Probiotics can protect against the negative effects of stress but do not seem to work, if taken afterwards. http://www.sciencedaily.com/releases/2013/03/130314110256.htm Mar. 14, 2013 — For those with irritable bowel syndrome who wonder if stress aggravates their intestinal disorder, a new University of Michigan Health System study shows it's not all in their head. Researchers revealed that while stress does not cause IBS, it does alter brain-gut interactions and induces the intestinal inflammation that often leads to severe or chronic belly pain, loss of appetite and diarrhea. Stress has a way of suppressing an important component called an inflammasome which is needed to maintain normal gut microbiota, but probiotics reversed the effect in animal models, according to findings published online ahead of print in Gastroenterology. "The effect of stress could be protected with probiotics which reversed the inhibition of the inflammasome," says senior study author and gastroenterologist John Y. Kao, M.D., associate professor of internal medicine at the University of Michigan. "This study reveals an important mechanism for explaining why treating IBS patients with probiotics makes sense." Probiotics are live bacteria that help grow the gut-dwelling "good" bacteria that keep pathogens in check, aid digestion and nutrient absorption and contribute to immune function. U-M researchers including Chung Owyang, M.D., chief of the U-M Division of Gastroenterology, Gary Huffnagle, Ph.D., professor of pulmonary and critical care, and infectious disease expert Vincent Young, M.D., Ph.D., were able to identify the way stress significantly altered the composition of gut bacteria and the role of probiotics. Maintaining healthy microbiota requires action by nucleotide-binding oligomerization domain protein-like receptors, pyrin-domain containing (NLRP)-6 inflammasomes. But when stressed, mice produced corticotropin-releasing hormone (CRH) that prevented inflammasomes from doing their job. Inhibiting inflammosomes alters the composition of the gut, leading to intestinal inflammation. In the study, pretreatment with probiotic therapy reduced inflammation in mice with stress-induced small bowel inflammation. "Additional clinical study is required to determine the optimal probiotic therapy," says Kao. "Patients can start living healthier lifestyles to improve their gut microbiota such as adding more fruits and vegetables to their diet, and looking for ways to keep stress in check." EDIT: I just read parts of the study, they used "Bifidobacterium bifidum, Lactobacillus acidophilus, and Streptococcus faecalis". Moreover: "This effect [improvement of symptoms] was not observed when probiotics were administered after the initiation of WAS" This could mean, that taking probiotics after the inflammation already took place, may not lead to improvement? And another one: "The total bacterial load in the small intestine and colon were increased by 1.5 and 1.2 fold, respectively" This means, that the small intestine seems to be the place where the problems occur. Connection to SIBO? "WAS-induced intestinal pathology is associated with the inhibition of NLRP6 and additional insults (e.g., CRH-induced intestinal permeability) are required to induce the development of inflammation." Intestinal permeability seems to play an important role. Most GI doctors still have no clue about what role IP plays for disease and how to reduce it. "This CRH surge also increases intestinal permeability, leading to an increase in bacterial translocation" So corticosteroids can increase intestinal permeability? Probably dose dependent but interesting. "Moreover, we believe our results implicate NLRP6 as an important target in the development of a novel therapy for stressed-induced intestinal disorders" So we need something to increase NLRP6.