Gut leak – your hungry microbes need to be fed, or they’ll dine on their host!

Perhaps most of us have heard of the term “leaky gut,” but what is it and how can we avoid it? If you try to picture a leaky gut in your mind maybe it comes as swelling and inflammatory fluids pouring by. But you could get a better picture if you replace that inflammatory fluid with bacteria. A leaky gut is one that has a severe problem in the intestinal barrier, the one that keeps the intestinal bacteria off the bloodstream. However, even if bacteria don’t go that far, they can take over areas in your intestines where they shouldn’t be; for example, invading your epithelial lining through the mucosa layer.


Intestinal barrier and the leaky gut
From the inside of your mouth, down the lower esophageal sphincter, through the stomach and intestines, to the anus, the human gastrointestinal tract has a single continuous coating of mucosal cells that separates the inside of the body from the external environment. This lining of cells is heavily involved in the secretion of organic by-products such as immunoglobulin, mucous, defense peptides, and other antimicrobial agents.


This barrier is not only significant to keep bacteria from coming in contact with your blood. The gastrointestinal mucosal barrier also protects your gut from toxins and allergens that could cause inflammation and immunological stress. You may not end up with bacteria in your blood, but this misplacing of allergens and toxins can generate a series of symptoms and diseases. After a leaky gut, you can experience recurrent episodes of diarrhea and constipation, suffer from nutritional deficiencies, celiac disease, and inflammatory bowel diseases like Crohn’s disease and ulcerative colitis.


There are plenty of reasons why the gut mucosal barrier can be compromised. Most of them have to do with aggressive therapy such as chemotherapy and radiation therapy. Severe infections, immunosuppression –such as in HIV- and trauma can cause a leaky gut as well. But even mild conditions such as parenteral feeding and even emotional stress could trigger this problem.


Probiotics and leaky gut
Scientific research has reported that probiotics supplements can significantly protect the gut and promote intestinal barrier integrity. Different strains and probiotic groups can have different protective effects towards the mucosal barrier. Almost all of them reduce inflammation and improve the function of tight junctions. As for the latter, they are particular structures located between two cells to assemble them tightly and avoid diffusion across the epithelium. In other words, they function as sealing agents closing the gaps between one cell and the other.


According to different studies, each strain has unique properties. Probiotics with Lactobacillus species normalize the distribution of the proteins that make up tight junctions, and by putting the pieces back in place, these probiotics make the intestinal barrier go back to normal. Another useful species is Bifidobacteria, especially if we want to treat and prevent colitis because they prevent these tight junction proteins to go astray. A third strain is Saccharomyces, which promotes the formation of these sealing structures. As shown by many studies, using probiotics to prevent and treat a leaky gut is based on solid science and many applications are still under research.


REFERENCES:
Hollander, Daniel. "Intestinal permeability, leaky gut, and intestinal disorders." Current gastroenterology reports 1.5 (1999): 410-416.
Fasano, Alessio. "Leaky gut and autoimmune diseases." Clinical reviews in allergy & immunology 42.1 (2012): 71-78.
Ukena, Sya N., et al. "Probiotic Escherichia coli Nissle 1917 inhibits leaky gut by enhancing mucosal integrity." PloS one 2.12 (2007): e1308.
Michielan, Andrea, and Renata D’Incà. "Intestinal permeability in inflammatory bowel disease: pathogenesis, clinical evaluation, and therapy of leaky gut." Mediators of inflammation 2015 (2015).
Krishna Rao, R., & Samak, G. (2013). Protection and restitution of gut barrier by probiotics: nutritional and clinical implications. Current Nutrition & Food Science, 9(2), 99-107.
Hardy, H., Harris, J., Lyon, E., Beal, J., & Foey, A. D. (2013). Probiotics, prebiotics and immunomodulation of gut mucosal defences: homeostasis and immunopathology. Nutrients, 5(6), 1869-1912.