Introduction A low FODMAPs diet is an effective dietary intervention for the management of irritable bowel syndrome (IBS). We hypothesised that hydrogen breath testing (HBT) for lactose and fructose intolerance would identify potential responders. Secondly we hypothesised that greater improvement would be seen in diarrhoea predominant (IBS-D) than other subtypes.

Methods 167 consecutive patients with a Rome III IBS diagnosis who completed low FODMAPs dietary education therapy were analysed. Symptoms were assessed at baseline and follow up (median 63 days post-treatment) via self-administered questionnaire. The primary endpoint was a symptom severity score (scale 0–5) based on pain, bloating, constipation and diarrhoea. According to clinician choice, some patients underwent HBT with fructose 30 gm (n = 74) and lactose 30 gm (n = 103).

Results Subtypes were IBS-D (n = 91, 67 f, mean age 42), IBS-C (n = 41, 35 f, mean age 45) and IBS-M (n = 34, 29 f, mean age 36). Across all patients, an improvement in symptom severity (2.4 to 1.6, p < 0.001) was observed following low FODMAPs diet. Patients with a positive fructose BT (26/74, 35%) experienced statistically greater improvement in symptom severity (2.7 to 1.5, p < 0.01), but not those with positive lactose BT (36/102, 35%). Compared to IBS-D (2.4 to 1.5) and IBS-C (2.4 to 1.6), a greater response was seen in IBS-M (3.1 to 1.9, p < 0.01). Response was correlated to baseline symptom severity (r = 0.45, p < 0.001).

Conclusion A low FODMAP diet may particularly beneficial in patients with fructose malabsorption. Severity of symptoms at baseline may predict degree of improvement which may explain the greater response seen in IBS-M patients in this study.

A low FODMAP diet may particularly beneficial in patients with fructose malabsorption. Severity of symptoms at baseline may predict degree of improvement which may explain the greater response seen in IBS-M patients in this study.

Disclosure of Interest None Declared