If your small and large intestines are healthy, they're semi-permeable. That means they allow important ions and nutrients to pass through the intestinal walls and into your bloodstream. That's good. The mucosal walls of your intestines are made of epithelial cells that have "tight junctions" between them, to keep undigested food, pathogens and toxins from slipping through and entering the bloodstream on the other side of the gut wall.
Leaky gut is when your gut walls become too permeable. This can be caused by the effects of pathogenic bacteria, viruses, parasites, fungi and toxins that can modulate the structure and function of these tight structures over time. Or by other stimuli from pharmacological (drugs) and physiological sources. Even things like stress, environmental toxins and a bad diet can make a huge difference. Keeping your gut healthy can help avoid leaky gut. And prevention is key.
When presented with pathogens, toxins and foreign bodies like undigested food particles, your system may produce antibodies that trigger inflammatory reactions throughout the body – in the blood vessels, joints, gut, brain or lungs.
Once leaky gut starts, it generally gets worse if not corrected. Toxins entering the circulatory system from the gut can go directly to the liver, and then on to the rest of the body. Along the way, they may create inflammation that can cause a host of complications and illnesses. On top of this, you now have to defend against diseases with a compromised immune system, since your gut is not working at its best.
And having prebiotic fibers in your daily diet can support your gut performing better, to help keep you healthier.