What dietary approach is recommended for managing Inflammatory Bowel Syndrome (IBS)?

Dietary Management for Irritable Bowel Syndrome (IBS)

The low FODMAP diet, implemented as a three-phase process and supervised by a registered dietitian, is the most effective dietary approach for managing symptoms in patients with Irritable Bowel Syndrome. 1

First-Line Dietary Recommendations

• All patients with IBS should be advised to follow traditional first-line dietary advice before considering more restrictive diets 2:

  • Maintain regular meal patterns and avoid skipping meals 3
  • Take time to eat meals in a relaxed environment 3
  • Drink at least 8 glasses of fluid daily, primarily water 3
  • Limit caffeine intake to 3 cups of tea/coffee per day 3
  • Reduce alcohol and carbonated beverage consumption 3
  • Limit fresh fruit to 3 portions daily (80g per portion) 3

• Regular exercise should be recommended to all IBS patients as it can help manage symptoms 2, 3

• Soluble fiber supplementation (e.g., ispaghula/psyllium) is effective for global symptoms and abdominal pain in IBS 2, 3:

  • Start with low doses (3-4g/day) and gradually increase to avoid bloating 2
  • Target total daily intake of 20-30g/day 2

• Insoluble fiber (e.g., wheat bran) should be avoided as it may exacerbate abdominal pain and bloating 2, 3

• Probiotics may be effective for global symptoms and abdominal pain in IBS 2:

  • Recommend a 12-week trial period and discontinue if no improvement occurs 2
  • No specific species or strain can be recommended over others 2

Second-Line Dietary Approach: Low FODMAP Diet

• The low FODMAP diet should be implemented when first-line dietary advice is insufficient 2, 1

• Implementation should follow a structured three-phase process 1:

  1. Restriction phase (4-6 weeks): Substantially reduce all FODMAP intake 1
  2. Reintroduction phase (6-10 weeks): Systematically challenge with foods containing single FODMAPs to identify triggers 1
  3. Personalization phase: Long-term diet based on individual tolerances 1

• Most patients report symptom improvement within 2-6 weeks of starting the restriction phase 1

• Multiple randomized controlled trials demonstrate the effectiveness of low FODMAP diet for IBS symptoms 4, 5, 6:

  • Significantly reduces overall gastrointestinal symptoms compared to regular diet 4, 6
  • Improves stool consistency and frequency, particularly in diarrhea-predominant IBS 4
  • Approximately 70% of patients respond to the diet with symptom improvement 1

• Common FODMAP triggers include fructans, mannitol, and galacto-oligosaccharides, with wheat, milk, and garlic being frequent culprits 1

Important Considerations and Potential Pitfalls

• Referral to a registered dietitian with gastrointestinal expertise is strongly recommended for implementing the low FODMAP diet 1

• The low FODMAP diet should not be continued indefinitely in its strictest form as it may negatively impact the intestinal microbiome, particularly reducing beneficial bifidobacteria 1

• Food elimination diets based on IgG antibodies are not recommended for IBS management 2

• A gluten-free diet is not recommended for IBS unless celiac disease or non-celiac gluten sensitivity is confirmed 2

• For patients with comorbid mental health conditions, consider a gentler approach focusing on selected high-FODMAP foods rather than complete restriction 1

• A simplified approach targeting only specific FODMAP subgroups (particularly fructans and galacto-oligosaccharides) may be effective and less restrictive 7

Alternative Dietary Approaches

• The Mediterranean diet shows benefit for some IBS patients and may be appropriate for those with milder symptoms 1

• For patients with diarrhea-predominant IBS, loperamide may be effective but should be carefully titrated to avoid side effects like constipation 2, 3

• Certain antispasmodics may effectively treat global symptoms and abdominal pain in IBS 2, 3

• Low-dose tricyclic antidepressants (starting at 10mg amitriptyline) can be effective as second-line treatment for global symptoms and abdominal pain 3