Free Digestive Wellness: Strengthen the Immune System and Prevent Disease Through Healthy Digestion, Fourth Edition by Elizabeth Lipski Page B

causes. The list of health conditions associated with increased intestinal permeability grows each year as we increase our knowledge of the synergy between digestion and the immune system. Currently there are more than 8,000 research articles on intestinal permeability.
    The small intestines have a paradoxical function. It allows only properly digested fats, proteins, and starches to pass through so they can be assimilated, while providing a barrier to keep out bacterial products, foreign substances, and large undigested molecules. This is called the barrier function of the gastrointestinal mucosal lining. This surface is often called the brush border because under a microscope its villi and microvilli look like bristles on a brush.
    In between cells are junctions called desmosomes. Normally, desmosomes form tight junctions and do not permit large molecules to pass through. When the area is irritated and inflamed, however, these junctions loosen up, allowing larger molecules to pass through. The substances that pass through the intracellular junctions are seen by our immune system as foreign, stimulating an antibody reaction. Whenthe intestinal lining is damaged, larger substances of particle size are allowed to pass directly, again triggering an antibody reaction. (See Figure 4.1 .)

     

    Figure 4.1 Leaky gut syndrome. (Used with permission from Genova Diagnostic Laboratory.)
     
    When the intestinal lining is damaged even more, substances larger than particle size—disease-causing bacteria, fungi, potentially toxic molecules, and undigested food particles—are allowed to pass directly through the weakened cell membranes. They go directly into the bloodstream, activating antibodies and alarm substances called cytokines. The cytokines alert our lymphocytes (white blood cells) to battle the particles. Oxidants are produced in the battle, causing irritation and inflammation far from the digestive system. Inflammation on this brush border can prevent small nutrients and food molecules from passing into the gut lumen. This is the primary cause of malabsorption.
    Intestinal mucus normally blocks bacteria from moving to other parts of the body. But when the cells are leaking, bacteria can pass into the bloodstream and travel throughout the body. When intestinal bacteria colonize in other parts of the body, we call it bacterial translocation, and it is often found in people with leaky gut syndrome. For example, Blastocystis hominis, a bacteria that causes GI problems, has been found in the synovial fluid in the knee of an arthritis patient. Surgery or tube feeding in hospitals can also cause bacterial translocation.
    Here’s how leaky gut syndrome works. Imagine that your cells need a kernel of corn. They are screaming out, “Hey, send me a kernel of corn.” The bloodstream replies, “I have a can of corn, but I don’t have a can opener.” So the can goes around and around while the cells starve for corn. Finally, our immune system reacts by making antibodies against the can of corn, treating the corn as if it were a foreign invader. Your immune system has mobilized to finish the job of incomplete digestion, but this puts unneeded stress on it. The next time you eat corn, your body already has antibodies to react against it, which triggers the immune system, and so on. As time goes on, people with leaky gut syndrome tend to become more and more sensitive to a wider variety of foods and environmental contaminants.
    Depending on our own susceptibilities, we may develop a wide variety of signs, symptoms, and health problems. Leaky gut syndrome is associated with the following medical problems: allergies, celiac disease, Crohn’s disease, HIV, and mal-absorption syndromes. It is also linked to autoimmune diseases such as AIDS, ankylosing spondylitis, asthma, atopy, bronchitis, eczema, food and environmental sensitivities, other allergic disorders, psoriasis, Reiter’s syndrome, rheumatoid arthritis, Sjögren’s syndrome, and