New findings reveal that the gut microbiome plays a significant role in managing the body’s daily stress hormone patterns. When gut bacteria are diminished, the brain’s natural circadian rhythm can become disrupted, leading to changes in stress hormone levels. This research emphasizes that gut microbes influence important brain areas responsible for stress management throughout the day. By transplanting microbes, researchers found that the daily variations in gut bacteria are essential for the regulation of stress hormone release.
A groundbreaking investigation has revealed the essential function of gut microbiota in controlling stress responses through its interaction with the body’s circadian rhythms.
The results of this study suggest new microbial-based treatments could assist people in effectively coping with stress-related mental health issues, like anxiety and depression, which often coincide with disruptions in sleep and circadian cycles.
This innovative research from University College Cork and APC Microbiome Ireland—part of Research Ireland—provides strong evidence that the vast array of microorganisms in the gut plays a critical role in how the body reacts to stress across different times of the day, creating opportunities for new treatment strategies that focus on the gut-brain connection.
Published in Cell Metabolism, this research highlights the complex interaction between gut microbiota and the hypothalamic-pituitary-adrenal (HPA) axis, which is the body’s main stress response system. The study shows that a reduction in gut microbiota can lead to an overactivity of the HPA-axis, which varies throughout the day. This, combined with changes in brain areas that respond to stress and circadian signals, leads to different stress reactions over the course of the day.
The research also identifies specific gut bacteria, including a strain of Lactobacillus (Limosilactobacillus reuteri), as crucial in this circadian-regulated stress process. L. reuteri was noted as a candidate that could alter glucocorticoid levels (stress hormones), linking normal daily fluctuations of the microbiota to changes in how the body responds to stress.
This important discovery paves the way for psychobiotic treatments aimed at enhancing mental health by targeting the gut bacteria that help regulate stress.
Impact and Implications
As modern lifestyles increasingly disturb circadian rhythms due to irregular sleep patterns, heightened stress, and unhealthy diets, this research emphasizes the integral role of gut microbiota in sustaining the body’s natural stress regulation mechanisms.
Commenting on the research, Principal Investigator Professor John Cryan said,
“Our findings have uncovered a pivotal relationship between the gut microbiota and the brain’s stress responses that is time-specific. The gut microbiome does more than just aid digestion and metabolism; it is vital for our stress reactions, following a precise circadian rhythm. These insights highlight how crucial it is to maintain a healthy microbiome, especially for those navigating the challenges of today’s fast-paced and stressful lives.”
First author Dr. Gabriel Tofani added, “Our research emphasizes not only the makeup of gut microbiota but also its daily fluctuations. By demonstrating that gut bacteria affect how the body copes with stress throughout the day, we shed light on the mechanisms through which the microbiota influences our interactions with the environment. Understanding this relationship between gut bacteria and circadian rhythms is essential in developing microbiota-based therapies for stress-related disorders in the future.”
“This research marks a significant advancement in our understanding of how the microbiome influences mental health,” shared Professor Paul Ross, Director of APC Microbiome Ireland. “At APC, we are dedicated to exploring the diverse ways our gut microbiome affects human health, and this study offers critical insights into how targeting specific bacteria could assist in managing or even preventing stress-related issues. The prospects for enhancing mental health through microbiome-based treatments are very promising, and this study brings us closer to that aspiration.”
The research was performed at APC, a world leader in microbiome research located at University College Cork. Professor Cryan’s team has been pioneering gut-brain axis studies, and this new discovery contributes to the growing evidence that gut bacteria play significant roles in both mental and physical health.
