A service evaluation of FODMAP restriction, FODMAP reintroduction and long-term follow-up in the dietary management of irritable bowel syndrome.

Background: The dietary restriction of fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAPs), called the low-FODMAP diet (LFD), is frequently used to manage irritable bowel syndrome (IBS). This service evaluation aimed to assess the long-term effectiveness of the LFD in managing IBS symptoms and whether symptom response and dietary adherence to the LFD were associated.

Methods: This observational service evaluation collected data via questionnaires during clinical dietetic appointments for IBS management. Symptom severity was reported at baseline, short term (following FODMAP restriction) and long term (following FODMAP reintroduction). Additional data that captured experiences following the LFD were collected at long-term follow-up.

Results: Of 184 patients, 14% reported satisfactory relief from global symptoms at baseline, which increased to 69% at short-term follow-up and 57% at long-term follow-up (p < 0.001). The most notable improvements in individual symptoms between baseline and long-term follow-up were abdominal bloating (72% baseline, 48% long term, p < 0.001), abdominal pain (61% baseline, 30% long term, p < 0.001) and flatulence (71% baseline, 40% long term, p < 0.001). High adherence with the LFD at short-term follow-up was not associated with long-term symptom improvement, but there was an association between long-term adherence and global symptom severity (p = 0.032). Completion of FODMAP reintroduction as per protocol was associated with long-term symptom improvement (p = 0.049).

Conclusions: The LFD is an effective treatment for managing IBS symptoms in the long term, particularly, when the diet is adhered to and reintroduction is completed as per dietetic education. Further randomised-controlled trials are required to explore the cause-and-effect relationship between LFD and IBS symptom management.