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Original research
Efficacy of individualised diets in patients with irritable bowel syndrome: a randomised controlled trial
  1. Ather Ali1,
  2. Theresa R Weiss1,
  3. Douglas McKee2,
  4. Alisa Scherban1,
  5. Sumiya Khan1,
  6. Maxine R Fields1,
  7. Damian Apollo1,
  8. Wajahat Z Mehal1
  1. 1School of Medicine, Yale University, New Haven, Connecticut, USA
  2. 2Department of Economics, Cornell University, Ithaca, New York, USA
  1. Correspondence to Dr. Ather Ali; ather.ali{at}


Background Patients with irritable bowel syndrome (IBS) are often placed on diets guided by food intolerance assays, although these have not been validated. We assessed the effects of individualised diets in patients with IBS guided by a leucocyte activation test.

Methods This is a parallel-group, double-blind, randomised controlled trial of 58 adults with IBS seen at an academic health centre in Northeast USA. Peripheral venous blood was analysed using a leucocyte activation test; individual foods were reported to produce positive or negative results. Participants were randomised to a 4-week diet with either individualised guidance to eliminate foods with positive assay results and allow foods with negative assay results (intervention), or with individualised guidance, matched in rigour and complexity, to eliminate foods with negative assay results and allow foods with positive assay results (comparison). The primary outcome was between-group differences in the IBS Global Improvement Scale (GIS). Secondary outcomes included reductions in IBS Symptom Severity Scale (SSS) scores and increases in IBS Adequate Relief (AR) and Quality of Life (QOL) scores. An aptamer-based proteomic analysis was conducted in strong responders.

Results The intervention group had significantly greater increases in mean GIS score after 4 weeks (0.86 vs comparison; 95% CI 0.05 to 1.67; p=0.04) and 8 weeks (1.22 vs comparison; 95% CI 0.22 to 2.22; p=0.02). The intervention group also had significantly greater reductions in mean SSS score at 4 weeks (–61.78 vs comparison; 95% CI –4.43 to –119.14; p=0.04) and 8 weeks (–66.42 vs comparison; 95% CI –5.75 to –127.09; p=0.03). There were no significant differences between intervention and comparison groups in mean AR or QOL scores. A reduction in neutrophil elastase concentration was associated with reduced symptoms.

Conclusions Elimination diets guided by leucocyte activation tests reduced symptoms. These findings could lead to insights into the pathophysiology of IBS.

Trial registration number NCT02186743.

  • Irritable Bowel Syndrome
  • Quality Of Life
  • Dietary Factors

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  • Contributors AA designed the study, drafted the manuscript, obtained funding, interpreted the data and was responsible for overall supervision of the study. He has full access to all the data in the study, but was blinded until study completion. TRW was involved with the acquisition of data, critical revision of the manuscript for important intellectual content, administrative support and supervision of the clinical staff. DM conducted and is responsible for the data analysis, statistical analysis and critical revision of the manuscript for important intellectual content. AS and SK were involved with the acquisition of the data. MRF was involved with data analysis and critical revision of the manuscript. DA was involved with the design of the study. WZM was involved with the conception and design of the study, statistical analysis, interpretation of the data and critical revision of the manuscript for important intellectual content. WZM and AA take responsibility for the integrity of the data and the accuracy of the data analysis.

  • Funding This study was funded by Cell Science Systems, Corp. (Deerfield Beach, FL). The sponsor had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; and preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication. This publication used resources from CTSA Grant Number UL1 TR000142 from the National Center for Advancing Translational Science (NCATS), a component of the National Institutes of Health (NIH). Its contents are solely the responsibility of the authors and do not necessarily represent the official view of NIH.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Human Investigation Committee of Yale University.

  • Provenance and peer review Not commissioned; externally peer reviewed.

  • Data sharing statement Individual participant data that underlie the results reported in this article, after de-identification (text, tables, figures and appendices), and/or the study protocol will be shared beginning 9 months and ending 36 months after article publication. Data will be shared with investigators whose proposed use of the data has been approved by an independent review committee ('learned intermediary') identified for these purposes: (1) for individual participant data meta-analysis, and (2) researchers who provide a methodologically sound proposal. Proposals should be directed to To gain access, data requestors will need to sign a data access agreement.