Oral Bifidobacterium Longum for Skin Barrier Dysfunction in Obesity

Shenzhen People's Hospital140 enrolled

Overview

This clinical trial aims to evaluate the safety and efficacy of oral Bifidobacterium longum supplementation for treating obesity-induced skin barrier impairment in individuals aged 18-40 with BMI ≥30, compared to healthy controls. The study focuses on the following questions: Can oral Bifidobacterium supplementation reduce skin barrier damage (measured by transepidermal water loss/TEWL) in obese participants? Does modulation of gut microbiota with Bifidobacterium longum impact skin barrier function and systemic inflammation? Researchers will compare outcomes across two groups: * Intervention Group (Obese): Oral Bifidobacterium longum capsules * Placebo Control Group (Obese): Oral inactive Bifidobacterium longum (heat-killed) Participant Procedures: Take daily oral capsules (Bifidobacterium longum or inactive strain) for 4 weeks Undergo non-invasive skin testing (TEWL measurements) at baseline and study completion Provide blood, stool, and skin swab samples for inflammation and microbiome analyses Complete weekly check-ins to report adverse effects (e.g., gastrointestinal discomfort, skin irritation)

Study Type

INTERVENTIONAL

Allocation

RANDOMIZED

Purpose

TREATMENT

Masking

SINGLE

Enrollment

140

Conditions

Skin Barrier to Water Loss Microbial Colonization

Eligibility

Sex: ALLMin age: 18 YearsMax age: 40 YearsHealthy volunteers:

Medical Language ↔ Plain English

Inclusion Criteria : * 1\. Meets 2020 WHO BMI classification: * a. Normal weight (18.5-24.9 kg/m²) * b. Overweight (25-29.9 kg/m²) * c. Obesity (≥30 kg/m²) * 2\. Presence of skin barrier impairment (e.g., dryness, erythema, desquamation, or itching) * 3\. Age 18-40 years * 4\. Generally good health (no active systemic diseases) * 5\. Able and willing to provide written informed consent * 6\. No use of oral/topical medications or probiotics within 6 months prior * 7\. No active skin disease or traumatic skin lesions Exclusion Criteria : * 1\. Known allergy or hypersensitivity to probiotics, placebo, or investigational product * 2\. Active skin disease (e.g., psoriasis, eczema, infection) requiring treatment * 3\. Severe medical conditions: * a. Cardiopulmonary disease (NYHA class III/IV) * b. Uncontrolled diabetes (HbA1c \>9%) * c. Autoimmune disorders * 4\. Pregnant or breastfeeding women * 5\. Any condition that may interfere with protocol compliance (per investigator judgement), including: * a. Inability to understand study procedures * b. History of poor clinical trial adherence * 6\. Concurrent participation in other interventional trials

Outcomes

Primary Outcomes

Mean change in transepidermal water loss (TEWL, g/h/m²) on the volar forearm from baseline to 1 month after intervention, measured by Tewameter

TEWL will be assessed on the volar aspect of the forearm using a Tewameter device under standardized environmental conditions (controlled temperature and humidity). At each time point, TEWL will be measured at three predefined skin sites on the volar forearm, and the average value will be used. The primary outcome will be the mean change in TEWL (g/h/m²) from baseline (Day 0) to 1 month after intervention. Lower TEWL values indicate improved skin barrier function.