(OR WHAT HAPPENS IN VAGUS STAYS IN VAGUS)
We have a plethora of brain-like organs. We also have this other thingy called gut health which has its share of mental-emotional effects. In fact, researchers have a term they use called the microbiome–gut–brain axis. As the term implies it means that our intestinal flora affects the gut which in turn influences the brain through several possible mechanisms. One route is through the large coaxial cable called the vagus nerve which connects the entire GI system directly with the brain. It appears to be one of the ways the microbiome “speaks” to the brain.
It also involves the brain’s valium-like receptor class called the gamma aminobutyric (GABA) system. The GABAergic system has been recently implicated in the pathogenesis of anxiety and depression. Chronic colitis in humans is apparently associated with a much greater incidence of anxiety. Bercik et al found that certain populations of bacteria could reduce anxiety in mice that had chronic colitis as long as they had an intact vagus nerve. This contradicts the old saying that what happens in the vagus nerve stays in the vagus nerve. According to Bravo et al, when the microflora is disrupted and imbalanced with the overgrowth of harmful bacteria or yeast (called dysbiosis) it can markedly affect people or lab mice causing symptoms like anxiety. They concluded by saying:
…these findings highlight the important role of bacteria in the bidirectional communication of the gut-brain axis and suggest that certain organisms may prove to be useful therapeutic adjuncts in stress-related disorders such as anxiety and depression.
Indeed combinations of probiotics are already formulated that have anxiolytic, Valium-like effects in human volunteers. One formula was used in a double-blind, placebo-controlled, randomized parallel group study with probiotic formula (PF-L. helveticus R0052 and B. longum R0175) administered for 30 days resulted in alleviated psychological distress… and other beneficial psychological effects in healthy human volunteers.
It goes much further however. Philip Burnet published an article in the Proceedings of the National Academy of Sciences in 2012 entitled: Gut bacteria and brain function: The challenges of a growing field. In this paper he points out that other investigators have shown that there are possibly gut-derived neuroactive substances working outside the vagus nerve probably in the bloodstream. Furthermore, additional work has shown that the microbiome affects things like spatial memory, problem solving abilities, treating seizure disorders and anxiolysis. He concludes by saying:
Bacterial gene profiling by the Human Microbiome Project at the National Institutes of Health has been active since 2008 and promises to yield sufficient information to allow such comparisons [of different classes of beneficial bacteria] to be made.
In summary, investigations into the microbiome–gut–brain axis have already yielded compelling evidence for the link between gut bacteria proliferation and brain function.
In fact, the gut may emerge as the single most important health factor in the entire field of preventive medicine. Consider the fact that we, as a modern species, may have lost much of our intestinal biodiversity (EO Petrof et al) from our cave man past which had no refrigeration, no antibiotics, no chlorinated water, all babies breast fed, all babies vaginally delivered (as opposed to about 25% or more from Cesarean section), and eating unrefined, mainly raw or fermented foods free of antibiotics.
DYSBIOSIS AND AUTISM
There is increasing evidence for the involvement of the gut microbiota in regressive autism. As we have seen above microbial dysbiosis has been shown to alter the behavior of laboratory animals and human volunteers, while the subsequent treatment with specific probiotic formulas relieves those symptoms. This is an important concept that is finally being investigated and brought to the forefront by many doctors. One such person is Dr. Natasha Campbell-McBride. Allegedly McBride was able to “cure” her son of autism to the point where he literally lost the diagnosis of autism. Dr McBride is a neurologist with a practice in the UK where she treats patients with autism, learning disabilities, neurological and psychiatric diseases, along with immune and digestive disorders. I believe it’s possible to significantly help those suffering from ASD by changing diet and gut milieu. I don’t know about curing autism this way. However, more and more cases are appearing in the literature. A casual glance through PubMed reveal dozens of studies on this and related subjects. I am providing some of these below. Dr Wakefield has had similar case reports where autistic children put on a gluten free diet, vastly improved to the point where some of them can no longer meet the diagnostic criteria of autism. Back in the mid-nineties he reported on this association. These kids had autism and inflammatory bowel disease together which has recently been corroborated by others (Parracho et al., 2005). They improved considerably once they were put on the proper anti-inflammatory medications for their GI tracts. Autistic kids often have altered urinary metabolites characteristic of altered gut microbiota. At least six studies have been done that demonstrate autistic children have considerable gut dysbiosis. This has led some to theorize for a bacterial toxin-medicated disease (Bolte, 1998; Finegold, 2011b). Further evidence for a gut-brain pathology comes from the use of oral vancomycin (a powerful antibiotic used to treat some types of severe dysbiosis) in a group of severely autistic children. They reported impressive developmental gains during treatment that diminished when the drug was withdrawn.
Who would have thought that your brain function and emotions can be drastically influenced by your gut microbiome? Twenty years ago you would have been burned at the stake for claiming this.
In an interview Dr McBride shares her insights about Gut and Psychology Syndrome (GAPS), which can make a child particularly prone to vaccine damage, and the GAPS Nutritional program; a natural treatment for autism, ADHD, dyslexia, dyspraxia, depression and schizophrenia.
What happens in these children [is that] they do not develop normal gut flora from birth…Gut flora is a hugely important part of our human physiology. Recently research in Scandinavia has demonstrated that 90 percent of all cells and all genetic material in a human body is our own gut flora. We are just a shell… a habitat for this mass of microbes inside us. We ignore them at our own peril.
…As a result, their digestive system—instead of being a source of nourishment for these children—becomes a major source of toxicity. These pathogenic microbes inside their digestive tract damage the integrity of the gut wall. So all sort of toxins and microbes flood into the bloodstream of the child, and get into the brain of the child. That usually happens in the second year of life in children who were breast fed because breastfeeding provides a protection against this abnormal gut flora. In children who were not breastfed, I see the symptoms of autism developing in the first year of life. So breastfeeding is crucial to protect these children.
 Bravo JA, Ingestion of Lactobacillus strain regulates emotional behavior and central GABA receptor expression in a mouse via the vagus nerve. Proc Natl Acad Sci U S A. 2011 Sep 20; 108(38):16050-5.
 Proc Natl Acad Sci U S A. 2012 January 24; 109(4): E175. Published online 2012 January 13.