Inflamm Bowel Dis. 2024 Aug 23:izae185. doi: 10.1093/ibd/izae185. Online ahead of print.

Alice S Day ^1 2 3, Tessa M Ballard ^1 4, Chu K Yao ⁵, Peter R Gibson ⁵, Robert V Bryant ^1 2 3

Author information

¹Department of Gastroenterology and Hepatology, Inflammatory Bowel Disease Services, The Queen Elizabeth Hospital, 28 Woodville Road, Woodville South 5011, South Australia, Australia.

²School of Medicine, Faculty of Health Sciences, University of Adelaide, Frome Road, Adelaide 5000, South Australia, Australia.

³Inflammatory Bowel Disease Research Group, Basil Hetzel Institute, 33 Woodville Road, Woodville South 5011, South Australia, Australia.

⁴Discipline of Nutrition and Dietetics, College of Nursing and Health Sciences, Flinders University, GPO Box 2100, Adelaide 5001, South Australia, Australia.

⁵Department of Gastroenterology, Central Clinical School, Monash University & Alfred Hospital, 99 Commercial Road, Melbourne 3004, Victoria, Australia.

Abstract

Diet therapy for inflammatory bowel disease (IBD) is an international research priority but guidance for IBD-specific diet trial design is lacking. This review critically evaluates key elements of prospective IBD food-based intervention trials and identifies gaps. Electronic databases were searched for interventional IBD diet studies. Prospective primary studies/trials were included if used food-based dietary strategies. Forty studies/trials evaluating 29 food-based strategies as therapy for IBD were identified. Considerable heterogeneity in diets, trial design, and methodology exists. Thirty-one trials (78%) intended the diet to modulate inflammation but 14/31 (46%) did not have a primary endpoint measuring an objective change in inflammatory activity and 20/31 (65%) controlled for medication stability prior to application of diet at baseline. Higher-quality IBD diet trials used symptom-based assessment tools coupled with an objective evaluation of inflammatory activity. Dietary advice trials are the most common. One-third of trials developed and administered diet education without a dietitian. Evaluation and reporting on adherence to diet therapy occurred in <60% of trials. Failure to include or report on key elements of trial design reduced the interpretability and validity of the results. This is a considerable limitation to advancing scientific knowledge in this area. Diet therapy trials should adhere to similar rigorous quality standards used to develop other IBD therapies. Therefore, a set of practical recommendations was generated to provide the authors' perspective to help inform the future design of high-quality IBD diet trials.