Low FODMAPs Diet vs. Specific Dietary Advice in Patients With IBS Diarrheal Variant (DIETSINIBS)

Effects of a Diet Low in Fructose, Oligosaccharides, Disaccharides, Monosaccharides, Alcohols and Polyols in Patients With Irritable Bowel Syndrome Diarrheal Variant Respect to Dietary Advice: Randomized, Single Blind Clinical Trial.

A reduced content of FODMAPs (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) in the diet may be beneficial for patients with IBS diarrheal variant, but so far few randomized trials have reported data in favor of the effective therapeutic superiority of a low-FODMAPs diet compared to specific IBS dietary advice. On this basis, the present study is aimed, in a multidisciplinary perspective, at investigating possible changes in the symptom profile and intestinal permeability, GI peptides concentrations, metabolic and lipidomic profiles induced by these different diets in patients with IBS diarrheal variant.

Study Overview

• Status: Completed
• Conditions: Irritable Bowel Syndrome
• Intervention / Treatment: Dietary supplement: Diet low in FODMAPs; Dietary supplement: Specific dietary advice for IBS

Detailed Description

Irritable Bowel Syndrome (IBS) is a functional gastrointestinal disease (GI) affecting 10% -20% of the population and is composed of abdominal pain/discomfort, in combination with alterations of the stool habit. This is a functional disorder prevalent in Italy with double percentages in urban areas (13.7%) compared to rural ones (5.9%). IBS is still one of the main reasons for patients to seek for gastroenterological advice. The diagnosis of IBS is mainly based on the evaluation of symptom profiles by using different scales of assessment and also taking into account non-GI symptoms (e.g. insomnia, anxiety, and depression), as well as the characteristics of the stools. IBS is classified in different subtypes, namely: IBS diarrheal variant (IBS-D), IBS with constipation (IBS-C), IBS mixed variant (IBS-M) and non-classifiable. The pathophysiology is only partially understood and an abnormal motility, together with alterations in gut-brain communication, a low-grade inflammation, and psychosocial factors, have been variously involved. On the other hand, the therapeutic choices are still scarce. The majority of IBS subjects believe that some foods are responsible for their symptoms, tending to exclude them without, however, compromising their nutritional status [14]. Many dietary approaches have been proposed, but only a few controlled studies have been performed in this field. Recent evidence suggests that the intake of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols (FODMAPs) may trigger GI symptoms in patients with IBS. These carbohydrates are poorly absorbed in the small intestine and can pass intact in the colon, where they increase the endoluminal water through the osmotic activity and induce the production of gas due to their fermentation by intestinal bacterial flora. This, in turn, can cause abdominal distension and diarrhea. Data in the literature suggest that a diet with a reduced content in FODMAPs may be beneficial for patients with IBS and diarrhea, but so far few randomized trials have reported data in favor of the effective superiority of a low-FODMAPs diet compared to the specific dietary advice for patients with IBS. On this basis, the present study is aimed at comparing these two diets in a randomized, single-blind clinical trial in IBS patients with diarrhea.

• Study Type: Interventional
• Enrollment (Actual): 62
• Phase: Not Applicable

Contacts and Locations

Study Locations

• Italy
  • Bari
    • Castellana Grotte, Bari, Italy, 70013
      • Irccs Saverio de Bellis

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 14 years to 61 years (Adult, Older Adult)
• Accepts Healthy Volunteers: No
• Genders Eligible for Study: All

Description

Inclusion Criteria:

• Rome IV criteria for IBS diarrhea variant (IBS-D).
• Low-lactose diet is allowed, provided that patients agree to keep this intake constant throughout the study period, except in the case of randomization in the treatment arm with a low-FODMAPs diet.
• The use of probiotic products is permitted, and patients who consume probiotic products must be instructed to continue taking the same amount previously taken throughout the study period.
• The drugs used to treat IBS, including antidepressants, will be admitted provided they are used regularly and have a stable dosage for at least one month prior to inclusion in the study.
• Patients must be willing to change their current diet to participate in the study for the whole study period.

Exclusion Criteria:

• Serious cardiac, hepatic, neurological or psychiatric diseases.
• GI diseases other than IBS (e.g., inflammatory bowel disease, celiac disease) that could explain current symptoms.
• Patients who previously had a low-content diet of particular substances (for example, low FODMAPs content, vegan diet, gluten-free diet). - This last category of subjects will be able to return to the study provided they suspend the gluten-free diet until thes symptoms reappear.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Single

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Diet low in FODMAPs; Diet low in FODMAPs (diet A) during 12 weeks (with intermediate nutritional checks every 4 weeks) before returning to the final study visit.	Dietary supplement: Diet low in FODMAPs; A strict restriction of all high FODMAP foods for the time of observation. All these foods will be identified by appropriate nutritional visits and alternatives will be suggested to ensure the diet is nutritionally adequate.
Active Comparator: Specific dietary advice for IBS; Dietary advice for IBS (diet B) during 12 weeks (with intermediate nutritional checks every 4 weeks) before returning to the final study visit.	Dietary supplement: Specific dietary advice for IBS; Dietary recommendations such as limitation of alcohol, spicy food and fatty foods, caffeine, carbonated drinks; avoidance of chewing gums and sweeteners containing polyols; small and frequent meals; avoidance of stressful conditions and eating slowly.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in the total score of the irritable bowel syndrome - severity scoring system (IBS-SSS) 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), leading to a total possible score of 500. The primary outcome corresponds to a change in the total score of the IBS-SSS questionnaire at the end of the treatment period compared to baseline, and the proportion of patients who will achieve a difference in the total symptom score of IBS-SSS ≥50 after diet. Such difference is considered a significant clinical improvement.	Time frame: Before the start of the study (time 0) and after 90 days of treatment (time 90).

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in the score of the single symptom items of the irritable bowel syndrome - severity scoring system (IBS-SSS) 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). The secondary outcome is the measure of the effects of the dietary interventions on the individual symptom items score of IBS-SSS, as well as on the characteristics of the stool habit through the administration of the diaries.	Time frame: Before the start of the study (time 0) and after 90 days of treatment (time 90).
Change in the intestinal permeabily evaluation	For the evaluation of intestinal permeability, a test solution is prepared with 40 g sucrose (Su), 10 g lactulose (La) and 5 g mannitol (Ma) dissolved in 100 ml of water. The participants drink the test solution in the morning after an overnight fast and all urine samples are collected for the subsequent 5 h. Urine samples were stored at -80°C until analysis. The detection and measurement of the three sugar probes, Su, La, and Ma, in urine are performed by high-performance anion exchange chromatography coupled with pulsed amperometric detection.	Time frame: Before the start of the study (time 0) and after 90 days of treatment (time 90).
Change in the GI peptide concentrations	To evaluate GI peptide, blood samples are collected in ice chilled tubes containing Aprotinin and EDTA. The separated plasma are stored at -70 °C until assay. Plasma levels of spexin, copeptin, meteorin, somatostatin and serotonin, are measured by enzyme immunoassay technique using commercial kits before and after the dietary interventions	Time frame: Before the start of the study (time 0) and after 90 days of treatment (time 90).
Change in the lipidomic profile.	To evaluate the lipidomic, profile blood samples are collected in vacutainer tubes containing ethylenediaminetetraacetic acid (EDTA). The erythrocytes are separated from the plasma by centrifugation, suspended in pure water, vortexed and subsequently centrifuged to isolate the membrane pellets. Lipid extraction and lipid transesterification to fatty acid methyl esters (FAMEs) are performed using an automated protocol. Phospholipidsare will be trans-esterified to FAMEs by treatment with a potassium hydroxide (KOH)/methyl alcohol (MeOH) solution and are extracted using n-hexane. Fatty acids quantification will be performed by using a gas chromatography equipment. Quantification of fatty acid methyl esters is performed using a mixture of standards. The amount of each fatty acid is calculated before and after the dietary interventions, as a percentage of the total fatty acid content (relative %).	Time frame: Before the start of the study (time 0) and after 90 days of treatment (time 90).

Collaborators and Investigators

• Sponsor: Azienda Ospedaliera Specializzata in Gastroenterologia Saverio de Bellis
• Investigators: Principal Investigator: Francesco Russo, National Institute for Digestive Diseases IRCCS " Saverio de Bellis"

Publications and helpful links

General Publications

• Lovell RM, Ford AC. Global prevalence of and risk factors for irritable bowel syndrome: a meta-analysis. Clin Gastroenterol Hepatol. 2012 Jul;10(7):712-721.e4. doi: 10.1016/j.cgh.2012.02.029. Epub 2012 Mar 15.
• Halmos EP, Power VA, Shepherd SJ, Gibson PR, Muir JG. A diet low in FODMAPs reduces symptoms of irritable bowel syndrome. Gastroenterology. 2014 Jan;146(1):67-75.e5. doi: 10.1053/j.gastro.2013.09.046. Epub 2013 Sep 25.
• Mearin Manrique F. Irritable bowel syndrome (IBS) subtypes: Nothing resembles less an IBS than another IBS. Rev Esp Enferm Dig. 2016 Feb;108(2):57-8. doi: 10.17235/reed.2016.4195/2016.
• Gonzalez-Castro AM, Martinez C, Salvo-Romero E, Fortea M, Pardo-Camacho C, Perez-Berezo T, Alonso-Cotoner C, Santos J, Vicario M. Mucosal pathobiology and molecular signature of epithelial barrier dysfunction in the small intestine in irritable bowel syndrome. J Gastroenterol Hepatol. 2017 Jan;32(1):53-63. doi: 10.1111/jgh.13417.
• Mazzawi T, El-Salhy M. Changes in duodenal enteroendocrine cells in patients with irritable bowel syndrome following dietary guidance. Exp Biol Med (Maywood). 2017 Jul;242(13):1355-1362. doi: 10.1177/1535370217699537. Epub 2017 Mar 17.
• Shepherd SJ, Lomer MC, Gibson PR. Short-chain carbohydrates and functional gastrointestinal disorders. Am J Gastroenterol. 2013 May;108(5):707-17. doi: 10.1038/ajg.2013.96. Epub 2013 Apr 16.
• McKee AM, Prior A, Whorwell PJ. Exclusion diets in irritable bowel syndrome: are they worthwhile? J Clin Gastroenterol. 1987 Oct;9(5):526-8. doi: 10.1097/00004836-198710000-00007.
• Prospero L, Riezzo G, Linsalata M, Orlando A, D'Attoma B, Di Masi M, Martulli M, Russo F. Somatization in patients with predominant diarrhoea irritable bowel syndrome: the role of the intestinal barrier function and integrity. BMC Gastroenterol. 2021 May 22;21(1):235. doi: 10.1186/s12876-021-01820-7.

Study record dates

Study Major Dates

• Study Start (Actual): February 5, 2018
• Primary Completion (Actual): July 30, 2019
• Study Completion (Actual): December 31, 2020

Study Registration Dates

• First Submitted: January 22, 2018
• First Submitted That Met QC Criteria: January 30, 2018
• First Posted (Actual): February 6, 2018

Study Record Updates

• Last Update Posted (Actual): March 22, 2022
• Last Update Submitted That Met QC Criteria: March 21, 2022
• Last Verified: March 1, 2022

More Information

Terms related to this study

• Keywords: Microbiome; Gastrointestinal symptoms; Irritable bowel syndrome; Intestinal permeability; Gastrointestinal peptides; FODMAPs; Dietary advice; Lipidomic profile
• Additional Relevant MeSH Terms: Digestive System Diseases; Pathologic Processes; Disease; Gastrointestinal Diseases; Colonic Diseases, Functional; Colonic Diseases; Intestinal Diseases; Syndrome; Irritable Bowel Syndrome
• Other Study ID Numbers: RC2018B

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: No

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No