Coeliac Disease vs IBS — Clinical Trial Comparison
Coeliac Disease
Autoimmune reaction to gluten damaging the gut
IBS
Functional gut disorder with pain and altered bowel habits
Coeliac disease and irritable bowel syndrome (IBS) share many symptoms — bloating, abdominal pain, diarrhoea, and fatigue — which makes them easy to confuse. However, coeliac disease is an autoimmune condition triggered by gluten that damages the small intestine, while IBS is a functional disorder with no visible gut damage. Both have active UK trial programmes, though their treatment approaches are entirely different.
Key Differences at a Glance
| Feature | Coeliac Disease | IBS |
|---|---|---|
| Nature | Autoimmune disease — gluten triggers immune attack on small intestine | Functional disorder — gut-brain axis dysregulation, no structural damage |
| UK prevalence | ~1% (~680,000, with ~500,000 undiagnosed) | ~10–15% of adults (~6–9 million) |
| Diagnosis | Blood tests (tTG-IgA, EMA) + endoscopy/biopsy showing villous atrophy | Rome IV criteria (symptom-based, after excluding other conditions) |
| Trigger | Gluten (wheat, barley, rye) — specific, measurable | Multiple: stress, food intolerances, gut microbiome changes, FODMAPs |
| Intestinal damage | Yes — villous atrophy, crypt hyperplasia, intraepithelial lymphocytes | No visible damage — normal endoscopy and histology |
| Current treatment | Strict lifelong gluten-free diet (no medication approved) | Dietary modification, antispasmodics, laxatives/antidiarrhoeals, low-dose antidepressants, psychological therapies |
Clinical Trial Availability
| Trial Aspect | Coeliac Disease | IBS |
|---|---|---|
| UK trials actively recruiting | 10–15 studies | 20–30 studies |
| Most common trial phase | Phase 1–2 (building drug pipeline) | Phase 2–4 (dietary, psychological, pharmacological) |
| Top interventions tested | Gluten detoxification enzymes, tight junction modulators, desensitisation vaccines, microbiome therapies | Low-FODMAP diet, gut-directed hypnotherapy, rifaximin, microbiome therapies, peppermint oil formulations |
| Drug trials | Growing (larazotide, ALV003, TAK-062) | Moderate (IBS-D and IBS-C specific agents) |
| Dietary trials | Minimal (diet is already the treatment) | Major category (low-FODMAP, exclusion diets, probiotics) |
| Psychological trials | Limited (adjustment to diagnosis, QoL) | Major category (gut-directed hypnotherapy, CBT, mindfulness) |
Exciting Emerging Treatments
Coeliac Disease Trials
- Larazotide acetate (tight junction modulator) — preventing gluten from crossing the intestinal barrier
- ALV003 / TAK-062 (gluten detoxification enzymes) — breaking down gluten before it triggers immune response
- Nexvax2-style desensitisation — vaccine-like approach to build gluten tolerance
- Anti-IL-15 therapies — targeting the specific immune pathway activated in coeliac disease
- Microbiome-based therapies — modifying gut bacteria to reduce gluten sensitivity
- Transglutaminase inhibitors — blocking the enzyme that makes gluten more immunogenic
IBS Trials
- Gut-directed hypnotherapy (digital delivery) — app-based programmes showing strong results
- Rifaximin for IBS-D — targeted antibiotic reducing bacterial overgrowth
- Faecal microbiota transplantation (FMT) — transplanting healthy donor microbiome
- Low-FODMAP diet optimisation — personalising reintroduction phases
- Tenapanor and IBAT inhibitors for IBS-C — novel mechanisms for constipation-predominant IBS
- Peppermint oil formulations — sustained-release enteric-coated capsules
💡 Still symptomatic on a gluten-free diet? You're not alone
Up to 30% of coeliac patients continue to have symptoms despite strict gluten avoidance. This may be due to microscopic gluten exposure, overlapping IBS, or refractory coeliac disease. Several UK trials specifically target this population — testing adjunct therapies that work alongside a gluten-free diet. If you're strictly gluten-free but still symptomatic, ask about research options.
Eligibility Differences
Coeliac Disease Trial Criteria
- Confirmed diagnosis: positive tTG-IgA/EMA and/or biopsy-proven villous atrophy
- HLA-DQ2/DQ8 genotype may be required (genetic confirmation of susceptibility)
- Gluten challenge may be required for some trials (reintroducing gluten under medical supervision)
- Current diet: some trials require strict gluten-free diet adherence, others test treatment during gluten exposure
- Symptom severity scoring (Celiac Symptom Index, GSRS)
IBS Trial Criteria
- Rome IV IBS criteria met (recurrent abdominal pain ≥1 day/week associated with defecation or change in stool frequency/form)
- IBS subtype specified: IBS-C (constipation), IBS-D (diarrhoea), IBS-M (mixed), IBS-U (unclassified)
- Normal coeliac screening (tTG) — important to exclude coeliac before IBS trial enrolment
- Normal colonoscopy if age-appropriate (to exclude inflammatory bowel disease)
- Symptom duration typically ≥ 6 months
🌾 Coeliac Trials
Find actively recruiting coeliac disease clinical trials across the UK
View Coeliac Trials