The ability of gut microbiota to communicate with the brain and thus modulate behavior is emerging as an exciting concept in health and disease. Specific modulation of the enteric microbiota may be a useful strategy for stress- related disorders and for modulating the co-morbid aspects of gastrointestinal disorders such as irritable bowel syndrome and inflammatory bowel disease. The bidirectional signaling between the gastrointestinal tract and the brain is vital for maintaining homeostasis and is regulated at the neural (both central and enteric nervous systems), hormonal and immunological levels. Perturbation of these systems results in alterations in the stress-response and overall behavior.

6th Probiotics, Prebiotics & New Foods Congress, in Rome, on September 11 th -13 th 2011 “Behaviour can be changed by transferring gut microflora from one person to another.” This is the astonishing conclusion of a Canadian experiment conducted on mice as part of a research program investigating the microflora-gut-brain axis and the effects microflora change can have on the brain. This and other new studies was presented by Professor S. Collins, from McMaster University (Ontario, Canada)

Assessment of psychotropic-like properties of a probiotic formulation (L. helveticus R0052 and B. longum R0175) in rats and human subjects Conclusion These results provide further evidence that gut microflora play a role in stress, anxiety and depression, perhaps via the enteric nervous system as well as centrally. Subject to the confirmation of these results, probiotics might offer a useful novel therapeutic approach to neuropathological disorders and/or as adjunct therapies in psychiatric disorders. Michael Messaoudi et al. British Journal of Nutrition (2011), 105, 755–764