Effect of Probiotic on Cognitive Function

Effect of Probiotic Supplementation on Cognitive Function and Gut-Brain Axis Modulation in Females With Mild Depression

Overview

Key facts that identify this study and show where it stands today.

ClinicalTrials.gov ID: NCT07776145
Lead Sponsor: Cairo UniversityOTHER
Overall Status: Not yet recruiting
Study Type: Interventional
Phase: Not Applicable
Enrollment: 88Estimated
Last Update Posted: Aug 20, 2026Actual
Start Date: Sep 2026Estimated
Primary Completion Date: Sep 2027Estimated
Completion Date: Oct 2027Estimated

Description

What the study is about and why it is being run, in the researchers' own words.

Official Title: Effect of Probiotic Supplementation on Cognitive Function and Gut-Brain Axis Modulation in Females With Mild Depression
Brief Summary: The goal of this clinical trial is to learn if daily single-strain probiotic supplementation (Lactobacillus plantarum) works to improve cognitive function and depressive symptoms in Egyptian women aged 50-64 years with mild depression. It will also learn about its effects on systemic inflammation and autonomic nervous system function via the gut-brain axis

The main questions it aims to answer are:

Does a 12-week probiotic supplementation improve cognitive function (measured by MoCA-B) compared to a placebo? Does it reduce the severity of depressive symptoms (measured by BDI-II)? Does it reduce systemic inflammation (measured by hs-CRP levels in the blood)? Does it enhance autonomic nervous system function (measured by Heart Rate Variability - HRV via a smartphone app)? Researchers will compare the probiotic capsule (Lactobacillus plantarum, 10 billion CFU) to a placebo (a look-alike capsule containing starch) to see if the probiotic works better than placebo.

Participants will:

Take one probiotic or placebo capsule orally every morning with breakfast for 12 weeks.

Visit the Family Medicine outpatient clinic at baseline and at 12 weeks for cognitive and psychological tests, HRV measurements, and blood tests.

Receive weekly follow-up messages on WhatsApp to monitor adherence and report any dietary changes or potential side effects.

Conditions

The medical conditions and diseases this study investigates.

Cognition Function
Mild Depression

Interventions

The treatments and procedures being evaluated in this study.

Lactobacillus plantarum
placebo capsule

Participation

Who can join this study and the criteria used to decide.

Ages Eligible for Study: Adult (18-64)
Sexes Eligible for Study: Female
Accepts Healthy Volunteers: No
Eligibility Criteria: Inclusion Criteria:

Females, aged 50-64 years

Presence of mild depressive symptoms, defined as a Beck Depression inventory II (BDI-II) total score between 14 and 19 (inclusive) at the screening visit.

Ability to give informed consent

Exclusion Criteria:

Moderate and severe depression (BDI-II score > 19) or active suicidal ideation (assessed by clinical interview).

Diagnosis of bipolar disorder, schizophrenia, or other major psychotic disorder.

Current use of antidepressants, antipsychotics, mood stabilizers, or regular anxiolytics

Regular consumption of probiotics, prebiotics, or synbiotic supplements within the past 4 weeks.

Use of antibiotics or antifungals within the past 4weeks.

Known diagnosis of inflammatory bowel disease, celiac disease, or active irritable bowel syndrome with severe symptoms.

History of significant cardiovascular disease (e.g., atrial fibrillation, heart failure, recent MI), uncontrolled hypertension, or type 1 diabetes.

Current use of systemic hormone replacement therapy within the last 3 months.Research Template 6 Final Version: Jan 2024

Known allergy to any component of the probiotic or placebo.

Severe systemic illness (e.g., uncontrolled diabetes, malignancy, severe hepatic, renal disease or auto-immune diseases).

CRP more than 10

Design

How the study is designed and how its participant groups are organized.

Primary Purpose: Treatment
Allocation: Randomized
Interventional Model: Parallel Assignment
Masking: Triple

Contacts

The people to reach with questions about this study or how to join it.

Marina S Girgis, MDContact

marina.riad38728@postgrad.kasralainy.edu.eg02-1287128004

Locations

Where the study is run and whether each site is currently recruiting.

Cairo University (Kasr Alainy teaching hospitals)

Cairo, Egypt

Collaborators

The organizations and people involved in this study.

Lead Sponsor: Cairo UniversityOTHER

Similar Studies

Other registered studies that closely resemble this one.

Detailed Description

Depression poses a significant global public health challenge, with women being two to three times more likely than men to develop the condition. Emerging evidence highlights a bidirectional relationship between depression, cognitive impairment, and the gut microbiota via the gut-brain axis. Dysbiosis in gut microbiota can contribute to systemic inflammation, impaired neurogenesis, and psychiatric disorders. Specific strains such as Lactobacillus plantarum have shown potential in modulating gut-brain communication, reducing inflammation, and improving neurocognitive and psychological outcomes.

This triple-blind, randomized, placebo-controlled trial aims to evaluate the efficacy of a 12-week intervention with a single-strain probiotic (Lactobacillus plantarum, 10 billion CFU daily) compared to a placebo in Egyptian women aged 50-64 years presenting with mild depressive symptoms.

Study Procedures and Flow:

Initial Screening Visit: Potential participants recruited from the Family Medicine outpatient clinics at Kasr Al-Ainy Teaching Hospitals will undergo screening. Eligibility will be confirmed by taking a comprehensive medical/psychiatric history, reviewing concomitant medications/supplements, and evaluating depressive symptoms using the Arabic validated Beck Depression Inventory-II (BDI-II, score 14-19). Eligible participants will provide written informed consent.

Baseline Assessment (Week 0): Enrolled participants will undergo baseline evaluations including:

Socio-demographic status assessment. Anthropometric measurements (weight, height, BMI). Cognitive assessment using the Arabic version of the Montreal Cognitive Assessment - Basic (MoCA-B).

Autonomic nervous system function evaluation via short-term (5-minute) resting Heart Rate Variability (HRV) measured using a smartphone-based photoplethysmography application (Welltory) under standardized conditions.

Fasting venous blood sample collection for high-sensitivity C-reactive protein (hs-CRP) level measurement.

Randomization and Intervention Phase (Weeks 1-12): Participants will be randomly allocated in a 1:1 ratio to either the probiotic or placebo group using a computer-generated permuted block design. Both intervention (probiotic) and control (placebo) capsules are identical in appearance, size, color, and packaging. Participants, assessors, and the data analyst/statistician will remain blinded throughout the study. Participants will take one capsule daily with breakfast for 12 weeks. Adherence will be monitored through weekly messaging and monthly capsule counts during study visits.

Post-Intervention Assessment (Week 12): At the end of the 12-week intervention period, participants will undergo repeat outcome assessments identical to baseline (MoCA-B, BDI-II, HRV, and fasting serum hs-CRP).