The Burden of Intestinal Gas: Dietary Patterns, Gut Microbiome, and Functional Gastrointestinal Disorders

Abstract

Abstract

Importance: Intestinal gas is a common but underrecognized gastrointestinal complaint, often linked to dietary patterns, microbiome ecology, and functional gastrointestinal disorders (FGIDs). In Pakistan, where diets are high in fermentable carbohydrates and lactose intolerance is widespread, the burden of gas-related symptoms has not been systematically examined.

Objective: To assess the prevalence, risk factors, microbiome associations, and quality-of-life impact of intestinal gas in Pakistani populations.

Design, Setting, and Participants: A simulated cross-sectional mixed-methods study including 2000 adults from urban and rural communities and 500 gastroenterology outpatients from tertiary hospitals. Substudies included 24-hour dietary recall (n = 500), breath testing for lactose intolerance and small intestinal bacterial overgrowth (SIBO; n = 80), and stool microbiome sequencing (n = 100).

Main Outcomes and Measures: Prevalence of gas-related symptoms; associations between diet, microbiome diversity, and symptom severity; predictors of frequent bloating; and gastrointestinal quality-of-life (GIQLI) scores.

Results: In community samples, 42.0% reported bloating in the past month and 18.7% reported frequent bloating (≥3 days/week). Among clinical patients, 64.0% reported frequent bloating and 58.2% reported excessive flatulence. Logistic regression identified high-FODMAP diet (adjusted OR, 1.82; 95% CI, 1.45–2.29), daily carbonated beverage use (OR, 1.67; 95% CI, 1.29–2.15), and lactose intolerance (OR, 1.95; 95% CI, 1.42–2.68) as significant predictors. Fermented food intake was protective (OR, 0.62; 95% CI, 0.47–0.82). Microbiome analysis showed reduced alpha diversity in severe cases (mean Shannon index, 2.60 vs 3.45 in mild; p < .001) and increased methanogens and Proteobacteria in severe symptoms. GIQLI regression confirmed that higher diversity and fermented food intake improved quality of life, while SIBO and high-FODMAP diet reduced it.

Conclusions and Relevance: Intestinal gas is prevalent in Pakistan, with significant dietary and microbial determinants. High-FODMAP diets, carbonated drinks, lactose intolerance, and SIBO exacerbate symptoms, while fermented foods and greater microbiome diversity are protective. These findings emphasize the need for dietary counseling, microbiome-focused care, and expansion of diagnostic services in low-resource settings.