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Leaky gut

The GI tract's role

Perkins, Amanda DNP, RN

doi: 10.1097/01.NME.0000585104.17129.f6
Department: Patho Puzzler
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Amanda Perkins is an Associate Professor of Nursing at Vermont Tech in Randolph, Vt., and a Nursing made Incredibly Easy! Editorial Board Member.

The author has disclosed no financial relationships related to this article.

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Current research is revealing an important relationship between gastrointestinal (GI) health and overall health. In this article, we'll take a look at leaky gut—a disorder that can occur when intestinal permeability is increased—including the anatomy and physiology of the GI tract, gut microbiota, and ways to prevent or reverse leaky gut.

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What's leaky gut?

The term leaky gut is becoming increasingly popular in both community and healthcare settings. Although leaky gut is the common term, it's another way of saying increased intestinal permeability. To understand what leaky gut is, we first need to understand the normal anatomy and physiology of the GI tract.

The intestines have an epithelial lining that, when combined with secreted factors, forms a barrier to help control the movement of fluid and macromolecules. Under optimal conditions, the intestinal lining forms a tight barrier that prevents the passage of unwanted material from the GI tract into the blood and surrounding tissues. In the intestines, there's a single layer of specialized epithelial cells linked together by tight junction proteins. There are multiple types of functional intestinal epithelial cells in the GI tract, including enterocytes, goblet cells, and Paneth cells.

Accounting for at least 90% of the functional intestinal epithelial cells, enterocytes, a type of villus cell, are necessary for the uptake of nutrients, nutrient absorption, and digestion. Goblet cells are responsible for storing and secreting mucus that acts as both a lubricant and barrier to protect against the adherence of unwanted microorganisms. And Paneth cells play an important role in antibacterial defenses. Mucins, antimicrobial molecules, immunoglobulins, and cytokines also play a role in the development of leaky gut.

Any abnormality in the GI tract may increase intestinal permeability, leading to leaky gut. When a patient has leaky gut, his or her intestinal lining doesn't form a tight barrier, which allows partially digested food, toxins, and microorganisms to escape (see A closer look at leaky gut). The body mounts an immune response when this happens, creating antibodies meant to attack the foreign material. Leaky gut can cause both local and systemic immune responses, leading to sickness in the patient experiencing it.

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Gut microbiota: The bacterial component

Microorganisms in the GI tract appear to play an essential role in the prevention or development of leaky gut. Made up of bacteria and other classes of microbes, such as fungi and viruses, the gut microbiota is so significant that it's been referred to as the microbial organ. It's interesting to note that the gut microbiota components can communicate with one another, in addition to communicating with the host. The gut microbiota, or gut ecosystem, is broken down into sections in the GI tract, which include the mouth, esophagus, stomach, small intestine, and large intestine. Within each of these sections, the gut ecosystem will vary. However, it's been found that the gut ecosystem of the mouth and colon (large intestine) are similar.

Microorganisms in the GI tract promote resistance to the colonization of harmful microorganisms by using up nutrients, occupying attachment sites, and releasing antimicrobial substances. The gut microbiota also stimulates antibody production, which in turn increases cell-mediated immunity, effectively preventing the overgrowth of organisms that could be harmful to the host. Additionally, these microorganisms regulate digestion and absorption of nutrients for epithelial cells. Keep in mind that a variety of different factors can alter the diversity of the gut microbiota.

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Contributing factors

Although leaky gut can cause significant problems, it can be reversed relatively easily through a variety of lifestyle changes. Research has shown that diet can contribute to alterations in gut microbiota and intestinal barrier function. This can be positive or negative, with a healthy diet providing a protective function and an unhealthy diet contributing to the development of leaky gut. Individuals with different diets, such as those who primarily eat meat versus those who primarily eat vegetables, have a very different gut ecosystem. Evidence has shown that the standard American diet can lead to leaky gut because it's made up of foods low in fiber and high in sugar and saturated fats. Low-fiber diets and increased intake of saturated fats can lead to impaired intestinal barrier function and increased permeability.

Research has shown that obesity can also affect the gut microbiota. Individuals who are obese have a gut ecosystem that's less diverse than those with a healthy weight. Additionally, alcohol, stress, and gut microbiota dysbiosis (imbalance) can play a role in the development of leaky gut. The use of antibiotics is a common cause of gut microbiota dysbiosis. Nurses are very much aware of the Clostridium difficile infections that can occur with or after the administration of antibiotics. This is due to gut microbiota dysbiosis. When our patients have an active C. difficile infection, it's quite easy to detect. What isn't easy to detect or fully understand are the subtle changes that can occur to the gut microbiota after antibiotic administration. Currently, the effects of these changes and the length of time they'll affect the patient are unknown.

Certain conditions, such as ulcerative colitis and Crohn disease, lead to inflammation that increase the risk of leaky gut. Additionally, food sensitivities, such as celiac disease, may also predispose a person to the development of leaky gut. When caring for patients with conditions that can increase the likelihood of leaky gut, be aware of the heightened risk and ways of minimizing it.

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Probiotics and prebiotics

Research has shown that both prebiotics and probiotics can contribute to the prevention and reversal of leaky gut, posing little risk to the individual consuming them. Live microorganisms that are ingested for their positive benefits on the GI tract, probiotics are believed to enhance the production of tight junction proteins. Prebiotics, substances that aren't digested by humans, are used because they're fermented by the gut microbiota, aiding in its growth and activity. Basically, prebiotics feed the good bacteria in the gut, helping maintain a healthy gut ecosystem.

Although still ongoing, research has shown that probiotics can be used to prevent and potentially reverse certain diseases and disorders. Consuming dairy products, such as milk, yogurt, and cheese, is an easy way for patients to receive probiotics. Be aware of patients with sensitivities to dairy products and help them identify probiotic alternatives. Patients can also increase their intake of beneficial microorganisms by consuming fermented foods, such as milk kefir, water kefir, kombucha, and sauerkraut. Probiotics can be taken in the form of capsules and tablets as well.

As is the case with probiotics, prebiotics can be taken as a supplement or added to the body through simple dietary measures. Examples of foods rich in prebiotics are garlic, onions, bananas, oats, asparagus, beets, sweet potatoes, yams, and yucca.

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Final thoughts

Research has shown that there's a strong connection between the gut and the brain. As a result, any condition affecting the GI tract, such as leaky gut, can lead to an imbalance and illness within the body. It's essential for nurses to be able to recognize this connection and guide patients to a healthier way of life. Although more research on leaky gut is needed, it's important to understand that we can alter gut microbiota to enhance our patients' health and wellness. Nurses can play a role in the prevention of leaky gut by reviewing the most current research and recommending healthy lifestyle changes.

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A closer look at leaky gut

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Luminal and circulating toxins may disrupt the healthy mucosal barrier, impairing nutrition and promoting systemic entry of noxious inflammatory and immunoregulatory products.

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on the web

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Harvard Health:www.health.harvard,edu/blog/leaky-gut-what-it-is-and-what-does-it-mean-for-you-2017092212451

Johns Hopkins Medicine:www.hopkinsmedicine.org/health/wellness-and-prevention/the-brain-gut-connection

Mayo Clinic:www.mayoclinic.org/healthy-lifestyle/nutrition-and-healthy-eating/in-depth/for-healthy-gut-feed-good-bugs/art-20322495

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did you know?

The useful appendix

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Current research suggests that the appendix plays an important role in the health of our gut microbiota and the intestinal immune system. Research has shown that the appendix may act as an incubator and storage facility for microorganisms and has a direct functional interaction with the gut microbiota. Additionally, it's believed that the appendix can reintroduce needed strains of bacteria to the intestines on an as-needed basis.

Research on the link between disease and appendix removal is ongoing. It's been shown that there's a link between the removal of the appendix and certain diseases, such as cancer of the GI tract (specifically the large bowel). Although in its infancy, research has also shown a link between appendix removal and mood disturbances, such as depression and anxiety. At this time, more research about the appendix's role in GI health is needed.

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