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.

BACKGROUND & AIMS: Various diets are proposed as first-line therapies for non-constipated irritable bowel syndrome (IBS) despite insufficient or low-quality evidence. We performed a randomized trial comparing traditional dietary advice (TDA) against the low FODMAP diet (LFD) and gluten-free diet (GFD). METHODS: Patients with Rome IV-defined non-constipated IBS were randomized to TDA, LFD, or GFD (the latter allowing for minute gluten cross-contamination). The primary end point was clinical response after 4 weeks of dietary intervention, as defined by ≥50-point reduction in IBS symptom severity score (IBS-SSS). Secondary end points included (1) changes in individual IBS-SSS items within clinical responders, (2) acceptability and food-related quality of life with dietary therapy, (3) changes in nutritional intake, (4) alterations in stool dysbiosis index, and (5) baseline factors associated with clinical response. RESULTS: 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). Responders had similar improvements in IBS-SSS items regardless of their allocated diet. Individuals found TDA cheaper (P < .01), less time-consuming to shop (P < .01), and easier to follow when eating out (P = .03) than the GFD and LFD. TDA was also easier to incorporate into daily life than the LFD (P = .02). Overall reductions in micronutrient and macronutrient intake did not significantly differ across the diets. However, the LFD group had the greatest reduction in total FODMAP content (27.7 g/day before intervention to 7.6 g/day at week 4) compared with the GFD (27.4 g/day to 22.4 g/day) and TDA (24.9 g/day to 15.2 g/day) (P < .01). Alterations in stool dysbiosis index were similar across the diets, with 22%-29% showing reduced dysbiosis, 35%-39% no change, and 35%-40% increased dysbiosis (P = .99). Baseline clinical characteristics and stool dysbiosis index did not predict response to dietary therapy. CONCLUSIONS: TDA, LFD, and GFD are effective approaches in non-constipated IBS, but TDA is the most patient-friendly in terms of cost and convenience. We recommend TDA as the first-choice dietary therapy in non-constipated IBS, with LFD and GFD reserved according to specific patient preferences and specialist dietetic input. CLINICALTRIALS: gov: NCT04072991.

Dietetic Management of Irritable Bowel Syndrome: A National Survey of Dietary Approaches and Decision-making Factors.

BACKGROUND AND AIMS: There has been a growing emphasis on dietary therapies for irritable bowel syndrome (IBS). Furthermore, there has been an evolving evidence base for the low fermentable oligosaccharides, disaccharides, monosaccharides and polyols (FODMAP) diet, gluten-free diet (GFD), and lactose-free diet. This study examines the dietary approaches employed and the factors influencing dietetic decision-making for IBS interventions. METHODS: Participants, including registered dietitians and nutritionists, were recruited from diverse healthcare settings at the point of registration for the 4th Sheffield National Dietetic Gastroenterology Symposium, 2023. A 15-question online survey investigated the practices of dietitians and nutritionists in managing IBS patients, covering dietary approaches, decision-making factors, and patient education. The evidence base for different dietary interventions was provided and a follow-up survey assessed symposium attendees, views on current IBS dietary practices. RESULTS: Out of 731 respondents, primarily registered dietitians (93%) and females (93%), 54% spent 10-50% of clinic time on IBS. Respondents noted that a GFD (34%), low lactose (32%), and traditional dietary advice (TDA) (18%) were the most frequently used dietary interventions that patients try before seeking professional advice. Delegates were asked to rank their dietary intervention preferences pre- and post-meeting (after the evidence base had been presented): TDA pre-meeting 75% versus post-meeting 87% (p=0.04), fibre modification 59% versus 6% (p<0.0001), low FODMAP 25% versus 10% (p=0.0001), low lactose 12% versus 62% (p<0.0001) and GFD 6% to 23% (p<0.0001). CONCLUSIONS: TDA remains the choice of diet for dietitians. After our educational event, the use of low-lactose and gluten-free diet significantly increased. Factors influencing the decision-making process were based on patient acceptability, counselling time, supporting evidence base and dietary triggers.

The low FODMAP diet for IBS; A multicentre UK study assessing long term follow up.

BACKGROUND: The low FODMAP diet (LFD) is effective in managing irritable bowel syndrome (IBS) in the short term. This study assessed the long-term effect of the LFD on symptoms, nutritional composition and socialising. METHODS: Patients with IBS who received dietetic-led LFD advice were approached at long term follow up (>6 months post LFD advice) from six centres across the United Kingdom. Participants completed questionnaires assessing gastrointestinal symptoms, adherence, nutritional intake, dietary acceptability and food related quality of life (QOL). RESULTS: 205 participants completed the study, with a mean follow up of 44 months (3.7 years). Adequate symptom relief was noted in 60% of individuals at long term follow up, with 76% being on the personalisation phase of the LFD (pLFD). Mean nutritional intake did not differ between individuals on the pLFD versus habitual diet, with no difference in fructan intake (2.9 g/d vs 2.9 g/d, p = 0.96). The majority (80%) of individuals on the pLFD consumed specific 'free-from' products at the long term, with the purchase of gluten or wheat free products being the commonest (68%). CONCLUSION: The majority of patients follow the pLFD in the long term, with a large proportion purchasing gluten or wheat free products to manage their symptoms.