FODMAP meal challenge test: a novel investigation to predict response to low‐FODMAP diet in non‐constipating irritable bowel syndrome

Abstract Background Though a low‐FODMAP diet improves 50% irritable bowel syndrome (IBS) patients, regional dietary variations, vegetarianism, and long‐term nutritional consequences challenge its implementation. We aimed developing a FODMAP meal challenge test (FMCT). We prospectively studied whether (i) high‐ than low‐FODMAP foods produce more breath H 2 among IBS patients than controls; (ii) post‐meal symptoms relate to breath H 2 ; and (iii) novel FMCT predicts response to a low‐FODMAP diet? Methods Forty Rome III IBS and 20 healthy controls underwent an eight‐hour H 2 breath test following a low‐ (rice, brinjal, corn, and banana [450 Kcal]) and a high‐FODMAP meal (wheat, kidney bean, pulse, and card [450 Kcal]). Breath H 2 (every 15 min) and symptoms following low‐ and high‐FODMAP meals were recorded. IBS‐symptom severity scores were recorded every month for 3‐months on low‐FODMAP diet. Results Forty Rome III IBS (19 Rome IV positive) were comparable to 20 controls in age and gender. IBS patients ( n = 39 excluding one H 2 non‐producer) and controls produced more breath H 2 after high‐ (greater in IBS) than low‐FODMAP meal. Post‐meal symptoms were commoner in IBS (4/40 [10%] and 27/40 [67.5%] with low‐ and high‐FODMAP, respectively [ P < 0.00001]; none in healthy). IBS patients developing post‐high‐FODMAP meal symptoms produced greater H 2 (18 PPM [IQR 10.5–23] vs 6 [0–7.2]; P < 0.001). A positive FMCT (breath H 2 > 10 PPM above basal with symptoms following high‐FODMAP food) had sensitivity, specificity, and diagnostic accuracy of 78.6%, 66.6%, and 75.6%, respectively, to predict low‐FODMAP diet response. Conclusions The novel FMCT predicts response to a low‐FODMAP diet in IBS.