What supplements are recommended for post-infectious Irritable Bowel Syndrome (IBS)?

Supplements for Post-Infectious IBS

Glutamine supplementation (5g three times daily) is the most strongly recommended supplement for post-infectious IBS, demonstrating dramatic symptom improvement in 80% of patients with intestinal hyperpermeability. 1

Primary Recommendation: Glutamine

• Glutamine 5g three times daily for 8 weeks is highly effective for post-infectious IBS with diarrhea predominance, particularly when intestinal hyperpermeability is present 1
• This represents a 14-fold improvement over placebo, with 79.6% of patients achieving clinically significant symptom reduction (≥50 point reduction on IBS-SS) 1
• Glutamine normalizes intestinal hyperpermeability, reduces bowel movement frequency from 5.4 to 2.9 daily, and improves stool consistency 1
• The safety profile is excellent with low adverse event rates and no serious complications 1

Secondary Supplement Options

Probiotics

• Multi-strain probiotics taken for at least 8 weeks are more effective than single-strain formulations for global IBS symptoms and abdominal pain 2, 3, 4
• Recommend a 12-week trial period; discontinue if no improvement is observed 2, 3
• Seven out of eleven recent trials (63.6%) showed significant symptom improvement with probiotics versus placebo 4
• The beneficial effects are most distinct with multi-strain supplements used for 8+ weeks 4

Soluble Fiber (Psyllium/Ispaghula)

• Start with low doses (3-4g daily) and increase gradually to avoid exacerbating bloating and gas 2, 5, 3
• Soluble fiber is recommended as first-line dietary supplementation for IBS 2, 3
• Avoid insoluble fiber (wheat bran) as it can worsen symptoms 2

Peppermint Oil

• Peppermint oil has evidence for symptom relief in IBS, particularly for abdominal pain 5, 6
• Can be used as first-line pharmacologic management for meal-related pain 5

Supplements NOT Recommended

• Omega-3 fatty acids are NOT recommended for IBS management based on inflammatory bowel disease guidelines that found no benefit 7
• Glutamine and omega-3 supplementation are specifically NOT recommended in enteral or parenteral nutrition for IBD patients 7
• Vitamin C and fish oils lack specific evidence for post-infectious IBS (evidence exists only for exercise-induced bronchoconstriction) 7

Clinical Algorithm

1. First-line approach: Start glutamine 5g three times daily if post-infectious IBS-D with suspected intestinal hyperpermeability 1
2. Add soluble fiber: Begin psyllium 3-4g daily, titrate slowly 2, 3
3. Consider probiotics: Add multi-strain probiotic for 12-week trial 2, 3, 4
4. Adjunctive therapy: Peppermint oil for abdominal pain if needed 5, 6

Important Caveats

• Glutamine's dramatic efficacy is specifically demonstrated in post-infectious IBS-D with intestinal hyperpermeability—this is the exact population you're asking about 1
• The glutamine study is the highest quality, most recent evidence directly addressing post-infectious IBS with objective endpoints (intestinal permeability normalization) 1
• Regular exercise should be encouraged for all IBS patients as it improves symptoms 2, 3
• Maintain regular meals, adequate hydration (8 glasses daily), and limit caffeine to 3 cups daily 2