Lactose Intolerance, Adult TypeLINCT07424898
Lactose Intolerance and Intestinal Permability
An observational study of Lactose Intolerance, Adult Type and Intestinal Permability, run by Bezmialem Vakif University at 1 site in Turkey (Türkiye).
Trial summary
"This study evaluates the interplay between lactose intolerance, intestinal barrier function (zonulin), and intestinal inflammation (fecal calprotectin) in adults, aiming to clarify their independent contributions to symptom severity and quality of life." Read more about this study
- Who is it for?
- Ages 18 to 70 years
- Conditions the study is for
- Lactose Intolerance, Adult Type, Intestinal Permability, IBS (Irritable Bowel Syndrome)
- How many people
- 200 participants
- Where
- 1 siteTurkey (Türkiye)
- Study dates
- 10 Feb 2026to 15 Jun 2027
- How long will I take part?
- 12 Weeks
- Phase
- Observational
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 70 years
- All sexes
- No healthy volunteers
- Adult, Older adult
Study population: Patients with IBS, aged 18-70 years, both male and female, who meet the Rome-4 criteria, were included in this study. They were recruited from the Gastroenterology outpatient clinic of Bezmialem Vakıf University Hospital, with a minimum total of 200 patients.
Who may be able to join
- Adults aged 18-70 years; experiencing chronic symptoms (diarrhea, bloating, abdominal pain, constipation, flatulence) for the past 3 months, potentially fitting IBS criteria.
Who cannot join
- Acute gastroenteritis (< 4 weeks), Active gastrointestinal bleeding (stomach, small intestine, and colon), Known celiac disease, Bariatric surgery or short bowel syndrome, Pregnancy or lactation, Type I and II Diabetes mellitus, Antibiotic use within the last 2 weeks, High-dose NSAIDs within the last 2 weeks, Initiation of probiotics or prebiotics within the last 4 weeks, High-dose PPI use (optional), Inflammatory bowel disease (IBD; ulceretive colitis and Crohn's colitis) with active severe flare (excluded from primary analyses, evaluated separately in subgroup analyses)
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
Turkey (Türkiye)1 site
Bezmialem Vakıf University Medical Faculty Hospital
Istanbul, 34093
About this study
Official title: Observational Cross-Sectional Study of Intestinal Permeability in Adults With Lactose Intolerance
"This study evaluates the interplay between lactose intolerance, intestinal barrier function (zonulin), and intestinal inflammation (fecal calprotectin) in adults, aiming to clarify their independent contributions to symptom severity and quality of life."
Read the detailed description
The gastrointestinal system's barrier functions play a critical role in maintaining intestinal and overall health. Tight junction structures, regulated by zonulin, are key components of this barrier, and elevated zonulin levels can increase intestinal permeability, facilitating translocation of luminal particles into the systemic circulation and promoting inflammation. Fecal zonulin-related proteins (ZRP) provide a non-invasive marker of intestinal barrier integrity.
Calprotectin, a pro-inflammatory protein complex released from neutrophils, serves as a reliable biomarker of mucosal inflammation. While typically normal in functional disorders such as irritable bowel syndrome (IBS), fecal calprotectin (FC) is significantly elevated in inflammatory bowel diseases (IBD), helping to distinguish organic inflammatory conditions from functional disorders.
Lactose intolerance (LI) results from lactase deficiency and is characterized by abdominal pain, bloating, and diarrhea. Traditionally attributed to mechanical and fermentative processes, recent evidence suggests that immunological and inflammatory mechanisms may also contribute. LI can be primary (genetic lactase deficiency) or secondary (due to epithelial damage or barrier dysfunction), with barrier disruption potentially exacerbating symptom severity.
Recent studies have reported elevated fecal calprotectin in individuals with self-reported milk intolerance (Seidita et al., 2023), even among those confirmed as lactose intolerant by hydrogen breath testing, suggesting that additional inflammatory or allergic mechanisms may be involved. Moreover, dietary interventions in IBS patients with food intolerances, including lactose, have been shown to significantly reduce calprotectin levels (Schnedl et al., 2023), indicating that inflammation may be modifiable.
Therefore, evaluating zonulin and calprotectin levels in lactose-intolerant adults can provide insights not only into mechanical or chemical causes of symptoms but also into intestinal barrier dysfunction and underlying inflammation. Current literature on combined assessment of these biomarkers in adults is limited. This study aims to:
Investigate the relationship between lactose intolerance and zonulin/fecal calprotectin levels.
Assess the independent contribution of zonulin (intestinal permeability) separate from calprotectin (inflammation).
Explore associations between these biomarkers, symptom severity, and quality of life.
- Keywords
- Zonulin, Lactose tolerance test, Bristol stool scale, Fecal calprotectin, Gastrointestinal symtom rating scale, IBS-symptom severity scale, IgE specific casein
- Medical subject headings
- Lactose Intolerance, Adult Type, Irritable Bowel Syndrome
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
| Study group | Role | What they receive |
|---|---|---|
| Patients with Irritable bowel sydrome. | IBS-C, IBS-D and IBS-M. |
What is being measured
The primary outcome is the main question the study is designed to answer.
To determine the relationship between lactose intolerance (LI) and fecal biomarkers, zonulin (Z) and fecal calprotectin (FC), in adults with IBS.
The primary outcome of this study is to evaluate the relationship between lactose intolerance (LI) and fecal biomarkers-Z (as mg/kg), a marker of intestinal permeability (IP), and fecal calprotectin (FC) (as mg/kg), a marker of intestinal inflammation-in adults with irritable bowel syndrome (IBS). This includes assessing whether levels of these biomarkers are associated with the presence of LI and the severity of gastrointestinal symptoms related to lactose ingestion. The analysis aims to clarify how intestinal barrier function (Z) and inflammation (FC) contribute individually and jointly to symptom manifestation in LI patients within the IBS population.
Measured: Baseline assessment (single time point measurement of biomarkers and symptoms)
Secondary outcomes (1)
FC predictive value with Z. Z correlation with symptom severity. Z in IBS subtypes / FC and organic pathology. Z mediation between LI and symptoms. IgE anti-casein and symptom severity. LTT correlation with IP biomarkers. Celiac serology prevalence.
Predictive value of FC (mg/kg) and Z (mg/kg) for LI. Correlation of Z with gastrointestinal symptom severity (GSRS) and irritabl bowel disese-symptom severity score (IBS-SSS).
Z levels across IBS subtypes and association of FC with organic pathology. Mediating role of Z between LI and symptoms. Relationship between IgE anti-casein (kIU/Lt) positivity and symptom severity according to IBS-SSS.
Correlation of lactose tolerance test (LTT) results with intestinal permeability biomarkers. Prevalence of positive celiac serology (anti IgA endomycium antibody (titre) and Anti IgA transglutaminase antibody (RU/ml).
Measured: Baseline assessment (single measurement at the time of evaluation)
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted20 Feb 2026
- Study start10 Feb 2026
- Primary completion15 Dec 2026 (estimated)
- Study completion15 Jun 2027 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Publications (8)Papers the sponsor has linked to this study.
- Other trials for Lactose Intolerance, Adult TypeStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Observational
- Observational model
- Other
- Time perspective
- Cross-sectional
- Enrolment
- 200 participants (estimated)
- Target duration
- 12 Weeks
Sponsor and investigators
- Lead sponsor
- Bezmialem Vakif University
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07424898
- Sponsor's protocol ID
- E-54022451-050.04-212534
- Acronym
- LI
- Status last verified
- Feb 2026
- First submitted
- 16 Feb 2026
- Last updated
- 25 Feb 2026
- Results posted
- No
- Data monitoring committee
- No
- FDA-regulated drug
- No
- FDA-regulated device
- No
- Individual data sharing
- No: "Due to privacy and confidentiality concerns, individual participant data will not be shared."
Publications
Guingand DE Rivery M, Zeinab H, Cohen V, Baumstarck K, Luciano L, Vitton V. Does fecal calprotectin increase may be linked to lactose intolerance in patients with irritable bowel syndrome? Minerva Gastroenterol (Torino). 2023 Sep;69(3):329-334. doi: 10.23736/S2724-5985.21.02802-6. Epub 2021 Apr 8.
PubMed 33829725Jendraszak M, Galecka M, Kotwicka M, Schwiertz A, Regdos A, Pazgrat-Patan M, Andrusiewicz M. Impact of Biometric Patient Data, Probiotic Supplementation, and Selected Gut Microorganisms on Calprotectin, Zonulin, and sIgA Concentrations in the Stool of Adults Aged 18-74 Years. Biomolecules. 2022 Nov 29;12(12):1781. doi: 10.3390/biom12121781.
PubMed 36551209Tyszka M, Maciejewska-Markiewicz D, Bilinski J, Lubas A, Stachowska E, Basak GW. Increased Intestinal Permeability and Stool Zonulin, Calprotectin and Beta-Defensin-2 Concentrations in Allogenic Hematopoietic Cell Transplantation Recipients. Int J Mol Sci. 2022 Dec 15;23(24):15962. doi: 10.3390/ijms232415962.
PubMed 36555600Czaja-Bulsa G, Bulsa K, Lokiec M, Drozd A. Can Faecal Zonulin and Calprotectin Levels Be Used in the Diagnosis and Follow-Up in Infants with Milk Protein-Induced Allergic Proctocolitis? Nutrients. 2024 Sep 2;16(17):2949. doi: 10.3390/nu16172949.
PubMed 39275265Szymanska E, Wierzbicka A, Dadalski M, Kierkus J. Fecal Zonulin as a Noninvasive Biomarker of Intestinal Permeability in Pediatric Patients with Inflammatory Bowel Diseases-Correlation with Disease Activity and Fecal Calprotectin. J Clin Med. 2021 Aug 30;10(17):3905. doi: 10.3390/jcm10173905.
PubMed 34501351Schnedl WJ, Michaelis S, Enko D, Mangge H. Fecal Calprotectin Elevations Associated with Food Intolerance/Malabsorption Are Significantly Reduced with Targeted Diets. Nutrients. 2023 Feb 27;15(5):1179. doi: 10.3390/nu15051179.
PubMed 36904178Seidita A, Mansueto P, Giuliano A, Chiavetta M, Soresi M, Carroccio A, The Internal Medicine Study Group. Fecal Calprotectin in Self-Reported Milk Intolerance: Not Only Lactose Intolerance. Nutrients. 2023 Feb 20;15(4):1048. doi: 10.3390/nu15041048.
PubMed 36839406Fasano A. Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011 Jan;91(1):151-75. doi: 10.1152/physrev.00003.2008.
PubMed 21248165
Study at a glance
From the registry record, last updated by the sponsor on 25 Feb 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Observational Cross-Sectional Study of Intestinal Permeability in Adults With Lactose Intolerance
- ClinicalTrials.gov ID
- NCT07424898
- Acronym / sponsor ID
- LI / E-54022451-050.04-212534
- Keywords
- Zonulin, Lactose tolerance test, Bristol stool scale, Fecal calprotectin, Gastrointestinal symtom rating scale, IBS-symptom severity scale, IgE specific casein
- Study type
- Observational
- Recruitment status
- Enrolling by invitation
- Enrolment
- 200 participants (estimated)
- Lead sponsor
- Bezmialem Vakif UniversityUniversity, hospital or other
- Study start
- 10 Feb 2026 (actual)
- Primary completion
- 15 Dec 2026 (estimated)
- Study completion
- 15 Jun 2027 (estimated)
- First posted
- 20 Feb 2026 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
"This study evaluates the interplay between lactose intolerance, intestinal barrier function (zonulin), and intestinal inflammation (fecal calprotectin) in adults, aiming to clarify their independent contributions to symptom severity and quality of life."
Detailed description
The gastrointestinal system's barrier functions play a critical role in maintaining intestinal and overall health. Tight junction structures, regulated by zonulin, are key components of this barrier, and elevated zonulin levels can increase intestinal permeability, facilitating translocation of luminal particles into the systemic circulation and promoting inflammation. Fecal zonulin-related proteins (ZRP) provide a non-invasive marker of intestinal barrier integrity.
Calprotectin, a pro-inflammatory protein complex released from neutrophils, serves as a reliable biomarker of mucosal inflammation. While typically normal in functional disorders such as irritable bowel syndrome (IBS), fecal calprotectin (FC) is significantly elevated in inflammatory bowel diseases (IBD), helping to distinguish organic inflammatory conditions from functional disorders.
Lactose intolerance (LI) results from lactase deficiency and is characterized by abdominal pain, bloating, and diarrhea. Traditionally attributed to mechanical and fermentative processes, recent evidence suggests that immunological and inflammatory mechanisms may also contribute. LI can be primary (genetic lactase deficiency) or secondary (due to epithelial damage or barrier dysfunction), with barrier disruption potentially exacerbating symptom severity.
Recent studies have reported elevated fecal calprotectin in individuals with self-reported milk intolerance (Seidita et al., 2023), even among those confirmed as lactose intolerant by hydrogen breath testing, suggesting that additional inflammatory or allergic mechanisms may be involved. Moreover, dietary interventions in IBS patients with food intolerances, including lactose, have been shown to significantly reduce calprotectin levels (Schnedl et al., 2023), indicating that inflammation may be modifiable.
Therefore, evaluating zonulin and calprotectin levels in lactose-intolerant adults can provide insights not only into mechanical or chemical causes of symptoms but also into intestinal barrier dysfunction and underlying inflammation. Current literature on combined assessment of these biomarkers in adults is limited. This study aims to:
Investigate the relationship between lactose intolerance and zonulin/fecal calprotectin levels.
Assess the independent contribution of zonulin (intestinal permeability) separate from calprotectin (inflammation).
Explore associations between these biomarkers, symptom severity, and quality of life.
Study design
- Observational model
- Other
- Time perspective
- Cross-sectional
- Target follow-up
- 12 Weeks
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| Patients with Irritable bowel sydrome. | – | –IBS-C, IBS-D and IBS-M. |
Who may qualify
- Ages
- 18 to 70 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
- Study population
- Patients with IBS, aged 18-70 years, both male and female, who meet the Rome-4 criteria, were included in this study. They were recruited from the Gastroenterology outpatient clinic of Bezmialem Vakıf University Hospital, with a minimum total of 200 patients.
Key inclusion criteria (1 listed)
- Adults aged 18-70 years; experiencing chronic symptoms (diarrhea, bloating, abdominal pain, constipation, flatulence) for the past 3 months, potentially fitting IBS criteria.
Key exclusion criteria (1 listed)
- Acute gastroenteritis (< 4 weeks), Active gastrointestinal bleeding (stomach, small intestine, and colon), Known celiac disease, Bariatric surgery or short bowel syndrome, Pregnancy or lactation, Type I and II Diabetes mellitus, Antibiotic use within the last 2 weeks, High-dose NSAIDs within the last 2 weeks, Initiation of probiotics or prebiotics within the last 4 weeks, High-dose PPI use (optional), Inflammatory bowel disease (IBD; ulceretive colitis and Crohn's colitis) with active severe flare (excluded from primary analyses, evaluated separately in subgroup analyses)
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Primary outcome
To determine the relationship between lactose intolerance (LI) and fecal biomarkers, zonulin (Z) and fecal calprotectin (FC), in adults with IBS.
Time frame: Baseline assessment (single time point measurement of biomarkers and symptoms)
The primary outcome of this study is to evaluate the relationship between lactose intolerance (LI) and fecal biomarkers-Z (as mg/kg), a marker of intestinal permeability (IP), and fecal calprotectin (FC) (as mg/kg), a marker of intestinal inflammation-in adults with irritable bowel syndrome (IBS). This includes assessing whether levels of these biomarkers are associated with the presence of LI and the severity of gastrointestinal symptoms related to lactose ingestion. The analysis aims to clarify how intestinal barrier function (Z) and inflammation (FC) contribute individually and jointly to symptom manifestation in LI patients within the IBS population.
1 secondary outcome
FC predictive value with Z. Z correlation with symptom severity. Z in IBS subtypes / FC and organic pathology. Z mediation between LI and symptoms. IgE anti-casein and symptom severity. LTT correlation with IP biomarkers. Celiac serology prevalence.
Time frame: Baseline assessment (single measurement at the time of evaluation)
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 25 Feb 2026.
- Results publication: PubMed 33829725Guingand DE Rivery M, Zeinab H, Cohen V, Baumstarck K, Luciano L, Vitton V. Does fecal calprotectin increase may be linked to lactose intolerance in patients with irritable bowel syndrome? Minerva Gastroenterol (Torino). 2023 Sep;69(3):329-334. doi: 10.23736/S2724-5985.21.02802-6. Epub 2021 Apr 8.
- Results publication: PubMed 36551209Jendraszak M, Galecka M, Kotwicka M, Schwiertz A, Regdos A, Pazgrat-Patan M, Andrusiewicz M. Impact of Biometric Patient Data, Probiotic Supplementation, and Selected Gut Microorganisms on Calprotectin, Zonulin, and sIgA Concentrations in the Stool of Adults Aged 18-74 Years. Biomolecules. 2022 Nov 29;12(12):1781. doi: 10.3390/biom12121781.
- Results publication: PubMed 36555600Tyszka M, Maciejewska-Markiewicz D, Bilinski J, Lubas A, Stachowska E, Basak GW. Increased Intestinal Permeability and Stool Zonulin, Calprotectin and Beta-Defensin-2 Concentrations in Allogenic Hematopoietic Cell Transplantation Recipients. Int J Mol Sci. 2022 Dec 15;23(24):15962. doi: 10.3390/ijms232415962.
- Results publication: PubMed 39275265Czaja-Bulsa G, Bulsa K, Lokiec M, Drozd A. Can Faecal Zonulin and Calprotectin Levels Be Used in the Diagnosis and Follow-Up in Infants with Milk Protein-Induced Allergic Proctocolitis? Nutrients. 2024 Sep 2;16(17):2949. doi: 10.3390/nu16172949.
- Results publication: PubMed 34501351Szymanska E, Wierzbicka A, Dadalski M, Kierkus J. Fecal Zonulin as a Noninvasive Biomarker of Intestinal Permeability in Pediatric Patients with Inflammatory Bowel Diseases-Correlation with Disease Activity and Fecal Calprotectin. J Clin Med. 2021 Aug 30;10(17):3905. doi: 10.3390/jcm10173905.
- Results publication: PubMed 36904178Schnedl WJ, Michaelis S, Enko D, Mangge H. Fecal Calprotectin Elevations Associated with Food Intolerance/Malabsorption Are Significantly Reduced with Targeted Diets. Nutrients. 2023 Feb 27;15(5):1179. doi: 10.3390/nu15051179.
- Results publication: PubMed 36839406Seidita A, Mansueto P, Giuliano A, Chiavetta M, Soresi M, Carroccio A, The Internal Medicine Study Group. Fecal Calprotectin in Self-Reported Milk Intolerance: Not Only Lactose Intolerance. Nutrients. 2023 Feb 20;15(4):1048. doi: 10.3390/nu15041048.
- Results publication: PubMed 21248165Fasano A. Zonulin and its regulation of intestinal barrier function: the biological door to inflammation, autoimmunity, and cancer. Physiol Rev. 2011 Jan;91(1):151-75. doi: 10.1152/physrev.00003.2008.
- Individual participant dataSharing planned: No. "Due to privacy and confidentiality concerns, individual participant data will not be shared."
Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
An observational study of Lactose Intolerance, Adult Type and Intestinal Permability, run by Bezmialem Vakif University at 1 site in Turkey (Türkiye).
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 1 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 25 Feb 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in Turkey (Türkiye). Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
To determine the relationship between lactose intolerance (LI) and fecal biomarkers, zonulin (Z) and fecal calprotectin (FC), in adults with IBS. (time frame: Baseline assessment (single time point measurement of biomarkers and symptoms)). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
On the ClinicalTrials.gov record for NCT07424898, which also lists 8 linked publications.
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 25 Feb 2026.