In his landmark 2009 study, Alessio Fasano, MD, suggested that three things must be present for an autoimmune condition to develop: a genetic predisposition, a trigger, and a leaky gut.
To understand leaky gut, let’s first look at how our bodies absorb nutrients. Your digestive tract is where food is broken down and nutrients are absorbed. Your intestines form part of your digestive tract. The wall of your intestines has a dual purpose.
It protects your body from harmful substances by controlling what enters the bloodstream and what is transported to your organs. It therefore acts as a protective barrier between your gut and your bloodstream. It also assists your body in absorbing nutrients. Your intestine wall has tiny finger like projections called villi. The villi fingers are covered with hairs called microvilli. The role of the villi is to grab micronutrients floating in your gut that have been broken down from the food you eat. The villi and the microvilli push these micronutrients directly into your bloodstream through tiny openings in your intestine wall, called tight junctions. Your blood then carries the micronutrients to all the cells in your body.
Intestinal permeability refers to how easily substances pass through the tight junctions of the intestinal wall. When the tight junctions stretch or break apart, the gut becomes more permeable (or leaky), which may allow undigested food, bacteria and toxins to pass from the gut into the bloodstream. This phenomenon is called leaky gut.
When the gut is leaky and the bacteria, toxins and other foreign invaders enter the bloodstream, our immune system recognizes them as foreign invaders and trigger an immune response against them. This could result in an autoimmune condition.