This is a PDF link that is read only, unless you have the full PDF software. Worth a read. Brain–gut–microbiota axis—mood, metabolism and behavior
Timothy G.Dinan and John F.Cryan
In 2016, key studies have increased our understanding of the part played by the brain–gut–microbiota axis in disorders as diverse as depression, obesity and autism spectrum disorder. The data indicate that alterations in gut-microbial composition can substantially affect central physiology, and that transplantation of the gut microbiota can transfer a behavioural or physiological phenotype.
The association of alterations in gut–brain interactions with functional bowel disorders, chronic abdominal pain syndromes and even eating disorders has become increasingly clear in the past few years. Modulation of gut–brain-axis function is associated with alterations in the stress response and over-all behaviour in both animal models and in humans 1. A high comorbidity exists between stress-related mental symptoms such as anxiety and IBS, a fact that has provided the greatest impetus for research into the importance of the gut–brain axis2. Over 50% of patients with IBS have comorbid depression or anxiety. Modulation of the gut–brain axis is increasingly being proposed as an appropriate target for the development of novel treatments for a wide variety of disorders that range from depression and anxiety to IBS, obesity and
neurodevelopmental disorders 3.
The gut microbiota interact with the host through immune, neuroendocrine and neural pathways 4. These pathways arecomponents of the brain–gut–microbiota axis and preclinical evidence suggests that the microbiota can recruit this bidirectional communication net-work to modulate brain development, function and even behaviour. Preliminary studies have shown differences in the composition of the gut microbiota in patients with depression compared with healthy individuals.