Which Diet is Best for Irritable Bowel Syndrome? A Randomized Trial

A Rej et al. Clin Gastroenterol Hepatol 2022; 20: 2876-2887. Open Access! Efficacy and Acceptability of Dietary Therapies in Non-Constipated Irritable Bowel Syndrome: A Randomized Trial of Traditional Dietary Advice, the Low FODMAP Diet, and the Gluten-Free Diet

Methods: In patients (n=99) with Rome IV–defined non-constipated IBS, outcomes after randomization to one of three diets were compared. The “traditional dietary advice” group: “Its principles include adopting healthy, sensible eating patterns such as having regular meals, never eating too little/too much, maintaining adequate hydration, and reducing the intake of (1) alcohol/caffeine/fizzy drinks, (2) fatty/spicy/processed foods, (3) fresh fruit to a maximum of 3 per day, (4) fiber and other commonly consumed gas-producing foods (eg, beans, bread, sweeteners, etc), and (5) addressing any perceived food intolerances (eg, dairy).” (Link: National Institute for Health and Care Excellence advice on IBS mgt). The Gluten-Free diet allowed for cross-contamination. All patients had specialist dietary counseling.

Key findings:

  • All three diets resulted in improvement. The primary end point of ≥50-point reduction in IBS-SSS was met by 42% (n = 14/33) undertaking TDA, 55% (n = 18/33) for LFD, and 58% (n = 19/33) for GFD (P = .43)
  • Alterations in stool dysbiosis index were similar across the diets, with 22%–29% showing reduced dysbiosis
  • “The pragmatic study design, whereby the responsibility was left on patients to undertake the diets following appropriate education, means our findings can be generalized”

My take: All three diet approaches would be appropriate to reduce IBS symptoms, thought the TDA is the easiest for patients.

Related blog posts:

Which Diet is Best for Irritable Bowel Syndrome?

As noted in this blog previously, there has been increasing evidence that a low FODMAPs (fermentable oligo-, di-, monosaccharides and polyols) diet is an effective option for irritable bowel syndrome (IBS) in adults and children. Now, a study (L Bohn et al. Gastroenterol 2015; 149: 1399-1407) directly compares a low FODMAPs diet with an IBS diet in a multicenter, parallel, single-blind study of 75 patients (adults) with Rome III criteria for IBS.

The comparison IBS diet recommended regular meal patterns, avoidance of large meals, reduced intake of fat and reduced insoluble fibers, caffeine, and gas-producing foods, such as beans, cabbage and onions.  In addition, this diet recommended avoidance of spicy foods, coffee, alcohol, soft drinks, and sweeteners that end with “-ol.” This diet has been recommended by the British Dietetic Association and by the National Institute for Health and Care Excellence (NICE).  NICE Guidelines for IBS

Key findings:

  • 67 patients completed the study.  The severity of IBS symptoms improved in both groups (P<.0001) without a difference between the two groups
  • 19 (50%) of low FODMAPs had reductions in IBS severity scores of >50 compared with baseline and 17 patients (46%) in the ‘traditional’ IBS diet group had this degree of improvement.

My take: Diet changes often result in symptom improvement in IBS.  Both of these diets can be recommended in patients with IBS.

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