian help?

Addressing nutritional deficiencies and restoring a balanced diet is a crucial first step. As gut health and credentialed eating disorder dietitians, we can develop a personalised nutrition plan that meets your individual needs, supports gut health, and alleviates IBS symptoms. Most importantly, we will help promote a positive and healthy relationship with food, your body and eating. 

References

Almeida, M. N., Atkins, M., Garcia-Fischer, I., Weeks, I. E., Silvernale, C. J., Samad, A., Rao, F., Burton-Murray, H., & Staller, K. (2024). Gastrointestinal diagnoses in patients with eating disorders: A retrospective cohort study 2010-2020. Neurogastroenterology and motility, 36(6), e14782. https://doi.org/10.1111/nmo.14782

Harer K. N. (2019). Irritable Bowel Syndrome, Disordered Eating, and Eating Disorders. Gastroenterology & hepatology, 15(5), 280–282.

Tait, C., & Sayuk, G. S. (2021). The Brain-Gut-Microbiotal Axis: A framework for understanding functional GI illness and their therapeutic interventions. European journal of internal medicine, 84, 1–9. https://doi.org/10.1016/j.ejim.2020.12.023