Anxiety, Depression, Healthy, Stress-related Problem
Conditions
Keywords
Probiotics, Academic examination, Psychological stress, Depression, Anxiety
Brief summary
Probiotics are live microorganisms which when administered in adequate amounts confer a health benefit on the host. Accumulating evidence indicates their effect in mental health restoration. Beneficial neuropsychological and psychobiological effects are particularly well substantiated in clinical samples. However, it is not clearly documented whether probiotic supplementation reduces depressive and anxiety symptoms in healthy volunteers experiencing temporal deterioration in mental functioning while facing a stressful event. The combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 is particularly well studied in terms of its central nervous system action with significantly deciphered mechanism. As a result, this combination is particularly promising to study the effect of mental health improvement in healthy volunteers facing a stressful event. The aim of this project is to assess the impact of a 8-week supplementation with probiotic combination of Lactobacillus helveticus R0052 and Bifidobacterium longum R0175 strains in the daily dose of 3 × 10\^9 colony forming units on mental health measures and oral microbiota composition and metabolome in healthy young adults facing a psychologically stressful event. The aim will be achieved by comparing the probiotic combination supplement to placebo in a randomized triple-blind controlled trial settings with a participant allocation ratio of 1:1. The summer academic examination session and the upcoming first take of the final exam in pharmacology at third year of medical studies will be a model of a stressful event. The participants will supplement their diets with probiotic/placebo for 8 weeks before the exam. After giving written informed consent, before the supplementation (relatively stress-free time period in terms of academic activities) the participants will provide background sociodemographic, anthropometric and psychometric data. At that time, participants will also give samples of saliva to assess cortisol and selected cytokines concentrations as well as salivary microbiome and metabolome. At the end of supplementation, a day before the final exam, participants will donate salivary samples and do psychometric tests for the second time to assess the same parameters as at the beginning of the study. Participants will also do a pre-exam test in pharmacology (not considered a formal academic assessment) as a comparator for the results of the formal examination held a day after.
Interventions
DIETARY_SUPPLEMENTLactobacillus helveticus R0052 and Bifidobacterium longum R0175
8-week supplementation (56 days); 3 × 10\^9 CFU/day
DIETARY_SUPPLEMENTPlacebo
8-week supplementation (56 days)
Sponsors
Pomeranian Medical University Szczecin
SANPROBI Sp. z o.o. Sp.k.
Medical University of Lodz
Study design
Allocation
RANDOMIZED
Intervention model
PARALLEL
Primary purpose
PREVENTION
Masking
TRIPLE (Subject, Investigator, Outcomes Assessor)
Intervention model description
Healthy medical students are assigned
Eligibility
Sex/Gender
ALL
Age
18 Years to 30 Years
Healthy volunteers
Yes
Inclusion criteria
* status of a third-year medical student at the Faculty of Medicine of the Medical University of Lodz * age (18-30 years) * high motivation and no formal obstacles to sit the first take of the final exam in pharmacology * Body mass index of 18-25 kg/m2
Exclusion criteria
* chronic dental diseases (in particular periodontal diseases), neurological, psychiatric, cardiological, gastroenterological, endocrinological, immunological, inflammatory or infectious diseases or disorders * psychiatric or neurological diagnosis - within the last 1 year * immune disorders or possible immunodeficiency - within the last 5 years * previous bariatric surgery - within the last 5 years * hospitalization - within the last 3 months * presence of central venous catheters * use of enteral nutrition (feeding tube or nutritional fistula) * pregnant or planning to become pregnant in the next 3 months * breast-feeding * occurrence of an allergic reaction - within the last 3 months * hypersensitivity to potato starch or magnesium stearate * chronic use of any medicinal products - within the last 3 months * use of systemic antibacterial or antifungal drugs - within the last 1 month * alcohol abuse (≥ 20 g or ≥ 40 g of alcohol per day for women and men, respectively) - within the last 3 months * abuse of narcotic or psychotropic substances - within the last 3 months * regular smoking of tobacco or other nicotine products, including e-cigarettes (\> 5 cigarettes or equivalents per day - within the last 3 months) * use of probiotic or prebiotic preparations - within the last 1 month * a vegan diet or any unusual diet
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| Cortisol | Day 0, Day 55 | Salivary cortisol level measured with ELISA test |
| Depression symptoms under examination-related stress | Day 0, Day 55 | Depression symptoms measured with Depression Anxiety Stress Scale - 21 (DASS-21). Seven items, each scored 0 to 3 points, yielding a total between 0 and 21 points. The more points the more severe depression. |
| Anxiety symptoms under examination-related stress | Day 0, Day 55 | Anxiety symptoms measured with Depression Anxiety Stress Scale - 21 (DASS-21). Seven items, each scored 0 to 3 points, yielding a total between 0 and 21 points. The more points the more severe anxiety. |
| Stress symptoms under examination-related stress | Day 0, Day 55 | Stress symptoms measured with Depression Anxiety Stress Scale - 21 (DASS-21). Seven items, each scored 0 to 3 points, yielding a total between 0 and 21 points. The more points the more severe stress. |
| Performance under examination-related stress | Day 56 | Number of correctly-answered questions in the final examination in pharmacology in relation to subject knowledge assessed in the pre-exam test. 60 questions, each scored 0 or 1 point, yielding a total between 0 and 60 points. The more points the better performance under examination-related stress. |
Secondary
| Measure | Time frame | Description |
|---|---|---|
| Depression symptoms under examination-related stress (supportive measure) | Day 0, Day 55 | Depression symptoms measured with Patient Health Questionnaire - 9 (PHQ-9). Nine items, each scored 0 to 3 points, yielding a total between 0 and 27 points. The more points the more severe depression. |
| Anxiety symptoms under examination-related stress (supportive measure) | Day 0, Day 55 | Anxiety symptoms measured with General Anxiety Disorder - 7 (GAD-7). Seven items, each scored 0 to 3 points, yielding a total between 0 and 21 points. The more points the more severe anxiety. |
| Interleukin-1β (IL-1β) | Day 0, Day 55 | Salivary IL-1β level measured with ELISA test in relation to total protein concentration in saliva |
| Fatigue under examination-related stress | Day 0, Day 55 | Fatigue status measured with Fatigue Severity Scale (FSS). Nine items, each scored 1 to 7 points, yielding a total between 7 and 63 points. The more points the greater fatigue severity. |
| Sleep quality under examination-related stress | Day 0, Day 55 | Sleep quality status measured with Pittsburgh Sleep Quality Index (PSQI). Seven components, each scored 0 to 3 points, yielding a total composite score of 0 to 21 points. The more points the more sleep difficulties. |
| Interleukin-8 (IL-8) | Day 0, Day 55 | Salivary IL-8 level measured with ELISA test in relation to total protein concentration in saliva |
| Microbiome | Day 0, Day 55 | Salivary microbiome assessed with 16S rRNA gene sequencing |
| Metabolome | Day 0, Day 55 | Salivary metabolome assessed with liquid chromatography-mass spectrometry |
| Mood | Day 0, Day 55 | Current mood measured with a pictogram-enhanced visual analog mood scale. A single item scored 0 to 10 points, yielding a total between 0 and 10 points. The more points the better mood. |
Countries
Poland
Outcome results
None listed