The purpose of this study is to investigate the effects of a probiotic blend on qualitative (subjective interviews and self-reporting) and quantitative (changes in brain activity, heart rate, cortisol, and reactivity) measures of stress in healthy undergraduate students.
There is a burgeoning literature involving nonhuman animal and human studies linking the microbiota environment in the gut to brain-behaviour relations. For example, animal studies demonstrate that germ-free rodents show heightened HPA-axis responses to stress compared to gnotobiotic animals. There are also a number of nonhuman and human studies that show positive effects of reducing stress after being treated with different probiotics. For example, in one recent double blind study in humans using standardized questionnaires indicated a greater reduction of stress and anxiety symptoms after one month of supplementation with a probiotic formulation compared to placebo. The groups were also differentiated by urinary cortisol levels after treatment. Other studies have found positive effects of probiotic treatment and stress reduction using other probiotics. Accordingly, there is accumulating empirical evidence from animal and human studies of the positive effects of probiotic treatment on stress reduction. In this study, the investigators will investigate the stress reduction effects of the Lallemand Health Solutions (LHS) Probio'Stick® on healthy undergraduate students. The study will be conducted at the McMaster LIVELab, which is capable of collecting both physiological and behavioural measures from groups of up to 100 participants at a time. Registration into this clinical trial will require students be screened via McMaster's SONA system (mcmaster.sona-systems.com). After the screening, participants that are eligible to participate will be given the option to register for an information meeting at which point one may opt to enrol in the study or not. Once in the study, participants will undergo an initial screening in the LIVELab where they will be exposed to auditory, visual, and performance based stressors to measure a baseline. After such point, they will be randomized to receive Probio'Stick® or placebo for a 6-week, once daily, probiotic treatment at home. Following the 6 week intervention, participants will return to the lab for a second testing using the same procedures to establish a change from baseline.
Study Type
INTERVENTIONAL
Allocation
RANDOMIZED
Purpose
TREATMENT
Masking
QUADRUPLE
Enrollment
128
One sachet daily, without or without meals (3 x 10\^9 CFU per sachet) (Lactobacillus helveticus R0052 and Bifidobacterium longum subsp. longum R0175)
One sachet daily, without or without meals (0 CFU per sachet)
McMaster LIVELab
Hamilton, Ontario, Canada
Changes in right frontal electroencephalography (EEG)/brain activity
Is a measure of stress/arousal
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in salivary cortisol concentrations
Collected via Salivette®, before and after each session in the lab.
Time frame: Pre and Post Visit 1 and Visit 2 (6 weeks apart)
Change in the magnitude of startle response
Measured as facial electromyography (EMG) change
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in sympathetic nervous system activation
Calculated as a measure of Heart Rate Variability (HRV) from electrocardiography (ECG) data
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in Anxiety Scores as determined by the Beck Anxiety Inventory (BAI)
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in Stress Scores as determined by Cohen's Perceived Stress Scale (PSS)
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in General Affect Scores as determined by the Positive and Negative Affect Scale (PANAS)
Time frame: Visit 1 and Visit 2 (6 weeks apart)
Changes in Stress Scores as reported on a 1-10 Likert Scale
Time frame: Visit 1 and Visit 2 (6 weeks apart)
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