The gut’s role in nutrition and a healthy immune system
A healthy gut microbiome supports food digestion and helps nourish the body by extracting and metabolizing nutrients from the food we eat. In addition, important vitamins, such as biotin and vitamin K, are produced in the gut flora (bacteria and other organisms that reside in the gut). Consequently, people with an unhealthy gut microbiome may suffer from malnutrition and related health issues.
The gut is often referred to as the second immune system, which makes sense because 70 percent of the immune system resides in the intestinal tract. A healthy gut microbiome with the right balance of gut flora and a semipermeable (not leaky) intestinal wall are essential for a strong immune system.
An overabundance of bad bacteria and leaky gut can lead to inflammation in the gut and throughout the body. Inflammation triggers the immune system, which can go into overdrive when inflammation persists. Ongoing inflammation weakens the immune system and leaves the body more vulnerable to illness and disease.
The lining of the intestinal tract (small and large intestines) was designed to be semipermeable so it can allow important nutrients into the bloodstream, while keeping toxic materials out. Millions of cells linked together by proteins—known as tight junctions—fortify the intestinal wall to maintain this semipermeable state.
Zonulin, a protein discovered by Dr. Alessio Fasano, helps modulate the permeability of the tight junctions. Dr. Fasano’s research also suggests that gluten and bacteria in the small intestine are the two primary culprits that trigger zonulin levels to rise, which can be problematic.
When zonulin levels increase the tight junctions come apart, creating gaps in the gut membrane. This condition—known as leaky gut syndrome—allows larger pieces of undigested food and other toxins to leak into the bloodstream instead of being filtered through the kidneys and eliminated in urine.
Once the gut leaks, the immune system produces antibodies that attack food particles and other microbes circulating through the bloodstream as foreign invaders. The antibodies, now viewing previously harmless food particles as a threat, may resurface and mount future attacks the next time that food is eaten, resulting in a food allergy.