An interventional study of Probiotic and Low-FODMAP Diet in Autism Spectrum Disorder and Functional Gastrointestinal Disorders, sponsored by Marmara University Pendik Training and Research Hospital. Completed at 1 site in Turkey (Türkiye). Open to participants aged 6 Years to 12 Years. Per ClinicalTrials.gov, last updated 2025-07-25.
Sponsored by Marmara University Pendik Training and Research Hospital · Not applicable, Interventional, and Treatment
The goal of this clinical trial was to evaluate whether a low-FODMAP diet and probiotic supplements could reduce gastrointestinal (GI) symptoms and behavior problems in children with autism spectrum disorder (ASD) who also experienced GI issues. The main questions it aimed to answer were:
Did a low-FODMAP diet and/or probiotics improve GI symptoms such as constipation, diarrhea, and abdominal pain?
Did these interventions help reduce behavior problems such as irritability, lethargy, stereotypy, hyperactivity, and speech disorder ?
Researchers compared two groups:
This comparison aimed to determine whether the combination of diet and probiotics had greater benefits than probiotics alone.
Participants:
Took the assigned intervention(s) for 4 weeks
Provided stool samples for gut microbiota analysis
Completed assessments of GI symptoms and behavior using validated questionnaires
This randomized, controlled, parallel-group clinical trial aimed to investigate the effects of a low-FODMAP diet and multi-strain probiotic supplementation on gastrointestinal (GI) symptoms, behavioral problems, and gut microbiota composition in children with Autism Spectrum Disorder (ASD) who presented with concurrent GI complaints.
Children aged 6 to 12 years with clinically diagnosed ASD and GI symptoms were recruited. A total of 16 participants were randomly assigned into two equal groups (n=8 per group). One group received a probiotic supplement containing four bacterial strains daily for 4 weeks, while the second group received the same probiotic supplement in combination with a low-FODMAP diet over the same period. The randomization was stratified and allocation was blinded to the data analysts.
Interventions Probiotic group: A commercially available probiotic blend (containing Lactobacillus acidophilus, Bifidobacterium longum, Lactobacillus rhamnosus, and Saccharomyces boulardii) was administered once daily for 4 weeks.
Low-FODMAP + Probiotic group: In addition to the probiotic supplement, participants received individualized nutrition counseling and followed a standardized low-FODMAP diet protocol under dietitian supervision for 4 weeks.
Data Collection and Measures GI symptoms were assessed using the Pediatric Gastrointestinal Symptoms Questionnaire - Rome III Version (QPGS-RIII) and the Bristol Stool Scale (BSS).
Behavioral outcomes were evaluated using the Aberrant Behavior Checklist (ABC), focusing on subscales including irritability, lethargy-social withdrawal, stereotypy, hyperactivity, and inappropriate speech.
Dietary intake was recorded using 3-day food diaries to determine intake of daily FODMAP amount.
Microbiota composition was analyzed from fecal samples using 16S rRNA gene sequencing and LEfSe (Linear Discriminant Analysis Effect Size) for taxonomic biomarker discovery.
Quality Control and Data Validation All participants were monitored weekly to ensure adherence to interventions and assess adverse effects.
Dietary intake data were validated against food portion models and caregiver interviews.
Stool sample processing followed standardized protocols: DNA was extracted, amplified, and sequenced using Illumina platforms.
A pre-defined bioinformatics pipeline was used for quality filtering, taxonomic assignment, and alpha/beta diversity analysis.
Internal consistency checks and double data entry validation were applied to all behavioral and symptom questionnaires.
Statistical Analysis Statistical analysis was performed using SPSS v25 and R. Paired and independent-sample t-tests or Wilcoxon signed-rank tests were applied based on distribution normality. Microbiota diversity indices (Shannon, Simpson, Chao1) and taxonomic differences were compared across groups and time points. Spearman correlation analyses were used to explore associations between microbiota shifts and clinical parameters. A p-value of \<0.05 was considered statistically significant.
1,727 studies on the registry are indexed under Autism Spectrum Disorder; 504 are open to participants now.
This study's enrollment of 16 is below the median of 52 across 1,371 interventional studies indexed under Autism Spectrum Disorder.
Browse Autism Spectrum Disorder studies →Marmara University Pendik Training and Research Hospital is the lead sponsor of 32 studies on the registry; 13 are open to participants now.
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Exclusion Criteria:
Participants in this arm received the same probiotic supplement as the other group once daily for 4 weeks, in combination with a personalized low-FODMAP diet. The diet was planned and monitored by a registered dietitian to ensure compliance and nutritional adequacy.
Dietary Supplement: Probiotic · Other: Low-FODMAP Diet
Participants in this arm received a multi-strain probiotic supplement containing four bacterial strains (Lactobacillus acidophilus L1, Bifidobacterium longum LBL-01, Lactobacillus rhamnosus, and Saccharomyces boulardii) once daily for 4 weeks. No dietary restrictions or modifications were applied in this group.
Dietary Supplement: Probiotic
A probiotic supplement in capsule form containing 4 strains of microorganisms, with a total of 10 × 10⁹ CFU (colony-forming units) per capsule. The strain composition per capsule was: Lactobacillus acidophilus L1 - 2.9 × 10⁹ CFU, Bifidobacterium longum LBL-01 - 2.9 × 10⁹ CFU, Lactobacillus rhamnosus - 2.9 × 10⁹ CFU, Saccharomyces boulardii - 1.3 × 10⁹ CFU. Each participant in this arm took one capsule per day in the morning on a full stomach, for a duration of 4 weeks. No other dietary interventions were applied to this group. This probiotic supplement was chosen because the strains in its content are among the most frequently researched and known strains in terms of intestinal health. Additionally, it does not contain FOS or inulin due to FODMAP restriction. .
A structured low-FODMAP diet intervention designed to restrict intake of fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. The diet was individualized and monitored by a registered dietitian over a 4-week period to ensure adherence and nutritional adequacy.
Change in Aberrant Behavior Checklist (ABC) Irritability Subscale Score
Change in caregiver-reported irritability scores as measured by the Aberrant Behavior Checklist Irritability Subscale, a standardized behavioral rating scale.
Time frame: Baseline and after 4 weeks of intervention
Change in Aberrant Behavior Checklist (ABC) Hyperactivity Subscale Score
Change in hyperactivity scores, as assessed by the caregiver-completed Hyperactivity Subscale of the Aberrant Behavior Checklist (ABC), a standardized behavioral rating scale.
Time frame: Baseline and after 4 weeks of intervention
Change in Aberrant Behavior Checklist (ABC) Lethargy-Social Withdrawal Subscale Score
Change in lethargy-social withdrawal scores, as assessed by the caregiver-completed Lethargy-Social Withdrawal Subscale of the Aberrant Behavior Checklist (ABC), a standardized behavioral rating scale.
Time frame: Baseline and after 4 weeks of intervention
Change in Aberrant Behavior Checklist (ABC) Stereotypy Subscale Score
Change in stereotypy scores, as assessed by the caregiver-completed Stereotypy Subscale of the Aberrant Behavior Checklist (ABC), a standardized behavioral rating scale.
Time frame: Baseline and after 4 weeks of intervention
Change in Aberrant Behavior Checklist (ABC) Inappropriate Speech Subscale Score
Change in inappropriate speech scores, as assessed by the caregiver-completed Inappropriate Speech Subscale of the Aberrant Behavior Checklist (ABC), a standardized behavioral rating scale.
Time frame: Baseline and after 4 weeks of intervention
Change in Presence of Functional Gastrointestinal Symptoms as Measured by the QPGS-RIII
Change in the presence of any functional gastrointestinal symptoms as determined by caregiver responses to the Pediatric Gastrointestinal Symptoms Questionnaire - Rome III (QPGS-RIII), a validated diagnostic tool for functional gastrointestinal disorders in children.
Time frame: Baseline and after 4 weeks of intervention
Change in Gut Microbiota Alpha Diversity (Shannon Index)
Change in microbial alpha diversity of stool samples, assessed using 16S rRNA gene sequencing and expressed as the Shannon diversity index.
Time frame: Baseline and after 4 weeks of intervention
Change in Gut Microbiota Beta Diversity (UniFrac Analysis)
Change in microbial beta diversity of stool samples, assessed using 16S rRNA gene sequencing and analyzed with UniFrac distance metrics to evaluate differences in microbial community composition between samples.
Time frame: Baseline and after 4 weeks of intervention
Change in Relative Abundance of Specific Bacterial Genera
Change in the relative abundance (%) of key bacterial genera identified through 16S rRNA sequencing and LEfSe analysis.
Time frame: Baseline and after 4 weeks of intervention
Plan to share: Yes — All IPD that underlie results in a publication.
Supporting information: Study protocol, Icf
This study is completed, as verified in Jul 2025. You cannot join it, but the record below documents what was studied.
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Marmara University Pendik Training and Research Hospital