From Gary Sharpe
DIRECT LINK BETWEEN VAGUS NERVE DYSREGULATION AND GUT MICROBIOME IMBALANCES
This is a very important article, in my view, because it points to something I’ve felt true for a while: that imbalances in gut microbiome, much purported to be the principal underlying reason for illnesses currently, are just as much an effect of nervous system dysregulation/chronic illness as a cause. In particular, this science review article draws the important bi-directional arrows between Vagus Nerve dysfunction and gut biome disruption, while also pointing to stress/trauma being the principle causative mechanisms for both:
“The microbiota, the gut, and the brain communicate through the microbiota-gut-brain axis in a bidirectional way that involves the autonomic nervous system. The vagus nerve (VN), the principal component of the parasympathetic nervous system, is a mixed nerve composed of 80% afferent and 20% efferent fibers. The VN, because of its role in interoceptive awareness, is able to sense the microbiota metabolites through its afferents, to transfer this gut information to the central nervous system where it is integrated in the central autonomic network, and then to generate an adapted or inappropriate response. A cholinergic anti-inflammatory pathway has been described through VN’s fibers, which is able to dampen peripheral inflammation and to decrease intestinal permeability, thus very probably modulating microbiota composition. Stress inhibits the VN and has deleterious effects on the gastrointestinal tract and on the microbiota, and is involved in the pathophysiology of gastrointestinal disorders such as irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD) which are both characterized by a dysbiosis. A low vagal tone has been described in IBD and IBS patients thus favoring peripheral inflammation. Targeting the VN, for example through VN stimulation which has anti-inflammatory properties, would be of interest to restore homeostasis in the microbiota-gut-brain axis.”
“The role of the VN in microbiota-brain communication is now well-established. A reduction in vagal tone reflecting dysautonomia has been shown in IBS and IBD characterized by a leaky gut and dysbiosis. Consequently, monitoring vagal tone would be an interesting marker of the microbiota-gut-brain axis. Relevant electrophysiological data could be then considered as a part of the—omes, and should be integrated in a converging combined approach to decipher complex IBD and IBS pathophysiology. Moreover, monitoring and targeting vagal tone through VNS, microbiota modulation (using prebiotics, probiotics, fecal microbiota transplantation, diet…), drugs targeting the cholinergic system and/or complementary medicine (hypnosis, meditation), cognitive behavioral therapies, deep breathing, and moderate and sustainable physical activity would be of interest to restore a homeostatic microbiota-gut-brain axis.”
On the topic of monitoring Vagus Nerve health, I have also recently stumbled on the use of ultrasonography as a practical way to measure this, as well as electrophysiology mentioned above, and this may hold a key part of the diagnostic process in the near future. I will report on this more fully in separate post.
Source: Frontiers | The Vagus Nerve at the Interface of the Microbiota-Gut-Brain Axis | Neuroscience