Irritable bowel syndrome (IBS) is a “common gastrointestinal functional disease, characterized by chronic abdominal pain or discomfort, along with diarrhea, constipation (or a pattern of alternation between the two), defecation urgency, tenesmus bloating, and abdominal distension.”1
Patients with IBS are affected by numerous comorbidities, notably fibromyalgia syndrome (FMS). This condition, which is characterized by chronic widespread pain, occurs in 20% to 32% of individuals with IBS;2 in turn, 32% to 70% of individuals with FMS also meet criteria for IBS.3,4,5
Celiac disease (CD), once considered rare, has been garnering increased attention as being more prevalent than once thought. Indeed, CD is now regarded as the “most common autoimmune enteropathy in western countries.”6
However, it is still underdiagnosed, and its prevalence continues to be underestimated.1 Incidence of CD in patients with IBS is more than seven-fold that of the general population.7,8 In fact, it is recommended that patients with IBS also be tested for CD.9
Individuals with CD display gluten sensitivity, and their symptoms can be reduced or resolved when they eliminate gluten from their diets. Serum assays can confirm the presence of gluten sensitivity, and gluten challenge can confirm the diagnosis by reversing improvement in serum antibodies.10
There may be a causal link between IBS, FMS, and multi-symptomatic forms of gluten sensitivity (including CD).1 Some cases with overlapping symptoms share similar clinical features.11,12 Moreover, some patients with comorbid FMS and CD experience symptom resolution after the removal of gluten from their diets.13,14
The Impact of a Gluten-Free Diet on Comorbid IBS, FMS, and CD
A recent pilot study conducted by a group of researchers in Spain examines the impact of a gluten-free diet (GFD) on patients with comorbid IBS, FMS, and CD.1 Rodrigo and colleagues studied 229 patients with IBS, in whom 104 (45.4%) also had FMS. Among these, seven patients (6.7%) had CD.
These patients had very severe IBS and FM, and their quality of life (QOL) was extremely poor at baseline, as measured by the Fibromyalgia Impact Questionnaire (FIQ), Health Assessment Questionnaire (HAQ), Tender Point (TP) test, Short Form Health Survey (SF-36) tests, and the Visual Analogue Scales (VAS) for gastrointestinal complaints, pain, fatigue, prescribed drugs for symptoms control, and tissue-Trans-Glutaminase (tTG) serum levels. Subjects were assessed at baseline and then one year after initiation of the GFD.
At baseline, all seven patients were experiencing severe gastrointestinal symptoms, including diffuse abdominal pain and discomfort, constipation, diarrhea, alternating diarrhea/constipation, bloating, and heartburn.
Additionally, all experienced FMS symptoms, including widespread soft tissue pain, abnormal fatigue, sleep disturbances, and cognitive dysfunction. They also suffered from osteoporosis and temporomandibular joint disorders (TMJs).
All subjects showed villous atrophy in duodenal biopsies and were also HLA-DQ2/DQ8-positive. All patients had been taking a variety of medications to treat these conditions, including analgesics, proton pump inhibitors, antidepressants, and anxiolytics.
After one year of GFD, the patients showed marked improvement. All selected outcome measure scores (TPs, FIQ, HAQ, SF-36, and VAS) improved by more than 50% from baseline (P < 0.001). Serum concentrations of tTG normalized in all cases (P < 0.05). Additionally, both the individual and the global SF-36 scores improved, as compared to baseline.