Study reveals how gut microbes work with body clock in managing stress

A study has uncovered how microbes in one’s gut helps manage stress by interacting with the body’s circadian rhythms, or biological clock.

Researchers from the University College Cork, Ireland, found that the trillions of microorganisms in the gut — or the gut microbiome — control the hormones produced in response to stress in a time-dependent manner.

A healthy gut, thereby, helps in creating day-night rhythms in the production of stress hormones, whereas, a reduced gut microbiome leads to a disrupted body clock and is related to altered rhythms in how stress hormones are produced, the team said.

The findings, published in the journal Cell Metabolism, highlighted the importance of maintaining a healthy gut, they said.

The study’s results could also be looked into for developing treatments for mental conditions such as anxiety and depression, which are known to be linked to stress and often involve disrupted body clock and sleep cycles, the researchers said.

“Our research has revealed an important link between the gut (microbiome) and how the brain responds to stress in a time-specific way,” lead researcher John Cryan, University College Cork, said.

“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,” Cryan said.

For the study, the researchers looked at mice, which are known to have biological processes and genetic material similar to humans.

The team found an “intricate relationship” between the gut microbes and three regions in the brain forming the HPA axis — the hypothalamus, the pituitary gland and the adrenal gland. The HPA axis is the body’s central stress response system.

The researchers showed that a depletion of the gut microbiome results in an over-activation of the HPA axis in a manner specific to the time of the day. This, combined with changes to the brain’s regions responding to stress and the biological clock, leads to an altered body’s response to stress over the entire day, they said.

Specific gut bacteria, including a Lactobacillus strain (Limosilactobacillus reuteri), were identified as “key influencers” of this body clock-related stress response.