Probiotics and Examination-related Stress in Healthy Medical Students

Inclusion Criteria: * Being a third year medical student of the Faculty of Medicine or Faculty of Military Medicine, Medical University of Lodz Exclusion Criteria: * formal inability to sit the first attempt of the final examination of Basic Medical Pharmacology * chronic diseases: neurological, psychiatric, cardiological, gastroenterological, immunological, endocrine or infectious * state of immunosuppression * history of hospitalization (\< 3 months before entrance to the study) * presence of central venous catheter * parenteral nutrition * current pregnancy or intention to become pregnant within 3 months from the entrance to the study * current lactation * allergic reaction (\< 3 months before entrance to the study) * hypersensitivity to yeast, maltodextrins, potato starch, magnesium stearate, hypromellose, gelatin, glycerol or titanium dioxide * body mass index over 30 * chronic medication use (current or \< 3 months before entrance to the study) * systemic antibacterial or antifungal medication use (current or \< 3 months before entrance to the study) * overuse of alcohol or psychoactive substances (current or \< 3 months before entrance to the study) * tobacco smoking - more than 5 cigarettes (or equivalents) a day (currently or \< 3 months before entrance to the study) * pro- or prebiotic preparations intake (\< 3 months before entrance to the study) * vegan or other atypical diet * doing professional or extreme sports