Research

Hormonal

Specific gut microbiota strains (e.g., Lactobacillus, Bifidobacterium) and their metabolites (SCFAs, neurotransmitters) regulate the Hypothalamus-Pituitary-Adrenal (HPA) axis and stress response, with germ-free animals showing exaggerated stress hormone release that is reversed by microbial colonization.

Your gut bacteria talk to your brain and stress system. Studies show that without gut bacteria, stress responses are exaggerated. You can support your mental resilience and stress handling by consuming probiotics (like Lactobacillus and Bifidobacterium) and prebiotics. These microbes help regulate your stress hormones and produce neurotransmitters that calm the nervous system.

ModerateSupportsMEDIUM confidence
In GF mice, a mild restraint stress induced an exaggerated release of corticosterone and ACTH compared to the specific pathogen free (SPF) controls, thus elucidating a connection between the gut microbiota and HPA axis [46].
Allison Clark et al. · Journal of the International Society of Sports Nutrition · 2016

Why this rating

Based on murine models (germ-free mice); human data is observational or mechanistic (probiotic effects on cortisol) but less definitive for causality in stress response.

Source

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Allison Clark et al. · Journal of the International Society of Sports Nutrition · 2016

DOI 10.1186/s12970-016-0155-6

systematic_reviewCited 561×
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DOI resolved against Crossref · corpus check 2026-06-10

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