A study conducted by researchers at the University of Vienna has found that a higher diversity of gut bacteria is associated with a stronger hormonal and subjective stress response. The research, published in the journal Neurobiology of Stress, involved 74 healthy adults who either underwent a standardized stress test or participated in a stress-free task. The researchers measured stress hormones, such as cortisol, in saliva and analyzed gut microbiome composition through stool samples. They discovered that individuals with greater gut microbial diversity exhibited higher cortisol levels and perceived stress during the stress test. Notably, the study identified that the gut microbiome's capacity to produce short-chain fatty acids, specifically butyrate and propionate, plays a significant role in stress reactivity. While higher butyrate production was linked to increased stress reactivity, higher propionate levels were associated with lower reactivity. These findings suggest that the gut microbiome may influence the body's stress response, emphasizing the importance of diet and lifestyle in stress management.