Foreign Gut Bacteria Strike a Deal for Peaceful Co-existence

Our digestive tracts accommodate as many foreign cells¹ as we have cells in our own body.  This relationship has existed since the beginning of human evolution.  We now have tools to explore communication between gut contents and human cells, a truly new frontier in health.  One way that gut health is maintained is through a negotiated peace arrangement between the various populations of types of bacteria and the human immune system.  That agreement can be shattered by poor diet, too much stress, or antibiotics.  The peaceful bacteria can then take on the attributes of a hostile gang, the human immune system responds, and an inflammatory battle ensues.  This can lead to irritable bowel, obesity, diabetes, or colon cancer.   

“The bacteria appear to have struck a deal with their host,” Sarkis K. Mazmanian, assistant professor of biology at Caltech Mazmanian says. They keep their own numbers low so they don’t overwhelm the immune system, and in return, the immune system leaves them alone. “The bacteria need the secretion system to put the host in ‘don’t attack’ mode.” In return, the presence of the bacteria does not induce inflammation, as would be the case with a pathogen that has not evolved a similar “agreement.”
“There has to be communication. It could be peaceful—as is the case for symbionts—or it could be an argument—as is the case for pathogens. But when this molecular dialogue breaks down, it’s probably harmful to both microbe and man,” Mazmanian says.  “Inflammation leads to cancer.”

One strategy to help keep your gut in balance is to use probiotic supplements of friendly flora, ensuring your good guys have a relative numbers advantage.  This is especially important if you have ongoing digestive symptoms or have used antibiotics.