What Is the Gut Barrier? (plus, how care for it)

What Is the Gut Barrier? (plus, how care for it)

You’ve probably heard the phrase “trust your gut,” a metaphor which refers to the wisdom of having confidence in your intuition when trying to make a decision. Even non-metaphorically, you trust your gut on a daily basis to keep you protected from diseases, viruses, and infections. More specifically, you count on your gut barrier to maintain a healthy immune system so you can ward off all kinds of ailments.

How the Gut Barrier Works

The gut barrier is the informal name for the innermost layer of your large intestine called the mucosa. Like the epidermis, dermis, and hypodermis that make up your skin, the intestinal barrier is also comprised of multiple layers. The three outer layers of the gut, the serosa, muscularis and submucosa, play a greater role in the physical protection of the large intestine, but it is the mucosa where most of the microscopic-level battles against illness-carrying invaders take place.

The mucosa consists of several strata as well. The muscular intestinal wall is the outermost layer and is largely responsible for the physical contraction of the intestine in order to help propel bodily waste toward the rectum and eventually out of the body. The lamina propria is a layer of loose connective tissue which hosts many of the immune system’s cells that can attack and destroy disease-causing (also known as pathogenic) microorganisms.

But where most of the microbial activity takes place is in the epithelium, which is the final solid layer of the gut. Think of the epithelium as the “gate” to the inside of the intestine; its porous structure is designed to allow nutrients, electrolytes and other helpful microbes in while keeping inhospitable organisms out. Finally, the epithelium is coated with a thick mucus layer where antibodies and many other pathogen-fighting cells are manufactured.

When operating properly, the mucosa can repel or destroy toxins, viruses and unhealthy bacteria, while facilitating the intake of nourishing and beneficial microbes. But when these gut processes malfunction, the intestine can become inflamed, prevent proper immune system response, and allow unhealthy immune reactions to occur. So what can we do to preserve the health of our gut barrier?

Probiotics and Gut Health

The easiest and most straightforward solution is to incorporate more probiotics into our diet. Probiotics are bacterial organisms that are healthy for the digestive tract as well as the rest of the body. These “friendly” bacteria help sustain the delicate balance of the gut microbiome (the collection of active bacteria) by keeping “unfriendly” bacteria in check.

Different probiotic strains are capable of stimulating different internal processes that serve to safeguard the body’s overall health. Perhaps most importantly, probiotics have the ability to produce cells that are the building blocks for antibodies. Even better, probiotics can help stimulate the secretion of the antibodies in the mucus layer so that they are better able to attack pathogens. Antimicrobial substances that can eliminate “unfriendly” bacteria can also be created by probiotics.[1]

In addition, probiotic activity can strengthen the gut barrier itself. Some strains catalyze the construction of proteins which can form tight junctions that bond with epithelial cells to further prevent harmful microorganisms from breaking through.[2] Similarly, probiotics themselves can bind with these epithelial cells so there is no room for unhealthy toxins or pathogens to colonize these cells – much like taking up all of the available seats in a movie theater.[3]

There are other ways in which probiotics can bolster the immune system in the gut. The thick mucus layer on the epithelium can be fortified by specific probiotics which increase the secretion of the mucus itself.[4] Other probiotic strains have the power to alter the pH level in the gut by manufacturing acetic or lactic acid. As a result, harmful microbes, such as the dangerous E. coli bacterium, find it much more difficult to survive and thrive.[5]

How Do Prebiotics Help?

It’s important to note that even a favorable gut environment can take its toll on probiotics, which can lose their efficacy or even die off. So it’s essential to help your gut maintain adequate levels of probiotics in order to keep your immune system humming along.

How can you accomplish this? By providing fuel for the probiotics in the form of prebiotics. Unlike probiotics which are active bacteria, prebiotics are plant fibers that cannot be digested, incapacitated or killed by the intestinal tract. Instead, they serve as food for the probiotic bacteria (much like the fertilizer for a grassy lawn), which ferment the prebiotics into what are known as short-chain fatty acids. These not only enable the aforementioned tight junctions with epithelial cells throughout the large intestine, but they also act as a source of energy for the epithelial cells that line the colon.[6]

Both probiotics and prebiotics can be added to your diet through readily available over-the-counter supplements. Plus, they occur naturally in a number of foods (e.g. sauerkraut, kimchi, and kefir for probiotics; artichokes and bananas for prebiotics). Not only can these two types of gut flora help regulate digestive activity (You may visit activatedyou to have better understanding on digestive activity), but they also play a huge role in boosting your immune system so you can remain healthy and illness-free.

[1] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC1728100/

[2] https://www.ncbi.nlm.nih.gov/pubmed/26122786

[3] http://ajpgi.physiology.org/content/298/6/G807

[4] http://ajpgi.physiology.org/content/ajpgi/292/1/G315.full.pdf

[5] http://www.sciencedirect.com/science/article/pii/S0168160501004652

[6] http://stke.sciencemag.org/content/8/378/ec135