Immune System

The Immune System in the Digestive Tract

The huge surface area of the digestive tract has natural protection against injury from bad bacteria, viruses, parasites, and other toxins that may get into the digestive system with food or through other routes. The immune system is critical in helping the intestines respond to these threats. The challenge 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).

When a new food is introduced, the immune system decides whether or not to attack by causing inflammation and excess mucus production. If the immune system is continually challenged with messages to attack, the resulting inflammation of the digestive tube can, over time, lead to damage of the lining. Inflammation is chronic in diseases such as Crohn's disease and ulcerative colitis.

Although many people with IBS find that their symptoms worsen when they eat certain foods, these reactions are generally considered food intolerance and don't involve the immune system.