Stress can directly affect our gut bacteria, killing the good guys so the bad guys can take over, encouraging Crohn's and UC.
www.ncbi.nlm.nih.gov/pubmed/21040780stressor exposure impacts the stability of the microbiota and leads to bacterial translocation...
Stressor exposure significantly changed the community structure of the microbiota, particularly when the microbiota were assessed immediately after stressor exposure.
Most notably, stressor exposure decreased the relative abundance of bacteria in the genus Bacteroides, while increasing the relative abundance of bacteria in the genus Clostridium.
The stressor also increased circulating levels of IL-6 and MCP-1, which were significantly correlated with stressor-induced changes to three bacterial genera (i.e., Coprococcus, Pseudobutyrivibrio, and Dorea).