From: rpattree2@gmail.com   
      
   Microbes in our stomachs may be making us miserable - New research suggests   
   that certain kinds of stomach bacteria may be the source of our anxiety and   
   depression   
      
      
      
   SUNDAY, APR 27, 2014 07:00 PM CDT    
      
   Gut check: Microbes in our stotmachs may be making us miserable    
      
   New research suggests that certain kinds of stomach bacteria may be the source   
   of our anxiety and depression    
      
   JILL RICHARDSON, ALTERNET    
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   TOPICS: ALTERNET, MICROBES, DEPRESSION, ANXIETY, LIFE NEWS    
      
   Gut check: Microbes in our stomachs may be making us miserable    
   This article originally appeared on AlterNet.    
   AlterNet Microbes are in the news these days. Specifically, the microbes that   
   live in and on the human body, making up our "microbiome." Michael Pollan made   
   a splash with a column titled "Some of My Best Friends are Germs" about a year   
   ago, and now    
   Martin Blaser, director of the Human Microbiome Project at NYU, has published   
   a book called Missing Microbes: How the Overuse of Antibiotics Is Fueling Our   
   Modern Plagues.    
   In a short period of time, bacteria, fungi and other microbes have gone from   
   enemy to friend in the public consciousness.    
   But in addition to the many studies finding out about the numbers and   
   diversity of the microbes with whom we share our bodies and their roles in our   
   nutrition and immune function, some researchers have made some surprising   
   findings: the bugs in your gut    
   might actually impact your emotions.    
   The bidirectional connection between our brains and our guts is not news. When   
   we are hungry, full, queasy, or suffering from gas or constipation, our guts   
   let our brains know. And our emotions can easily impact how we feel in our   
   guts, like when one has    
   "butterflies in the stomach." The link between emotions and the gut is so   
   strong that we talk about "gut instinct" or gut feelings.    
   What's more, the human gut is connected to the brain by the vagus nerve.   
   Within our guts, we have what is called the "enteric nervous system" (ENS),   
   which is so significant it is often referred to as a "second brain."    
   Premysl Bercik, an associate professor of gastroenterology at McMaster   
   University, is one scientist on the forefront of researching the link between   
   gut and emotions. He began by studying low-grade gut inflammation in patients   
   with bowel disorders like    
   irritable bowel syndrome (IBS) and functional dyspepsia. "These are basically   
   patients who do not have any structural abnormalities but their gut   
   misbehaves," he explains. Over the years, his research drifted to studying how   
   microbiota impact gut    
   function and "from there it was only a step" to look at how they impact   
   emotions.    
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   Researchers like Bercik made the leap because a significant portion of their   
   patients suffer from psychiatric co-morbidities like anxiety and depression.   
   Was there a link between what was happening in their guts and what was   
   happening in their brains?    
   And, if so, what was it? Could it be that a person with a constant tummy ache   
   feels extra anxiety simply because he or she feels lousy all the time? Or is   
   it something more than that?    
   As early as 2004, scientists questioned whether probiotics might benefit   
   patients suffering from major depression. As a 2009 journal article put it,   
   "While evidence is still limited in psychiatric illnesses, there are rapidly   
   coalescing clusters of    
   evidence which point to the possibility that variations in the composition of   
   gut microbes may be associated with changes in the normal functioning of the   
   nervous system." In other words, we know there might be something there, but   
   we don't know enough    
   about it just yet.    
   Bercik was among those who wanted to know more. He and his team "began looking   
   at communication between gut and brain, how it can impact function of host and   
   what is the role that microbiota plays in all of this."    
   Several animal studies by Bercik and others showed that acute and chronic gut   
   inflammation resulted in changes in behavior and central nervous system   
   biochemistry, although scientists could not yet explain how or why. In 2010,   
   Bercik and others published    
   a study (funded in part by the food conglomerate Nestlé) that found that "mild   
   gut inflammation caused by chronic parasitic infection... induces anxiety-like   
   behavior in mice."    
   The next year, 2011, brought more revelations. One study compared conventional   
   and germ-free mice, finding behavioral and brain chemistry differences between   
   the two groups. That year, Bercik was among a team that published a study with   
   fascinating    
   findings showing how gut microbes impact behavior in mice. (This study was   
   also funded in part by Nestlé.)    
   They began with two different types of mice, Balb/c and NIH Swiss. Balb/c mice   
   are traditionally timid and exhibit anxiety-like behavior, whereas NIH Swiss   
   mice are known for being daring and adventurous. In addition to differing in   
   behavior, these types    
   of mice also differ in the composition of their gut microbes.    
   The scientists raised control mice of each type as well as germ-free mice of   
   each type. When the mice reached adulthood, they colonized some of the Balb/c   
   germ-free mice with normal Balb/c mouse gut microbes and they colonized   
   another group with typical    
   NIH Swiss mouse gut microbes. They did the same with the germ-free NIH Swiss   
   mice.    
   When "we colonized [them] with their own microbiota," explains Bercik, they   
   "basically reproduced the same behavior in the normal conventional mice."   
   Balb/c mice remained timid, and NIH Swiss mice remained daring "with a high   
   exploratory drive."    
   But when they colonized the Balb/c mice with NIH Swiss microbes, "they became   
   more daring, their exploratory behavior increased. And the opposite happened   
   with the other." NIH Swiss mice colonized with Balb/c mouse microbes became   
   more timid and anxious.    
   "Which would suggest that gut microbiota modulates or has an effect on   
   behavior," concludes Bercik. He adds that genetic background plays a role too,   
   but "changing the composition of gut bacteria shifted the behavior phenotype   
   in one or the other    
   direction."    
   Behavioral changes were also accompanied by changes in brain markers "in the   
   area of the hippocampus, which impacts your behavior and emotions," Bercik   
   adds.    
      
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