Tuesday, February 19, 2013

Gut Microbes: Protectors of the GI Tract

Gut flora, and the associated probiotics used to supplement them, help the body function properly in a variety of ways. Sometimes, though, the method of assistance is counterintuitive. You may already know that microbes in the gut can aid in protecting the gastrointestinal (GI) tract from harmful infection. But, one of the major reasons why may surprise you.

The beneficial bacteria of the gut do a good job of keeping out harmful, or pathogenic, bacteria by, to put it simply, taking up the prime real estate and eating all the good food. In the gut, there is a limited amount of space that can be occupied along the epithelial cells lining the inside of the intestines. Access to this lining is essential to bacteria because the transferal of wastes and nutrients between the inside and outside of the intestines occurs here. Thus, it is a major gateway between the GI tract and the rest of the body. Probiotic bacteria occupy the space along the lining, preventing harmful bacteria from gaining access to this gateway. Without helpful flora occupying these spaces, potentially harmful species could gain easy access to the nutrient-rich areas of the body which would allow them to thrive.

Gut flora also keeps pathogens from gaining access to nutrients in another way. Most probiotic bacteria establish a symbiotic relationship with the host (our body). In this relationship, the bacteria perform essential regulatory and nutrient production processes for the body, and the body does the same for the bacteria, thus creating a positive environment for both organisms. Because of this relationship, the body and the bacteria have developed ways to signal their needs to one another. The bacteria can tell the body, via chemical signals, when to produce more of the nutrient which the bacteria needs, and when to produce less. This signaling process prevents overproduction of the nutrient. And, because pathogenic bacteria often need the same nutrient to survive, the pathogen is prevented from gaining access to any excess food.

In this context, the activity of the bacteria through these two processes is called the barrier effect. It exemplifies the principle of competitive exclusion, whereby two organisms competing for identical resources cannot coexist. It is, in essence, one organism being crowded out by another, fitter organism. Since the body favors the symbiotic probiotic bacteria, the good bacteria have a leg up in the competition.

Unfortunately, the body can sometimes be stripped of the gut flora which it has grown accustomed to, making the body vulnerable to pathogens. This is where a probiotic supplement, such as PRO EM-1, can be helpful. PRO EM-1 contains symbiotic microorganisms beneficial to the body which can restore the balance of gut flora in the GI tract. For more about the relationship between microorganisms and the GI tract, check out Guarner and Malagelada’spaper on the subject.