Self-reported Wheat Sensitivity in Irritable Bowel Syndrome and Healthy Subjects: Prevalence of Celiac Markers and Response to Wheat-free Diet

Effects of gluten on dyspeptic symptoms: a systematic review and meta-analysis of clinical trials

CONTEXT

Research on the effects of gluten on dyspeptic symptoms has shown conflicting results.

OBJECTIVE

The aim of this systematic review and meta-analysis of clinical trials was to assess the effects of gluten on dyspeptic symptoms.

DATA SOURCES

A systematic search of the PubMed, ISI Web of Science, Scopus, Cochrane, and Embase online databases was performed up to May 2022.

DATA EXTRACTION

Randomized controlled trials (RCTs) and non-RCTs that examined the impact of a gluten-free diet, a low-gluten diet, or a gluten challenge on dyspeptic symptoms, including early satiety, epigastric pain, bloating, and nausea, were selected independently by 2 authors. The GRADE (Grading of Recommendations Assessment, Development, and Evaluation) framework was used to assess the certainty of the evidence. Results were pooled using a random-effects model and expressed as weighted mean differences (WMDs) and 95%CIs.

DATA ANALYSIS

Of the 7641 citations retrieved, 27 articles (18 RCTs and 9 non-RCTs) were included in the systematic review. Of those, 5 RCTs were eligible for the meta-analysis. The pooled results indicated that gluten challenge significantly increased the severity of bloating (WMD = 0.67; 95%CI, 0.37-0.97; I2 = 81.8%; n = 6), early satiety (WMD = 0.91; 95%CI, 0.58-1.23; I2 = 27.2%; n = 5), and epigastric pain (WMD = 0.46; 95%CI, 0.17-0.75; I2 = 65.8%; n = 6). However, the effect of gluten challenge on the severity of nausea (WMD = 0.13; 95%CI, -0.17 to 0.43; I2 = 0.0%, n = 5) was nonsignificant.

CONCLUSION

Gluten challenge significantly worsened dyspeptic symptoms, including bloating, early satiety, and epigastric pain, but did not affect nausea. These findings suggest that gluten restriction could be efficient in reducing dyspeptic symptoms. Well-designed large RCTs recruiting homogenous groups of patients with functional dyspepsia are needed to clarify the effectiveness of gluten restriction on dyspeptic symptoms.

Self-reported food intolerances in an Indian population: Need for individualization rather than a universal low-FODMAP diet

Background and Aim

Low-fermentable oligo-, di-, and monosaccharides and polyol (FODMAP) diets have been recommended for individuals with food intolerance and irritable bowel syndrome (IBS). Individual food intolerances may, however, not correspond to the FODMAP content alone.

Methods

We conducted a survey on self-reported intolerance to articles of food commonly identified as high FODMAP in 400 healthy Indian subjects (median age 40 years; 69% men) and 204 consecutive consenting patients with IBS (median age 36 years; 58% men).

Results

One-hundred seventy-nine (44.8%) healthy subjects and 147 (72.1%) patients with IBS reported some food intolerance (P < 0.00001); the latter reported intolerance to all items (except nuts) more frequently than healthy subjects. The prevalence, however, varied from 2.5 to 32%. Milk intolerance was reported equally commonly by healthy subjects and patients (23% vs 29.9%). Twenty-three (11.3%) patients and no healthy subjects reported wheat sensitivity. The IBS diarrhea subgroup reported intolerance to milk, pulses, capsicum, cauliflower, leafy vegetables, and dry fruits more frequently than the constipation subgroup.

Conclusion

From among a list of high-FODMAP items, individuals' intolerance varied widely, suggesting that individuals should be the final judge in deciding their elimination diets rather than devise them based on the FODMAP content alone. As in the West, food intolerance was reported more commonly by patients with IBS, especially those with diarrhea, than by healthy individuals. Also noteworthy is the low prevalence of milk intolerance in a subcontinent labeled as high in lactose intolerance. Unlike in the West, wheat intolerance was not reported by any healthy individual.

Nonceliac gluten sensitivity

PURPOSE OF REVIEW

To describe recent advances on nonceliac gluten sensitivity (NCGS), a recently described disorder characterized by variable symptoms and frequent irritable bowel syndrome (IBS)-like manifestations.

RECENT FINDINGS

The recent description of disease-triggering wheat components other than gluten, such as fructans and amylase-trypsin inhibitors (ATIs), definitely suggests that nonceliac wheat sensitivity (NCWS) is a better 'umbrella' terminology than NCGS. Self-reported NCWS is very common worldwide, particularly in patients seen at the gastroenterology clinic, but many of these diagnoses are not confirmed by standard clinical criteria. A biomarker of NCWS is still lacking, however, subtle histological features at the small intestinal biopsy may facilitate diagnosis. Treatment of NCWS is based on the gluten-free diet (GFD). The GFD has proven to be an effective treatment of a significant proportion of NCWS-related IBS patients. Dietary therapies for IBS, including the GFD, should be offered by dietitians who first assess dietary triggers and then tailor the intervention according to patient choice. Pioneer studies are under way to test the therapeutic efficacy of supplemental gluten-digesting enzyme preparations in patients with NCWS.

SUMMARY

Recent studies highlight interesting pathophysiological and clinical features of NCWS. Many questions remain, however, unanswered, such as the epidemiology, a biomarker(s), and the natural history of this clinical entity.

Progress in understanding of relationship between irritable bowel syndrome and food intolerance

Irritable bowel syndrome (IBS) is a common functional gastrointestinal disorder, and more and more studies have found that food intolerance is involved in the pathogenesis of IBS. About two-thirds of IBS patients experience clinical symptoms induced by food intolerance, including gastrointestinal symptoms such as abdominal pain, bloating, diarrhea, or constipation. A small number of patients also experience circulatory, respiratory, neurological, and other systemic symptoms. The exact mechanism by which food intolerance is involved in IBS is not fully understood. Common types of food intolerance include lactose intolerance, gluten intolerance, FODMAP intolerance, and histamine intolerance, among which lactose intolerance and FODMAP intolerance are more common in IBS patients. In this paper, we review the types of food intolerance in IBS and the role of food intolerance in the pathogenesis and intervention of IBS.