Gut bacteria affects stress response, UCC scientists find

6 Nov 2024

Prof John Cryan and Dr Gabriel Tofani. Image: Gerard McCarthy photography

The findings open the door for new microbial-based therapy for anxiety and depression, according to UCC.

A new study has uncovered the vital role gut health plays in regulating stress responses by interacting with the body’s circadian rhythms.

In a study published yesterday (5 November) in Cell Metabolism, scientists from University College Cork (UCC) and APC Microbiome Ireland – a Research Ireland Centre – offered evidence proving that the trillions of microorganisms in the gut control the body’s hormonal responses to stress in a time-dependent manner.

The study, which was conducted on mice, highlighted the connection between gut microbiota (the ecosystem of microorganisms living inside a host’s gastrointestinal system) and the hypothalamic-pituitary-adrenal (HPA) axis (the body’s central stress response system) demonstrating that a depletion in gut microbiota leads to hyperactivity in the HPA axis in a time-specific manner.

This, along with changes to the brain’s stress and circadian responding regions – regions that influence sleep, hormone release, appetite and body temperature – results in an altered stress response.

The research also found specific gut bacteria, including Limosilactobacillus reuteri – found in the human gastrointestinal tract and breast milk – as key influencers of the circadian-regulated stress mechanism.

The findings from this study allow for the development of new microbial-based therapies that could help individuals better manage stress-related mental health conditions, such as anxiety and depression, said UCC.

“Our research has revealed an important link between the gut microbiota and how the brain responds to stress in a time-specific way,” said principal investigator Prof John Cryan.

“The gut microbiome doesn’t just regulate digestion and metabolism, it plays a critical role in how we react to stress, and this regulation follows a precise circadian rhythm. These findings underscore the importance of maintaining a healthy microbiome, particularly for those living in today’s stressful and fast-paced environment.”

First author Dr Gabriel Tofani said: “Our work also demonstrates that exploring this relationship between the gut microbiota and circadian rhythms will be key in the development of microbiota-based therapies for the stress-related disorders in the future.”

Earlier last month, two women-led start-ups from UCC received a combined funding of more than €1m from Enterprise Ireland’s Commercialisation Fund to develop products aimed at women’s health and skin health with the help of the APC Microbiome Research Centre.

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Suhasini Srinivasaragavan is a sci-tech reporter for Silicon Republic

editorial@siliconrepublic.com