Is zinc sulphate (zinc sulfate) effective in managing irritable bowel syndrome (IBS) symptoms in an adult patient?

Does Zinc Sulphate Have a Role in Adult IBS?

No, zinc sulphate is not recommended for the treatment of irritable bowel syndrome in adults, as it is not included in any established treatment guidelines and lacks clinical trial evidence demonstrating efficacy for IBS symptoms.

Evidence from Clinical Guidelines

The most recent and comprehensive guidelines for IBS management do not mention zinc supplementation as a treatment option:

• The 2021 British Society of Gastroenterology guidelines provide detailed recommendations for IBS treatment including dietary modifications, pharmacological therapies, and psychological interventions, but make no mention of zinc supplementation 1

• The 2007 BSG guidelines similarly outline evidence-based treatments including antispasmodics, tricyclic antidepressants, 5-HT3 antagonists, 5-HT4 agonists, and SSRIs, with no reference to zinc therapy 1

• Multiple comprehensive treatment algorithms from major gastroenterology societies recommend starting with lifestyle modifications, soluble fiber, probiotics, and then escalating to prescription medications, but zinc is absent from all treatment pathways 2, 3

The Single Observational Study

Only one observational study has examined zinc in IBS:

• A 2022 case-control study found that IBS-D patients had lower serum zinc levels compared to controls and that serum zinc correlated negatively with zonulin (a marker of intestinal permeability) 4

• However, this was purely observational - it did not test whether zinc supplementation actually improves IBS symptoms 4

• The authors themselves concluded that "clinical trial studies are warranted to evaluate this finding" 4

Why This Matters Clinically

The absence of zinc from evidence-based guidelines is significant because:

• IBS treatment guidelines are based on randomized controlled trials demonstrating efficacy for symptom relief, quality of life, and functional outcomes 1

• Established first-line treatments (soluble fiber, antispasmodics, probiotics) and second-line treatments (tricyclic antidepressants, 5-HT3 antagonists, secretagogues) all have RCT evidence supporting their use 2, 3

• Multiple comprehensive reviews of IBS pharmacotherapy from 1992 to 2024 do not mention zinc as a therapeutic option 5, 6, 7, 8

What You Should Do Instead

For an adult patient with IBS, follow the established treatment algorithm:

1. Start with lifestyle and dietary modifications: regular physical exercise, soluble fiber (ispaghula 3-4 g/day gradually increased), and traditional dietary advice 3

2. For persistent symptoms, add symptom-targeted therapy:

   • Antispasmodics for abdominal pain 2, 3
   • Loperamide for diarrhea (IBS-D) 2, 3
   • Osmotic laxatives for constipation (IBS-C) 2

3. For refractory symptoms, escalate to:

   • Tricyclic antidepressants (amitriptyline 10-50 mg daily) for global symptoms and pain 2, 3
   • 5-HT3 antagonists for IBS-D 2
   • Secretagogues (linaclotide, lubiprostone) for IBS-C 2

4. Consider psychological therapies (CBT, gut-directed hypnotherapy) when symptoms persist despite 12 months of pharmacological treatment 2, 3

Critical Pitfall to Avoid

Do not prescribe unproven supplements like zinc sulphate based on a single observational study when multiple evidence-based treatments with demonstrated efficacy are available 1, 2, 3. This delays effective treatment and may give patients false hope while their quality of life continues to suffer.