Gut Disorders and Eating Disorders Are Deeply Linked, and Anxiety May Be the Bridge

For clinicians treating irritable bowel syndrome or functional dyspepsia, the presence of an eating disorder in the same patient is not unusual. What has been harder to establish is which condition tends to come first, and whether psychological factors like anxiety and depression are driving the sequence. A new retrospective cohort study published in Clinical and Translational Gastroenterology by Egboh SC and colleagues offers some of the clearest evidence yet, drawing on records from more than 1.25 million patients in UK general practices.

Eating Disorders and Gut-Brain Disorders Overlap at Striking Rates

Among the 1,256,331 patients in the dataset, 1,018 carried diagnoses of both a disorder of gut-brain interaction (DGBI) and an eating disorder. DGBIs are a broad category that includes conditions like irritable bowel syndrome (IBS), functional dyspepsia (FD), and chronic constipation, all characterized by persistent gastrointestinal symptoms without a clear structural cause. Eating disorders include anorexia nervosa, bulimia nervosa, and binge eating disorder, among others. The overall prevalence of any eating disorder in the cohort was 0.7%, but within that overlap group, the associations between specific conditions were striking. Research tracking high DGBI prevalence in eating disorder patients has previously found that up to 95% of people with eating disorders report at least one DGBI, underlining how consistently these two categories travel together.

In this study, IBS and functional dyspepsia both showed significant associations with one or more eating disorders. Chronic constipation stood out particularly: it was associated with anorexia nervosa at an odds ratio of 2.12 (95% CI 1.84 to 2.45) and with any eating disorder at an odds ratio of 2.06 (95% CI 1.79 to 2.36). An odds ratio above 2.0 was the threshold the researchers set for clinical significance, which both figures cleared.

Which Condition Comes First Matters for Treatment

The study's most clinically useful contribution is its attempt to establish chronological order. In 59.5% of the 1,018 patients, an eating disorder diagnosis came before the DGBI diagnosis. In the remaining 40.5%, the DGBI appeared first. That difference was statistically significant (P<0.001), and it has real implications: if clinicians know that gut symptoms often follow rather than precede an eating disorder, screening for disordered eating in patients presenting with new-onset IBS or constipation becomes more defensible.

But the direction can also run the other way, and the study identified three independent predictors for DGBI preceding an eating disorder: younger age at first DGBI diagnosis (P<0.001), antecedent depression (P=0.003), and prior proton pump inhibitor (PPI) use (P<0.001). The PPI finding is intriguing. PPIs suppress stomach acid and are prescribed for conditions like reflux and functional dyspepsia; their appearance as a predictor may reflect the severity of gut symptoms, or potentially gut microbiome disruption, though the study does not establish causation.

How the Gut-Brain Axis Connects Both Disorders

The biological scaffolding linking these conditions is the gut-brain axis, a bidirectional communication network involving neural, hormonal, and immune pathways between the gastrointestinal tract and the central nervous system. Anxiety and depression are not merely bystanders in this system. Among the 777 patients in the study who also had anxiety and/or depression data, psychological comorbidity shaped the sequence of diagnoses in measurable ways. Antecedent depression, in particular, emerged as an independent predictor of gut symptoms arriving before the eating disorder.

Emerging work on gut microbiota's role in anorexia and depression suggests that gut dysbiosis, an imbalance in the microbial community of the intestine, is associated with increased anxiety, depressive symptoms, and disordered eating behaviors. This points toward a plausible biological mechanism: altered gut flora could amplify psychological distress, which in turn lowers the threshold for both gut-motility problems and restrictive or compulsive eating patterns. Similarly, research into gut-brain axis disruption in binge eating implicates dysbiosis and dysfunctional central circuitry as contributing factors in that disorder's pathology.

Limitations of a Retrospective Cohort Design

The study's size is its greatest strength; 1.25 million records drawn from UK primary care represent a real-world population rarely captured in clinical trials. But retrospective cohort designs carry inherent constraints. Diagnosis dates in general practice records reflect when a clinician coded a condition, not necessarily when symptoms began. A patient may have had subclinical gut symptoms for years before a formal IBS diagnosis, which could shift the apparent chronology. The subset with anxiety and depression data was smaller at 777 patients, limiting the statistical power for those specific analyses. The study also does not fully account for confounders like socioeconomic status, medication history beyond PPIs, or specific eating disorder subtype in all analyses.

Because this is observational research, the associations it identifies cannot confirm that one condition causes the other. The findings are consistent with a shared vulnerability model, in which psychological distress, gut dysfunction, and disordered eating all amplify one another, but the causal arrows remain uncertain.

What Comes Next for Screening and Treatment

The practical implication the authors point toward is improved cross-disciplinary screening. Gastroenterologists managing IBS or functional dyspepsia patients, particularly younger ones with comorbid depression, may benefit from routine eating disorder assessments. Equally, eating disorder treatment teams might consider DGBI screening as a standard part of intake.

Therapeutic possibilities remain speculative but are attracting attention. Microbiota-targeted interventions, sometimes called psychobiotics, are being explored as a way to modulate the gut-brain axis in conditions like binge eating disorder, though this research is still early. For now, the most actionable takeaway from this study is structural: the gut and the mind rarely malfunction in isolation, and the sequence in which symptoms emerge may tell clinicians something important about where to intervene first.

Evidence rating

EMERGING — 76/100

Caveats:

• Retrospective observational design — shows associations, not causation; unmeasured confounders are likely.
• Only 1,018 patients had both diagnoses out of 1.25 million, limiting generalisability to people with co-occurring conditions.
• Diagnosis timing relies on GP records, which may not reflect true onset of symptoms.
• Funding was not disclosed by the authors, so independent verification of the funding source is not possible.
• Findings have not yet been independently replicated in a separate cohort.

Large retrospective cohort study drawing on 1,256,331 UK general practice records, with 1,018 patients carrying both a gut-brain disorder and an eating disorder diagnosis. The design establishes associations and chronological ordering but cannot determine causation, and findings rely on the completeness and accuracy of routine clinical records. The study has not yet been independently replicated.

References

1. SC Egboh, NA Koloski, MP Jones, A Shah, G Holtmann, NJ Talley (2026). ROLE OF ANXIETY AND DEPRESSION ON THE INTERPLAY BETWEEN DISORDERS OF GUT-BRAIN INTERACTION AND EATING DISORDERS. Clinical and Translational Gastroenterology. https://doi.org/10.14309/ctg.0000000000001025
2. Camilla A. Wiklund, Marianna Rania, Ralf Kuja‐Halkola, Laura M. Thornton, Cynthia M. Bulik (2021). Evaluating disorders of gut‐brain interaction in eating disorders. International Journal of Eating Disorders. https://doi.org/10.1002/eat.23527
3. Fatima Shahid, Zain Afridi, Muhammad Ali, Muhammad Nabeel Saddique, Javed Iqbal, Anurag Jha (2025). Beneath the surface: unveiling the gut–brain axis in anorexia and depression. Eating and Weight Disorders – Studies on Anorexia, Bulimia and Obesity. https://doi.org/10.1007/s40519-025-01719-2
4. Weiwei Guo, Wei Xiong (2024). From gut microbiota to brain: implications on binge eating disorders. Gut Microbes. https://doi.org/10.1080/19490976.2024.2357177
5. Elizabeth Schneider, Sarah-Jane Leigh, Caoimhe M.K. Lynch, et al. (2024). Microbiota-gut-brain axis in binge-eating disorder: Towards microbiome-based therapies. Neuroscience Applied. https://doi.org/10.1016/j.nsa.2024.104088