The lining of our digestive tract is naturally semi-permeable, which means that it allows certain things, such as nutrients, water, and energy to pass through into the bloodstream. This membrane has tiny pores that enable these nutrients to pass through. However, excessive stress and inflammation can result in damage to this lining, causing the holes to enlarge and, in turn, enabling larger, undigested nutrients to leak into the bloodstream. Studies suggest that individuals with autoimmune, inflammatory, and gastrointestinal diseases are more likely to have a 'leaky gut' that allows these big particles through. The particles that leak through can include undigested foods, bacteria, viruses, and other pathogens that can invade the gut.