Anxiety, Gastro-intestinal Symptoms in Healthy Subjects, Sleep, Stress
Conditions
Keywords
Probiotics, Stress, Anxiety, Gut-brain axis
Brief summary
This randomized, double-blind, placebo-controlled study evaluates the efficacy and safety of an 8-week probiotic supplementation (Lactobacillus plantarum LP140 and Bifidobacterium breve BB010 in total daily dose 1 × 10¹⁰ CFU or matching placebo) in reducing perceived stress and anxiety, and improvement related psychological parameters in healthy university students during the examination period. The primary outcome is the change in Perceived Stress Scale (PSS-10) score at week 5 and week 8 of interevention compared to placebo. The secondary outcomes are the changes in DASS-21 subscales (Stress, Anxiety, Depression), State-Trait Anxiety Inventory - State version scale (STAI-S), Sense of Coherence Scale (SOC-29), Pittsburgh Sleep Quality Index (PSQI), self-reported gastrointestinal symptoms (Likert scale) and incidence of adverse events during the 8-week lasting interventional study.
Detailed description
The gut-brain axis enables bidirectional communication between the gastrointestinal tract and the central nervous system. Emerging evidence suggests that selected probiotic strains (psychobiotics) may modulate stress responses and emotional regulation. University examination periods constitute a predictable model of transient psychological stress in otherwise healthy individuals. This study investigates whether daily supplementation with a probiotic combination of Lactobacillus plantarum LP140 and Bifidobacterium breve BB010 reduces perceived stress and improves related psychological parameters in healthy students exposed to exam-related stress. Two hundred male and female students aged 18-40 years with at least moderate stress and mild anxiety, but without clinical depression, will be enrolled at the Medical University of Lublin, Poland. After providing written informed consent and confirming eligibility criteria, participants will be randomized in a 1:1 ratio to receive either a probiotic formulation containing Lactobacillus plantarum LP140 and Bifidobacterium breve BB010 (total daily dose of 1 × 10¹⁰ colony-forming units) or a matching placebo. The investigational product and placebo will be identical in appearance and administered orally once daily (two capsules) for 8 weeks. Randomization will be computer-generated, and both participants and investigators will remain blinded to treatment allocation throughout the study. The intervention will begin approximately six weeks before the first scheduled academic examination. Study assessments will be conducted at baseline, at week 5 (approximately one week before the first examination), and at week 8 (±3 days before a subsequent examination). Psychological and functional parameters will be collected using validated self-report instruments administered electronically, with selected assessments performed during on-site visits. Participants will be asked to maintain their usual diet, physical activity, and caffeine intake during the study period. Safety and tolerability will be monitored throughout the intervention, and adverse events will be recorded using an electronic reporting system with daily reminders. The study is powered to detect clinically meaningful differences between groups in perceived stress levels and will be analyzed using appropriate covariance-based statistical models adjusted for baseline values and relevant covariates. All participant data will be coded to ensure confidentiality and handled in accordance with applicable data protection regulations.
Interventions
DIETARY_SUPPLEMENTProbiotics
Lactobacillus plantarum LP140 and Bifidobacterium breve BB010
OTHERPlacebo
Maltodextrin
Sponsors
Nordic Biotic Sp. z o.o.
Wörwag Pharma GmbH & Co. KG
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
QUADRUPLE (Subject, Caregiver, Investigator, Outcomes Assessor)
Eligibility
Sex/Gender
ALL
Age
18 Years to 40 Years
Healthy volunteers
No
Inclusion criteria
* Male or female students aged 18-40 years * At least moderate stress (DASS-21 Stress score ≥10) * Mild anxiety (DASS-21 Anxiety score 6-13) * No clinical depression (DASS-21 Depression score ≤9) * Willingness to maintain usual diet, physical activity, and intake of caffeinated beverages during the study * Written informed consent
Exclusion criteria
* Irritable bowel syndrome (Rome IV criteria) or any chronic intestinal disease (including celiac disease) * Known food allergies, immunodeficiency disorders, or immunosuppressive treatment * Antibiotic use within 4 weeks prior to screening * Any psychiatric illness within the past 5 years * Any malignant disease or autoimmune or allergic diseases (e.g., atopic dermatitis, asthma) * Use of systemic psychotropic medications or steroids; use of topical corticosteroid creams within 4 weeks prior to screening * Pregnancy, breastfeeding, or plans to become pregnant during the study * Probiotic or prebiotic consumption or planned dietary changes within 4 weeks prior to screening * Heavy caffeine consumption (\>4 cups of 300 mL coffee per day) * Drug or alcohol addiction or regular use of recreational drugs * Smoking more than 10 cigarettes per day
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Change in perceived stress score | Change in total perceived stress score from baseline to week 5 and to week 8 (±3 days) compared to placebo | Perceived stress will be assessed using the 10-Item Perceived Stress Scale (PSS-10), a validated questionnaire measuring the degree to which situations in one's life are appraised as stressful. The total score ranges from 0 to 40, with higher scores indicating higher perceived stress levels (worse outcome). Changes in the total score from baseline will be analyzed to evaluate the effect of probiotic supplementation. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Change in stress, anxiety and depression scores | Change in DASS-21 Stress, Anxiety, and Depression subscale scores from baseline to week 5 and week 8 (±3 days) compared to placebo. | Stress, anxiety, and depression will be assessed using the Depression Anxiety Stress Scales - 21 Items (DASS-21). The DASS-21 consists of three subscales (Depression, Anxiety, and Stress), each including 7 items. Scores for each subscale range from 0 to 42 after standard score multiplication, with higher scores indicating greater symptom severity (worse outcome). Changes in the Stress, Anxiety, and Depression subscale scores from baseline will be analyzed to evaluate the effect of probiotic supplementation. |
| Change in sleep quality score | Change in Pittsburgh Sleep Quality Index (PSQI) global score from baseline to week 5 and week 8 (±3 days) compared to placebo. | Sleep quality will be assessed using the Pittsburgh Sleep Quality Index (PSQI), a validated questionnaire measuring sleep quality over the previous month. The global PSQI score ranges from 0 to 21, with higher scores indicating poorer sleep quality (worse outcome). Changes in the PSQI global score from baseline will be analyzed to evaluate the effect of probiotic supplementation. |
| Change in sense of coherence score | Change in Sense of Coherence Scale - 29 Items (SOC-29) total score from baseline to week 5 and week 8 (±3 days) compared to placebo. | Sense of coherence will be assessed using the Sense of Coherence Scale - 29 Items (SOC-29), a validated questionnaire measuring psychological resilience and the ability to cope with stress. The total score ranges from 29 to 203, with higher scores indicating a stronger sense of coherence (better outcome). Changes in the SOC-29 total score from baseline will be analyzed to evaluate the effect of probiotic supplementation. |
| Change in state anxiety score | Change in State-Trait Anxiety Inventory - State version (STAI-S) total score from baseline to week 8 compared to placebo. | State anxiety will be assessed using the State-Trait Anxiety Inventory - State version (STAI-S), a validated questionnaire measuring the current level of anxiety. The STAI-S total score ranges from 20 to 80, with higher scores indicating higher levels of anxiety (worse outcome). Changes in the STAI-S total score from baseline will be analyzed to evaluate the effect of probiotic supplementation. |
| Change in severity of gastro-intestinal symptoms | Change from baseline in gastro-intestinal severity score at Week 5 and Week 8 compared to placebo | The severitty of gastro-intestinal symptoms will be assessed with the use of 4-point Likert scale (0 - no symptom, 1 - weak, 2 - moderate, 4 - severe). The following symptoms will be assessed: abdominal pain, flatulence, nausea. |
| Incidence of treatment-emergent adverse events (Safety and Tolerability) | From baseline through the 8-week intervention period. | Safety and tolerability will be assessed by monitoring the incidence of adverse events throughout the study. Adverse events will be self-reported by participants using an electronic reporting platform, which provides daily reminders for study product intake and allows participants to record any symptoms or adverse events experienced during the study period. |
Countries
Poland
Contacts
CONTACTEmilia Majsiak, Professor of University, PhD
CONTACTBożena Cukrowska, Prof., MD, PhD
PRINCIPAL_INVESTIGATOREmilia Majsiak, Prof. PhD
Medical University of Lublin
Outcome results
None listed