Effect of a Low FODMAP Diet in Irritable Bowel Syndrome and Functional Constipation with Bloating: a Randomized Double-Blind Controlled Trial with Microbiota, Intestinal Gas, and Metabolomic Analysis
试验速览
- 阶段
- 不适用
- 状态
- 尚未招募
- 入组人数
- 34
- 主要终点
- Change in Bloating Severity (VAS)
研究概览
简要总结
This clinical study aims to evaluate the effects of a low FODMAP diet compared to a high FODMAP diet in patients with Irritable Bowel Syndrome (IBS) and Functional Constipation (FC) with predominant bloating. The study is a randomized, double-blind, controlled trial designed to assess whether a diet low in fermentable carbohydrates can improve bloating symptoms, gut microbiota composition, intestinal gas production, and metabolic outputs.
Patients meeting the Rome IV criteria for IBS or FC with persistent bloating will be enrolled and randomly assigned to receive either a low or high FODMAP diet for two weeks. Meals will be standardized to control FODMAPs composition, ensuring that FODMAP content is the primary variable.
The primary endpoint is the proportion of participants with a ≥30% reduction in bloating severity, measured using the Visual Analog Scale (VAS). Secondary outcomes include changes in global IBS symptoms, abdominal pain, bowel movements, stool consistency, microbiota diversity, hydrogen/methane gas production, and metabolomic profiles.
This study will contribute to the growing body of evidence supporting dietary management in disorders of gut-brain interaction (DGBI), particularly in bloating-predominant IBS and FC, and will provide insights into the mechanisms linking diet, gut microbiota, and symptom improvement.
详细描述
Irritable Bowel Syndrome (IBS) and Functional Constipation (FC) are chronic Disorders of Gut-Brain Interaction (DGBI) characterized by altered motility, visceral hypersensitivity, dysbiosis, and central nervous system processing abnormalities. Bloating is a challenging and distressing symptom that often persists despite standard pharmacological treatments.
The low FODMAP diet has been widely studied as a dietary approach to alleviate IBS symptoms. FODMAPs (Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols) are poorly absorbed short-chain carbohydrates that increase osmolarity, promote intestinal gas production, and alter gut microbiota, leading to bloating and discomfort. Although studies support the effectiveness of the low FODMAP diet, existing research lacks controlled, blinded trials assessing its impact on bloating-specific symptoms and related physiological markers.
This study addresses these gaps by using a double-blind, controlled design with rigorously standardized meals containing well-defined FODMAP content. It will assess clinical outcomes, gut microbiota composition, gas production, and metabolomic changes to elucidate the mechanisms underlying the diet's effects.
Study Design This is a randomized, double-blind, controlled trial conducted at a single center. Participants will be assigned to receive either a low FODMAP or a high FODMAP diet for two weeks.
Participants:
研究设计
- 研究类型
- Interventional
- 分配方式
- Randomized
- 干预模型
- Parallel
- 主要目的
- Treatment
- 盲法
- Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
盲法说明
This study employs a double-blind design, where both participants and study personnel (including investigators, dietitians, and outcome assessors) are blinded to dietary assignments. Meals in both groups are designed to have identical appearance, texture, and calorie content, differing only in FODMAP composition to maintain blinding. Food preparation staff, who are not involved in data collection or patient interaction, will be the only personnel aware of group assignments. The randomization sequence is generated by an independent researcher who does not participate in data analysis or outcome assessment. Blinded data analysis will be conducted to prevent bias. Participants will be instructed not to discuss meal characteristics to preserve masking. This ensures objective assessment of dietary effects on bloating, microbiota composition, gas production, and metabolic profiles.
入排标准
- 年龄范围
- 18 Years 至 —（Adult, Older Adult）
- 性别
- All
- 接受健康志愿者
- 否
入选标准
- •Age ≥18 years
- •Diagnosed with Irritable Bowel Syndrome (IBS) or Functional Constipation (FC) based on Rome IV criteria
- •Persistent bloating affecting daily life, with a bloating VAS score ≥4
- •Stable bowel habits with Bristol Stool Form Scale (BSFS) type 3-5
- •History of prior treatment with antispasmodics and/or prokinetics (allowed if dose remains stable)
- •Able to comply with dietary intervention and study procedures
排除标准
- •Prior gastrointestinal surgery (except appendectomy or cholecystectomy)
- •Use of antibiotics, proton pump inhibitors (PPIs), probiotics, NSAIDs, lactulose, or metformin within the past 4 weeks
- •Presence of systemic diseases affecting gut microbiota (e.g., liver cirrhosis, uncontrolled diabetes, end-stage renal disease, obesity, cancer, psychiatric disorders)
- •Inability to consume study meals or follow dietary restrictions
研究组 & 干预措施
Low FODMAP Diet
Participants will follow a low FODMAP diet for two weeks, consuming standardized meals with minimal fermentable carbohydrates. Meals match the high FODMAP diet in appearance to maintain blinding.
干预措施: Low FODMAP Diet (Other)
High FODMAP Diet
Participants will follow a high FODMAP diet for two weeks, consuming standardized meals with high fermentable carbohydrates. Meals match the low FODMAP diet in appearance to maintain blinding.
干预措施: High FODMAP Diet (Other)
结局指标
主要结局
Change in Bloating Severity (VAS)
时间窗: Baseline to 2 weeks (End of Intervention)
The primary outcome is the change in bloating severity, measured using the Visual Analog Scale (VAS). The VAS score ranges from 0 (no bloating) to 10 (severe bloating), with higher scores indicating worse bloating symptoms. Participants will record daily bloating scores throughout the intervention period. The proportion of participants achieving a ≥30% decrease in bloating severity from baseline will be analyzed.
次要结局
- Reduction in Global IBS Symptoms (IBS-SSS)(Baseline to 2 weeks)
- Change in Abdominal Pain (VAS)(Baseline to 2 weeks)
- Change in Stool Frequency and Consistency(Baseline to 2 weeks)
- Changes in Gut Microbiota Composition(Baseline to 2 weeks)
- Change in Hydrogen Gas Production (Lactulose Breath Test)(Baseline to 2 weeks)
- Change in Methane Gas Production (Lactulose Breath Test)(Baseline to 2 weeks)
- Use of Rescue Medications(Baseline to 2 weeks)
- Change in Psychological Symptoms (DASS-21)(Baseline to 2 weeks)
- Change in Quality of Life (IBS-QoL / PAC-QoL)(Baseline to 2 weeks)
- Patient Satisfaction with Treatment(Baseline to 2 weeks)
- Change in Patient-Reported Constipation Symptoms (PAC-SYM)(Baseline to 2 weeks)
- Change in Short-Chain Fatty Acids (SCFAs) Levels(Baseline to 2 weeks)
- Change in Urine Histamine Levels(Baseline to 2 weeks)
- Change in Constipation-Specific Quality of Life (PAC-QoL)(Baseline to 2 weeks)
- Change in Urine Azelaic Acid Levels(Baseline to 2 weeks)
研究者
Watcharasak Chotiyaputta
Associate Professor
Mahidol University