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Using Breath Tests to Study Gut Sulfur Changes During Dietary Therapy (Sulfur-UC)

5. juni 2026 oppdatert av: Natasha Haskey, University of British Columbia

Sulfur on the Breath: Using Breath Biomarkers to Monitor Gut Microbial Sulfur Metabolism During Elemental and Reduced Sulfur Dietary Therapy

This study aims to test whether a short liquid-based diet, followed by a low-sulfur eating plan, is safe, manageable, and helpful for people with mild to moderate ulcerative colitis. Investigators want to see if this approach can improve gut health, lower inflammation, and reduce symptoms. Investigators will also test breath samples as an easy, non-invasive way to track gut bacteria activity and disease changes. Investigators believe this diet plan can reduce harmful gut bacteria that produce irritating sulfur compounds, leading to better gut health and measurable improvements that can be detected through breath testing.

Studieoversikt

Status

Har ikke rekruttert ennå

Forhold

Intervensjon / Behandling

Detaljert beskrivelse

Purpose To determine whether a short-term elemental diet followed by a reduced sulfur diet is a safe, tolerable, and effective non-pharmacologic strategy to improve clinical outcomes, reduce inflammation, and beneficially modulate the gut microbiome in adults with mild-to-moderate ulcerative colitis. A secondary purpose is to validate breath-based biomarkers as non-invasive tools to monitor sulfur metabolism and disease activity. Breath biomarkers include volatile organic compounds (VOCs) and exhaled breath condensate (EBC) to assess sulfur-related metabolites.

Hypothesis A 2-week elemental diet followed by a 10-week reduced sulfur diet will reduce intestinal inflammation and improve clinical outcomes by shifting the gut microbiome away from pro-inflammatory, sulfur-metabolizing bacteria, resulting in reduced sulfur metabolite production detectable through exhaled volatile organic compounds and exhaled breath condensate.

Justification Despite advances in biologic therapies, many UC patients fail to achieve sustained remission, and current treatments do not address upstream drivers such as diet-microbiome interactions. Elemental diets have demonstrated efficacy in Crohn's disease but remain understudied in UC. Emerging evidence links dietary sulfur, microbial sulfur metabolism, and toxic metabolites to UC pathogenesis. This study addresses critical gaps by testing a feasible dietary intervention and validating non-invasive breath biomarkers for real-time disease monitoring and precision nutrition.

Objectives

  • Evaluate the clinical efficacy, safety, and feasibility of an elemental diet followed by an reduced sulfur diet.
  • Characterize changes in gut microbiome composition, inflammatory markers, and sulfur-related metabolic outputs.
  • Validate breath-based volatile organic compounds and exhaled breath condensate as biomarkers of sulfur metabolism and treatment response.
  • Identify microbial and metabolic signatures predictive of dietary response.

Research Design A prospective, randomized, controlled trial in adults with mild-to-moderate UC. All participants complete a 2-week elemental diet, followed by randomization (2:1) to either a reduced sulfur diet group (intervention group) or return to habitual diet group (control group) for 10 weeks. Clinical indices, inflammatory biomarkers, stool microbiome profiles and breath samples are collected longitudinally. The initial 2-week elemental diet is applied uniformly to standardize baseline microbial and metabolic conditions prior to randomization and does not replace or delay clinical care decisions.

Statistical Analysis Primary outcomes will be assessed using within- and between-group comparisons of clinical and biochemical response at week 12. Microbiome and metabolomic data will be analyzed using multivariate and differential abundance methods. Correlations between breath biomarkers, microbiome features, and clinical outcomes will assess sensitivity and specificity.

Studietype

Intervensjonell

Registrering (Antatt)

45

Fase

  • Ikke aktuelt

Kontakter og plasseringer

Denne delen inneholder kontaktinformasjon for de som utfører studien, og informasjon om hvor denne studien blir utført.

Studiekontakt

Studiesteder

  • Canada
    • British Columbia
      • Kelowna, British Columbia, Canada, V1V 1V7
        • University of British Columbia-Okanagan
        • Ta kontakt med:
        • Hovedetterforsker:
          • Natasha Haskey, RD, PhD

Deltakelseskriterier

Forskere ser etter personer som passer til en bestemt beskrivelse, kalt kvalifikasjonskriterier. Noen eksempler på disse kriteriene er en persons generelle helsetilstand eller tidligere behandlinger.

Kvalifikasjonskriterier

Alder som er kvalifisert for studier

  • Voksen
  • Eldre voksen

Tar imot friske frivillige

Nei

Beskrivelse

Inclusion Criteria:

  • Age 19-70 years.

    =Diagnosis of mild-to-moderate ulcerative colitis, defined by a partial Mayo score (pMayo) of 2-7.

  • Evidence of active inflammation at enrollment, defined as:
  • C-reactive protein (CRP) > 5 mg/L; or
  • Fecal calprotectin (FCP) > 200 µg/g.
  • Receiving stable medical therapy for ulcerative colitis for at least 8 weeks prior to enrollment.
  • No corticosteroid use at the time of recruitment.
  • Under consideration by the treating physician for treatment escalation or biologic switch due to inadequate response to current therapy.

Exclusion Criteria:

  • Partial Mayo score (pMayo) > 7.
  • Pregnant or breastfeeding.
  • Body mass index (BMI) < 18 kg/m².
  • History of an eating disorder.
  • Severe psychiatric disorder.
  • Severe medical conditions, including:
  • Active cancer;
  • Significant cardiovascular disease;
  • Diabetes mellitus; or
  • Severe food allergies.
  • Known allergy or intolerance to corn, dextrose, or maltodextrin.
  • Antibiotic use within 3 months prior to enrollment.
  • Probiotic use within 3 months prior to enrollment.
  • Use of herbal anti-inflammatory supplements during the study period, including but not limited to:
  • Serrapeptidase;
  • Curcumin;
  • Boswellia; or
  • Bromelain.
  • History of major gastrointestinal surgery, including:
  • Ostomy;
  • Total colectomy; or
  • Short bowel syndrome.
  • Inability or unwillingness to comply with study procedures, including anticipated travel or other commitments that may interfere with participation.

Studieplan

Denne delen gir detaljer om studieplanen, inkludert hvordan studien er utformet og hva studien måler.

Hvordan er studiet utformet?

Designdetaljer

  • Primært formål: Behandling
  • Tildeling: Randomisert
  • Intervensjonsmodell: Parallell tildeling
  • Masking: Enkelt

Våpen og intervensjoner

Deltakergruppe / Arm
Intervensjon / Behandling
Eksperimentell: Reduced Sulfur Diet
Participants will consume a novel elemental formula (mBiota Elemental, Good LFE, Santa Monica, CA) as their sole source of nutrition for two weeks. followed by a 10-week reduced sulfur diet. The reduced sulfur diet is designed to limit dietary sources of sulfur-containing compounds that may contribute to hydrogen sulfide production by the gut microbiota.
Kosttilskudd: Elemental formula (mBiota Elemental, Good LFE, Santa Monica, CA)
Elemental liquid diets (EDs) are a subset of Exclusive Enteral Nutrition (EEN). Similar to EEN, they are nutritionally complete formulas, but differ in that they consist of free amino acids, monosaccharides, and fatty acids instead of whole, intact macronutrients, which are designed for optimal digestibility and to minimize antigenicity. EDs have been shown to reduce immune activation, favourably modulate the microbiota, suppress proinflammatory cytokines, support epithelial repair, and exclude common dietary additives that may provoke inflammation.
Atferdsmessig: Reduced Sulfur diet
This diet excludes high sulfur foods (e.g., red meat, seafood, eggs), cruciferous vegetables, dried fruits, and fermented beverages. It also accounts for sulfate intake from drinking water and processed food additives.
Aktiv komparator: Habitual Diet
Participants will complete a 2-week elemental diet intervention followed by a 10-week habitual diet. Participants will be instructed to resume and maintain their usual dietary intake without specific sulfur-restriction recommendations.
Kosttilskudd: Elemental formula (mBiota Elemental, Good LFE, Santa Monica, CA)
Elemental liquid diets (EDs) are a subset of Exclusive Enteral Nutrition (EEN). Similar to EEN, they are nutritionally complete formulas, but differ in that they consist of free amino acids, monosaccharides, and fatty acids instead of whole, intact macronutrients, which are designed for optimal digestibility and to minimize antigenicity. EDs have been shown to reduce immune activation, favourably modulate the microbiota, suppress proinflammatory cytokines, support epithelial repair, and exclude common dietary additives that may provoke inflammation.
Atferdsmessig: Habitual Diet
Participants randomized to the comparator group will continue their usual dietary intake for 10 weeks without specific dietary restrictions.

Hva måler studien?

Primære resultatmål

Resultatmål
Tiltaksbeskrivelse
Tidsramme
Composite clinical and biochemical response
Tidsramme: Baseline, Week 2 and week 12
Composite clinical and biochemical response at week 12, defined as >30% and >1-point reduction in pMayo score from baseline, plus rectal bleeding subscore decrease of >1 or an absolute subscore <1, with fecal calprotectin <250 μg/g and CRP <5 mg/L.
Baseline, Week 2 and week 12

Sekundære resultatmål

Resultatmål
Tiltaksbeskrivelse
Tidsramme
Stool Biomarkers
Tidsramme: Baseline, week 2 and week 12
fecal calprotectin, shotgun metagenomics (microbiome composition, sulfur metabolizing bacteria), and targeted metabolomics (e.g., hydrogen sulfide, thiosulfate)
Baseline, week 2 and week 12
C-Reactive Protein (CRP) concentration
Tidsramme: Baseline, week 2 and week 12
Serum CRP concentration will be measured to assess systemic inflammation.
Baseline, week 2 and week 12
Complete Blood Count (CBC) parameters
Tidsramme: Baseline, week 2 and week 12
CBC parameters, including hemoglobin, white blood cell count, platelet count, and differential counts, will be measured.
Baseline, week 2 and week 12
Serum inflammatory biomarker concentrations
Tidsramme: Baseline, week 2 and week 12
Serum concentrations of IL-6, TNF-α, MCP-1, and LBP will be measured individually and reported separately.
Baseline, week 2 and week 12
Breath Biomarkers
Tidsramme: Baseline, week 2 and week 12
Volatile Organic Compounds (VOCs) and exhaled breath condensate (EBC) to assess sulfur-containing metabolites and host-microbiota interactions
Baseline, week 2 and week 12
Adherence to the Elemental Diet and Reduced Sulfur Diet Intervention
Tidsramme: Baseline, week 2 and week 12

Adherence to the ED intervention will be assessed using a modified Medication Adherence Report Scale questionnaire at each visit, as well as through compliance phone calls and food diaries. Poor adherence will be defined as meeting at least one of the following three criteria:

  1. intolerance, indicated by discontinuation of dietary therapy due to the patient's refusal to continue; or
  2. low adherence scores (score of 0-1) reported on the modified Medication Adherence Report Scale; and
  3. collect the empty mBiota containers as a measure of adherence. Adherence to the RS diet will be assessed through food recalls collected via ASA-24.

Adverse events (AEs) will be systematically collected throughout the study using a combination of participant self-reporting, scheduled assessments, and clinical monitoring.
Baseline, week 2 and week 12
Change in Quality of Life
Tidsramme: Baseline, week 2 and week 12
Health-related quality of life will be measured using the 12-item short form-12 (SF-12). The SF-12 comprises two components: physical health and mental health. Scores range from 0 to 100, where 0 indicates the lowest level of health and 100 the highest.
Baseline, week 2 and week 12
Change in Anxiety
Tidsramme: Baseline, week 2 and week 12
Anxiety will be assessed by the GAD-7 (Generalized Anxiety Disorder-7). It is a self-reported screening tool used to measure the severity of generalized anxiety disorder (GAD) symptoms over the past two weeks. The total score ranges from 0 to 21. A score of 10 or higher typically indicates clinically significant anxiety and suggests the need for further evaluation or intervention..
Baseline, week 2 and week 12
Change in Depression
Tidsramme: Baseline, week 2 and week 12
Depression levels will be assessed by PHQ-8 (Patient Health Questionnaire-8). It is a widely used self-report screening tool for assessing the severity of depressive symptoms over the past two weeks. The total score is the sum of all item responses, ranging from 0 to 24. A score of 10 or higher indicates the presence of clinically significant depressive symptoms and suggests the need for further evaluation or intervention.
Baseline, week 2 and week 12
Change in Weight
Tidsramme: Baseline, week 2 and week 12
Body weight will be measured in kilograms (kg)
Baseline, week 2 and week 12
Change in Body Mass Index (BMI)
Tidsramme: Baseline, week 2 and week 12
BMI will be calculated as weight (kg) divided by height squared (m²).
Baseline, week 2 and week 12

Samarbeidspartnere og etterforskere

Det er her du vil finne personer og organisasjoner som er involvert i denne studien.

Sponsor

University of British Columbia

Samarbeidspartnere

University of Calgary

Etterforskere

  • Hovedetterforsker: Natasha Haskey, RD, PhD, University of British Columbia

Studierekorddatoer

Disse datoene sporer fremdriften for innsending av studieposter og sammendragsresultater til ClinicalTrials.gov. Studieposter og rapporterte resultater gjennomgås av National Library of Medicine (NLM) for å sikre at de oppfyller spesifikke kvalitetskontrollstandarder før de legges ut på det offentlige nettstedet.

Studer hoveddatoer

Studiestart (Antatt)

1. juni 2026

Primær fullføring (Antatt)

1. mars 2029

Studiet fullført (Antatt)

31. desember 2029

Datoer for studieregistrering

Først innsendt

29. mai 2026

Først innsendt som oppfylte QC-kriteriene

5. juni 2026

Først lagt ut (Faktiske)

11. juni 2026

Oppdateringer av studieposter

Sist oppdatering lagt ut (Faktiske)

11. juni 2026

Siste oppdatering sendt inn som oppfylte QC-kriteriene

5. juni 2026

Sist bekreftet

1. juni 2026

Mer informasjon

Begreper knyttet til denne studien

Nøkkelord

Ytterligere relevante MeSH-vilkår

Andre studie-ID-numre

  • H26-00017
  • POP25-11968 (Annet stipend/finansieringsnummer: Weston Family Foundation)

Plan for individuelle deltakerdata (IPD)

Planlegger du å dele individuelle deltakerdata (IPD)?

JA

IPD-planbeskrivelse

All IPD used in the results of the publication will be shared

Tilgangskriterier for IPD-deling

A proposal for planned analyses must be submitted to the PI's of this research.

IPD-deling Støtteinformasjonstype

  • STUDY_PROTOCOL
  • SEVJE
  • ICF
  • ANALYTIC_CODE
  • CSR

Legemiddel- og utstyrsinformasjon, studiedokumenter

Studerer et amerikansk FDA-regulert medikamentprodukt

Nei

Studerer et amerikansk FDA-regulert enhetsprodukt

Nei

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