Plain language summary
Physiological and psychological stress can affect gut function and its interaction with the brain (gut-brain axis). Different types of stress and different phases of stress regulation can affect the brain in different ways. Manipulation of the gut microbiota using probiotic bacteria has been shown to improve cognition and stress response. However, probiotic interventions are likely to have different effects depending on the strains used. The aim of this study was to assess the effects of a probiotic intervention on brain activity and stress response. This study is a randomised double-blinded placebo-controlled crossover study with 22 healthy subjects. Subjects were randomised to two study groups receiving the intervention in different orders (probiotics or placebo first). Results demonstrate that the probiotic intervention: - altered activity in specific brain regions known to regulate emotion and stress response. - significantly altered functional connectivity between the upper limbic and medioventral regions. - did not affect the activation of other limbic or subcortical areas. Authors conclude that their findings could further lead to possible clinical implications for improving stress resilience and potential roles in the treatment of affective and gut-brain axis disorders.
Abstract
Probiotics are suggested to impact physiological and psychological stress responses by acting on the gut-brain axis. We investigated if a probiotic product containing Bifidobacterium longum R0175, Lactobacillus helveticus R0052 and Lactiplantibacillus plantarum R1012 affected stress processing in a double-blinded, randomised, placebo-controlled, crossover proof-of-concept study (NCT03615651). Twenty-two healthy subjects (24.2 ± 3.4 years, 6 men/16 women) underwent a probiotic and placebo intervention for 4 weeks each, separated by a 4-week washout period. Subjects were examined by functional magnetic resonance imaging while performing the Montreal Imaging Stress Task (MIST) as well as an autonomic nervous system function assessment during the Stroop task. Reduced activation in regions of the lateral orbital and ventral cingulate gyri was observed after probiotic intervention compared to placebo. Significantly increased functional connectivity was found between the upper limbic region and medioventral area. Interestingly, probiotic intervention seemed to predominantly affect the initial stress response. Salivary cortisol secretion during the task was not altered. Probiotic intervention did not affect cognitive performance and autonomic nervous system function during Stroop. The probiotic intervention was able to subtly alter brain activity and functional connectivity in regions known to regulate emotion and stress responses. These findings support the potential of probiotics as a non-pharmaceutical treatment modality for stress-related disorders.
Methodological quality
Jadad score
:
5
Allocation concealment
:
Yes
