The trillions of microbes in the gut, called microbiome, are particularly sensitive to the effects of stress, according to new research from APC Microbiome Ireland at University College Cork.
UCC researchers analysed the gut microbes of both stressed mice and university students undergoing exams, to see if stress triggered changes in the gut bacteria.
This new study may hold the key to developing new approaches to managing stress and improving wellbeing, researchers say.
New strategies relating to gut health, such as dietary or supplement-based strategies, could be used to help alleviate the effects of stress in the future.
The research has been published in the journal Psychoneuroendocrinology, and the Cork research group show for the first time that the movement in the composition of the microbiome correlates with stress response.
The research was based on the concept of volatility, meaning the gut microbiome is not a static entity and is constantly changing with time.
For the study, Thomaz Bastiaanssen, a bioinformatician, John Cryan and Ted Dinan joined forces with neuroscientist Anand Gururajan, a post-doc researcher, to investigate if stress-induced changes in volatility were related to other biological and behavioural factors.
Mice were put under chronic psychosocial stress to investigate this theory.
The researchers used a combination of bioinformatic and biological approaches to demonstrate that higher changes occurred in the gut microbes of the stressed mice, compared to control animals who were not under stress.
They went on to show that this shift in the microbiome correlated with several other stress-sensitive variables, including stress hormones.
The research claims that this opens up the possibility that volatility, or monitoring changes in the gut microbes, could be a completely new way of examining the impact of stress on the body.
The researchers then investigated if the findings translated to humans.
They collected, sequenced and analysed gut microbiome samples and the levels of stress hormone levels in undergraduate university students before and after the exam period.
The data from these studies confirmed the data from the mouse work, suggesting that changes in gut bacteria due to stress was a common phenomenon across species.
These studies have wide-reaching implications, says Prof. John F Cryan, lead author on the study.
"We now have a novel way to examine the consequences of stress on the microbiome.
"This will hopefully give us a biomarker that will enable the development of microbiome-targeted strategies, what we have coined ‘psychobiotics’ that modulate the degree of volatility that occurs in stress."
However, the UCC team say more research is needed to develop such strategies, which will be dietary or supplement-based approaches.