Probiotics in Psychosocial Stress and Anxiety. A Systematic Review

Abstract

Background and Aims: Recent mounting evidence suggest that probiotics supplementation can have a positive effect on mood and psychological symptoms such as stress and anxiety disorders. The majority of studies, however, rely on animal models, while clinical data are still inconsistent. In this systematic review, we examined if and to which extent probiotics can influence psychological stress and anxiety disorders.
 Methods: The search of online databases Medline, PubMed, Scopus, Web of Science and clinical trials.gov provided relevant studies up to November 2019. We included double blind, randomized and placebo controlled or prospective studies, as well as studies measuring preclinical psychological symptoms of perceived stress and anxiety, before and after supplementation with a probiotic.
 Results: Twelve studies met the inclusion criteria (3 on stress, 4 on anxiety, and 5 both on stress and anxiety), accounting for 1,521 participants. The improvement of stress, anxiety, and stress-anxiety was reported in 1/3, 3/4, and 2/5 studies, respectively.
 Conclusions: Available studies suggest that probiotics may improve psychological symptoms associated particularly with anxiety. Further research needs to investigate whether probiotics also improve psychological stress disturbances.

Lactobacillus rhamnosus CNCM I-3690 decreases subjective academic stress in healthy adults: a randomized placebo-controlled trial

“… 9 Moreover, a more artificial stressor (socially evaluated cold pressor test) was used, in contrast to a thesis defense by students in our study. Recent systematic reviews concluded that probiotics and particularly L. rhamnosus may improve anxiety in rodents, 5 , 6 and reasons for conflicting results may lie in the stressors used and subjects’ background. In this study, increased anxiety and perceived stress levels were found with the placebo, independently of the change in cortisol, pointing toward the strong anticipatory effect of public speech on behavioral and biological level.…”

“… 4 Indeed, recent systematic reviews suggested that some Lactobacillu s and Bifidobacterium strains may reduce anxiety and L. rhamnosus was identified as a potential anxiolytic species based on preclinical data. 5 , 6 L. rhamnosus JB-1, formerly referred to as L. reuteri , reduced depressive-like behavior in mice, 7 , 8 which was abolished after vagotomy. 7 However, these promising preclinical findings were not reproduced with L. rhamnosus JB-1 in healthy humans after a socially evaluated cold pressor test.…”

Gut Microbiota, Probiotics and Physical Performance in Athletes and Physically Active Individuals

“…Results from preclinical and clinical studies suggest that probiotic administration may have positive effects in mental responses [ 117 , 118 ]. Few studies have investigated the effects of probiotic supplementation on the cognitive outcomes of athletes or physically active subjects [ 84 , 93 , 112 ] ( Table 2 ).…”

Application of Enterococcus malodoratus SJC25 for the Manufacture of Whey-Based Beverage Naturally Enriched with GABA

“…Several studies have reported the ability of probiotics to alleviate psychological stress in humans and to exert anxiolytic effects in rats, contributing to a growing body of evidence that the gut microbiota can influence the nervous system [10][11][12]. Gamma-aminobutyric acid (GABA) is the main inhibitory neurotransmitter in the central nervous system and has been associated with beneficial health effects such as relaxing and calming effects, with a particular emphasis on the antihypertensive effect demonstrated in animal and human studies [13].…”