Gut microbiome, diet and symptom interactions in irritable bowel syndrome

While several studies have documented associations between dietary habits and microbiota composition and function in healthy subjects, no study explored these associations in patients with irritable bowel syndrome (IBS), and especially in relation to symptoms. Here, we used a novel approach that combined data from 4-day food diary, integrated into a food tree, together with gut microbiota (shotgun metagenomic) for IBS patients (N=149) and healthy subjects (N=52). Paired microbiota and food-based trees allowed to detect new association between subspecies and diet. Combining co-inertia analysis and linear regression models, exhaled gas levels and symptom severity could be predicted from metagenomic and dietary data. IBS patients with severe symptoms had a diet enriched in food items of poorer quality, a high abundance of gut microbial enzymes involved in hydrogen metabolism in correlation with animal carbohydrate (mucin/meat-derived) metabolism. Our study provides unprecedented resolution of diet-microbiota-symptom interactions and ultimately paves the way for personalized nutritional recommendations.