Irritable Bowel Syndrome (IBS) is a common functional bowel disorder characterized by absence of any organic cause. The vast majority of patients associate their symptoms with specific food consumption, creating the need for developing a new therapeutic approach based on altering the dietary habits. The aim of the study focuses in the comparison of the efficacy of two dietary patterns, the adjusted to the Mediterranean Diet Low FODMAP Diet (MED-LFD) and the nutritional guidelines of the British National Institute for Health and Care Excellence (NICE) Managing IBS.
Irritable Bowel Syndrome (IBS) is a functional bowel disorder. Patients associate their symptoms with specific foods consumption, creating the need for developing a new therapeutic approach based on altering the dietary intake of these patients. Low FODMAP Diet is often used as a first-line treatment based on observations showing that short-chain carbohydrates are not adequately absorbed in the small intestine and exacerbate the symptoms of IBS. Additionally, the Mediterranean diet is a cultural heritage representative of all the countries surrounded by the Mediterranean Sea, described as a diet rich in herbal foods (cereals, fruits, vegetables, legumes, nuts, olives), with olive oil as the main consumption of fats, high to moderate consumption of fish and seafood, moderate consumption of eggs, poultry, dairy products and alcohol and low consumption of red meat. On the other hand, the nutritional recommendations of British National Institute for Health and Care Excellence (NICE) managing IBS were created on the grounds of systematic reviews and are based on dietary and lifestyle modifications about caffeine, alcohol, fizzy drinks, fiber, resistant starch, fruits, sorbitol, oat and linseed consumption, meal patterns, probiotics and physical activity. The direct aim of the study is to compare the efficacy of two dietary patterns, the MED-LFD and the nutritional recommendations of NICE managing IBS. Efficacy will be assessed based on the severity of symptoms. Additionally, possible improvements in quality of life and relief of symptoms between the two groups will be evaluated. Finally, the collected fecal samples will be used to assess the effect of each intervention on gut microbiota. The sample was calculated to 108 participants with prespecified statistical power 80%, level of significance α=0.05 and 10% adjustment for non-compliance in each group to detect an increase in the primary outcome measure (standard deviation of outcome=60). The above hypothesis of the means was based in the meta-analysis of Peter Varju, et al. 2017. Patients will be recruited by the Department of Clinical Nutrition, Attikon University General Hospital, where the nutritional intervention will be carried out.
Study Type
All participants of this group at phase 1 (elimination phase), will initially follow the Med- LFD (2-6 weeks). At phase 2 (reintroduction phase), patients will gradually reintroduce foods rich in FODMAPs (6-8 weeks) and test their tolerance. At phase 3 (maintenance phase), following the reintroduction of foods rich in FODMAPs, patients will follow an individualized diet based on their personal tolerance (a combination of high and low FODMAPs).
All participants of this group will be informed to follow a diet based on the nutritional guidelines of the British National Institute for Health and Care Excellence (NICE) for Managing IBS for 4 weeks.
Attikon University General Hospital
Athens, Greece
Change of symptoms severity pre and post intervention using a specialized questionnaire.
IBS- SSS contains 5 specific questions with instructions on how to score them. Each of the five questions (pain severity, pain frequency, abdominal distension severity, bowel movement satisfaction, quality of life) ranges from 0 to a maximum score of 100 using a visual analog scale (VAS) with total scores ranging from 0 to 500, with higher scores indicating more severe symptoms. Subjects can be categorized as having mild (75-175), moderate (175-300), or severe (\>300) IBS. A decrease of 50 points is associated with a clinically meaningful improvement.
Time frame: Baseline, 4 - 8 weeks and 6 months post intervention
Assessment of IBS related quality of life with a specialized questionnaire pre and post intervention between groups.
IBS-QOL - a measure that assesses the degree to which IBS interfered with quality of life over the past 30 days. It is a self-report quality of life measure, which includes domains such as dysphoria, interference with activity, body image, health worry, food avoidance, social relation, sexual and relationship issues. Each of them is rated based on the Likert scale from 1 to 5, the higher the score the lower the quality of life is. The overall score ranges between 34 - 170. A decrease of 10 points or more is a significant improvement.
Time frame: Baseline, 4 - 8 weeks and 6 months post intervention
Assessment of general quality of life pre and post intervention between groups
12-Item Short Form Survey (SF-12) is a 12-item questionnaire used to assess generic health outcomes from the patient's perspective, covering the eight domains of health outcomes: physical functioning, role-physical, bodily pain, general health, vitality, social functioning, role-emotional \& mental health. The items are weighted and summed to provide physical and mental health scores (PCS and MCS). The two composite scores are computed using the scores on the questions that range from 0 to 100, with higher score indicating better health.
Time frame: Baseline, 4 - 8 weeks and 6 months post intervention
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INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
SUPPORTIVE_CARE
Masking
SINGLE
Enrollment
108
Adequate relief of symptoms after the intervention.
Adequate relief (IBS-AR) is a single item questionnaire of pain and discomfort. It poses the question "Over the past week have you had adequate relief of your IBS symptoms?", with a positive or negative answer. Adequate relief is defined as 50% positive answers within the study period, for the purposes of the trial.
Time frame: Once per week
Assessment of symptoms burden in general pre and post intervention.
The GSRS questionnaire was originally developed for dyspeptic patients but was later validated in patients with IBS. The GSRS is a 15-item questionnaire designed to assess common gastrointestinal symptoms. The questionnaire has five subscales, reflux, diarrhea, constipation, indigestion, and abdominal pain, with subscale scores ranging from 1 (no discomfort) to 7 (severe discomfort). Higher scores represent higher symptom burden.
Time frame: Baseline, 4 - 8 weeks and 6 months post intervention
Assessment of anxiety and depression disorders pre and post intervention.
The Hospital Anxiety and Depression Scale (HADS) questionnaire is used for the assessment of anxiety and depression symptoms. It's a 14-item scale with seven items for each subscale, anxiety (HADS-A) and depression (HADS-D). Each item is scored on a response scale with four alternatives, ranging between 0 and 3. The total score is the sum of the 14 items, and for each subscale the score is the sum of the respective seven items (ranging from 0-21). A final score of 0-7 on each scale indicates that the patient has no symptoms, a score of 8-10 indicates mild symptoms while a score ≥11 indicates severe symptoms of anxiety and depressive disorders.
Time frame: Baseline, 4 - 8 weeks and 6 months post intervention
Evaluation of the effect of interventions on gut microbiota composition between groups.
Fecal samples will be collected from each participant and stored at -80°C.
Time frame: Baseline, 2 weeks and 6 months post intervention