The Role of the Immune System in the Digestive Tract

Published date: March 15, 2012 | Modified date: October 3, 2019

A majority of your immune system is lining your digestive tract! The reason for this is that the digestive tract is incredibly vulnerable to insults from the outside world. The huge surface area of your digestive tract (about 30 feet long and if spread out would be the size of two tennis courts) must be protected against bad bacteria, viruses, parasites, and all types of toxins that may get into the digestive system by riding along with food or drink. And lets not forget all the stuff that drains down the back of your throat from your nose, mouth and sinuses. That gets down there too.

The immune system is critically important in helping the digestive tract respond to these challenges. And one of it’s major challenges is to correctly tell the difference between what is bad (such as viruses and bad bacteria) and what is good (such as nutrients and good bacteria).

Your immune system must determine whether or not to react to the things that you put into your mouth. Whenever you try a new food, it must decide, “Do I let this go or do I attack and kill it?” Sometimes it gets confused between food and bad guys, because you are always ingesting bacteria and other substances with your food, no matter how fresh and clean it is. When everything is working properly, the bad guys get eliminated and food goes free.

While your immune system will “okay” most foods, we don’t yet understand why the immune system reacts against some foods in some people. Medications such as antibiotics, GMOs, pesticides, and other chemicals likely impact this decision making process. Recent studies also suggest that your immune system’s ability to develop correct tolerance depends a great deal on the balance of good bacteria inside your intestinal tract.

When you put something into your digestive tube that the immune system doesn’t like, it attacks. And when the immune system attacks, that almost always results in inflammation and may result in mucus production. If your immune system is continually bombarded with messages to attack (by virtue of routinely ingesting a food that it doesn’t tolerate, then an ensuring pattern of chronic inflammation develops.

This inflammation can have major consequences. Inflammation in the digestive tract can lead to all kinds of damage. Some of it is obvious, like GERD and ulcerative colitis, and other types of inflammation are more visually subtle but often just as problematic, such as “leaky gut” in IBS.

For these reasons it is incredibly important for you long term health to correctly identify and avoid foods that are causing inflammation in your body. This will help you solve or prevent many health problems.