- Higher gut bacteria diversity links to greater hormonal and stress reactivity in adults
- Gut microbiome diversity supports flexible adaptation to acute stress challenges
- Study showed cortisol and subjective stress rise with increased microbial diversity
A higher diversity of the gut bacteria could be associated with a greater hormonal and stress reactivity, a study has found. Comprising microorganisms living in the gut, the gut microbiome contributes towards metabolism and function of the immune system, with research suggesting that it can modulate the body's stress response. A greater microbial diversity is often associated with a more stable and resilient microbial ecosystem and with a higher functional flexibility, which may contribute to an appropriate regulation of stress responses. However, "A stronger acute stress response is not necessarily detrimental. (An) appropriate activation of the stress system enables (a) flexible adaptation to challenges and threats. A greater diversity of gut bacteria, as well as certain metabolic products, could play a supportive role in this process," lead researcher Thomas Karner, psychologist at the University of Vienna in Austria, said.
Researchers said it has remained unclear until now whether differences in the human gut microbiome are actually associated with acute stress reactivity.
They showed for the first time that in healthy adults, the diversity of gut bacteria and their capacity to produce metabolites, including short chain fatty acids, are associated with an acute stress response -- particularly stress reactivity, the team said.
A higher microbial diversity was associated with a stronger hormonal and subjectively perceived stress reactivity, with the results, published in the journal Neurobiology of Stress, suggesting that the gut microbiome may play a role in regulating the acute stress response.
The study provides new evidence that the gut microbiome, and thus potentially also diet and lifestyle, is associated with how our bodies respond to stress, the researchers said.
Seventy four healthy adults either underwent a standardised stress test or performed a comparable, stress-free task (controls).
Stress hormones, such as cortisol, in saliva and subjective stress levels were measured and the gut microbiome analysed using stool samples.
The researchers also looked at the composition of the microbiome and estimated production capacity of short-chain fatty acids.
The authors "found that (a) higher gut microbial alpha diversity was associated with (a) higher cortisol and subjective stress reactivity across individuals of the stress group, but not in controls." Stress reactivity was associated with gut bacteria's capacity to produce different metabolic products -- a higher estimated capacity for production of 'butyrate' was associated with higher stress reactivity, whereas a higher 'propionate' production was associated with lower reactivity.
Butyrate and propionate are short-chain fatty acids produced by gut bacteria, which are involved in metabolic and immune processes and can also affect the brain.
The researchers suggested that the relationship between microbial metabolites and the acute stress response is more complex and cannot be reduced to a single direction.
(Except for the headline, this story has not been edited by NDTV staff and is published from a syndicated feed.)
