Lactose Intolerance and Intestinal Permability

N/AEnrolling By InvitationNCT07424898

Bezmialem Vakif University200 enrolled

Overview

"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."

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 Type

OBSERVATIONAL

Enrollment

200

Conditions

Lactose Intolerance, Adult Type Intestinal Permability IBS (Irritable Bowel Syndrome)

Eligibility

Sex: ALLMin age: 18 YearsMax age: 70 Years

Medical Language ↔ Plain English

Inclusion Criteria: * Adults aged 18-70 years; experiencing chronic symptoms (diarrhea, bloating, abdominal pain, constipation, flatulence) for the past 3 months, potentially fitting IBS criteria. Exclusion Criteria: \- 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)

Locations (1)

Bezmialem Vakıf University Medical Faculty Hospital

Istanbul, Turkey (Türkiye)

Outcomes

Primary Outcomes

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.

Time frame: Baseline assessment (single time point measurement of biomarkers and symptoms)

Secondary Outcomes

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).

Time frame: Baseline assessment (single measurement at the time of evaluation)

Data from ClinicalTrials.gov

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