What is the best treatment approach for a patient with an eating disorder and Irritable Bowel Syndrome (IBS)?

Treatment of Eating Disorders with Comorbid IBS

When an eating disorder coexists with IBS, prioritize management of the eating disorder over gastrointestinal symptoms when the eating disorder severity is high, and avoid restrictive dietary approaches that could exacerbate disordered eating behaviors. 1

Critical First Step: Screen and Assess Eating Disorder Severity

• Routine screening for disordered eating or eating disorders is critical because they are common and often overlooked in gastrointestinal conditions. 1
• Conduct a careful dietary history to identify detrimental eating behaviors and beliefs, including assessment for food avoidance patterns, unintentional weight loss ≥5% in the previous 6 months, or avoidance of multiple food groups. 1
• Patients with eating disorders are poor candidates for restrictive diet interventions such as the low-FODMAP diet, which is otherwise first-line for IBS. 1

Treatment Algorithm Based on Eating Disorder Severity

High Severity Eating Disorder (Primary Focus)

When eating pathology is central or severe, prioritize eating disorder management over IBS symptom control. 1

• Refer immediately to a specialist eating disorder dietitian who can address both conditions simultaneously. 1

• Implement evidence-based eating disorder treatment:

  • Cognitive Behavioral Therapy-Enhanced (CBT-E) is the first-line psychological treatment for eating disorders and should be initiated. 2
  • Interpersonal Psychotherapy (IPT) is an alternative evidence-based option, particularly for patients with interpersonal difficulties. 2
  • Dialectical Behavior Therapy adapted for eating disorders (DBT-BED) can address emotion regulation and distress tolerance, which overlap with IBS symptom triggers. 2

• Avoid all restrictive dietary approaches for IBS during this phase, as they can worsen eating disorder psychopathology. 1

Moderate Eating Disorder with Moderate IBS (Integrated Approach)

Tailor interventions to include strategies for both conditions while avoiding restrictive approaches. 1

• Work with a gastroenterology dietitian who has expertise in eating disorders to provide:

  • Standard dietary advice for IBS (modification of fiber intake, restriction of caffeine and alcohol) rather than restrictive diets. 1
  • Soluble fiber supplementation (3-4g/day, gradually increasing) for IBS symptoms without triggering eating disorder behaviors. 1

• Implement psychological interventions that address both conditions:

  • Brain-gut behavioral therapies (BGBTs) such as gut-directed hypnotherapy or mindfulness-based approaches can improve IBS symptoms without exacerbating eating pathology. 1
  • CBT protocols that address both gut-brain axis dysregulation and eating disorder cognitions. 1

• Consider pharmacological management for IBS symptoms:

  • Antispasmodics for abdominal pain (avoiding weight-affecting medications when possible). 1
  • Low-dose tricyclic antidepressants (10-30mg) can address both IBS pain and comorbid depression/anxiety common in eating disorders. 1

Mild/Resolved Eating Disorder with Persistent IBS (Sequential Approach)

Once eating disorder behaviors are stable and nutritional status is adequate:

• Introduce standard dietary advice for IBS as first-line treatment. 1
• The low-FODMAP diet may be considered only after eating disorder stability is confirmed, delivered in three phases (restriction for 4-6 weeks maximum, reintroduction, personalization) under specialist dietitian supervision. 1
• Continue monitoring for re-emergence of eating disorder behaviors during any dietary modification. 1

Essential Multidisciplinary Coordination

Detail established eating disorder comorbidity on all referrals to other clinicians, as this influences treatment goals and dietary/psychological priorities. 1

• Coordinate care between eating disorder specialists, gastroenterologists, and mental health providers. 1
• Screen for additional comorbidities common in both conditions:
  • Depression and anxiety (which have bidirectional relationships with both eating disorders and IBS). 1
  • Nutritional deficiencies (vitamin D, folate, zinc). 1
  • History of trauma, which affects symptom perception and treatment response. 1

Pharmacological Considerations

• Avoid medications that significantly affect appetite or weight when possible in patients with active eating disorders. 1
• For IBS-specific symptoms:
  • Antispasmodics are generally safe and do not affect eating behaviors. 1
  • Low-dose TCAs provide dual benefit for IBS pain and comorbid mood symptoms without promoting weight gain at these doses. 1
  • Avoid laxatives or medications that could be misused for weight control. 1

Critical Pitfalls to Avoid

• Never implement the low-FODMAP diet or other restrictive dietary interventions in patients with active eating disorders or high eating disorder psychopathology. 1
• Do not focus solely on IBS symptom reduction while neglecting eating disorder severity, as this can worsen overall morbidity and mortality. 1
• Avoid multiple food group restrictions that could trigger or worsen nutritional deficiencies already common in eating disorders. 1
• Do not dismiss food-related anxiety as purely IBS-related without screening for underlying eating pathology. 1
• Ensure any dietary intervention includes strategies to prevent development or worsening of disordered eating patterns. 1

Monitoring and Reassessment

• Assess both gastrointestinal and psychological symptoms at each visit to evaluate treatment response in both domains. 1
• Monitor for signs of eating disorder relapse during any dietary modification: increased food restriction beyond prescribed diet, weight loss, increased body image concerns, or rigid food rules. 1
• Adjust treatment priorities based on which condition is causing greater impairment in quality of life and functioning. 1