What is leaky gut?

Think of your digestive system as a sort of self-contained plumbing system: food goes in the mouth, to the stomach to be partially digested, and on to the intestines, where food is further digested and nutrients are extracted, and then on to the colon where indigestible material is eliminated. Critical to the health of this system is a layer of tightly packed cells called epithelial cells which line the inside of the stomach and intestines, creating a protective barrier. The spaces in between these epithelial cells (called “tight junctions”) are normally sealed, but when the intestinal barrier becomes inflamed, damaged, and/or irritated, gaps can develop between the cells, allowing unwanted molecules from the intestines to pass through into the body. When the intestinal barrier becomes further damaged, larger substances like bacteria, undigested food particles, and toxins can pass directly through the damaged intestinal wall. The body recognizes them as foreign and mounts an immune response against itself, potentially leading to the development of food allergies and autoimmune diseases like multiple sclerosis, inflammatory bowel diseases like Crohn’s disease and ulcerative colitis, and lupus. It also causes systemic inflammation throughout the body.^{5 6}

Before the development of serious autoimmune disease, other symptoms can arise from a damaged intestinal barrier. While some of them are digestive-related (bloating, diarrhea, gas), many are not, making a diagnosis of leaky gut challenging. These symptoms may include seasonal allergies, hormonal imbalances, psoriasis, joint pain, chronic fatigue, food allergies, a weakened immune system, and mental health issues such as depression and anxiety.⁷

Support, heal, and maintain your gut barrier

The most obvious way to keep your gut barrier healthy is to cut out, or at least reduce, the lifestyle factors that may be causing harm. Cut out the junk food and focus on eating a whole-foods diet full of fiber-rich organic produce—this goes a long way to keep the gut in tip-top shape. Reducing or stopping alcohol consumption and cutting back on sugary foods will help speed the healing process. Make it a habit to include plenty of fermented foods and gut-healing bone broth in your diet, as well as healthy fats from coconut oil, coconut milk, and grassfed butter (if you can tolerate dairy).

Eating a healthy diet will support overall digestive health, laying the foundation for a healthy gut. For more targeted support in healing and maintaining the integrity of your gut barrier, consider these supplements.

Pre- and probiotics.

Prebiotics and probiotics improve the gut’s environment by promoting a healthy balance of bacteria. By cultivating overall health in the gut, they can reduce the permeability of the gut lining. Prebiotics act as “food” for the good bacteria in the gut and is found in many fiber-rich foods (think fresh vegetables); common supplemental sources include FOS (fructooligosaccharide), inulin, psyllium, and ground flax seeds. Probiotics introduce healthy bacteria to the gut and can reduce gut barrier dysfunction caused by dysbiosis. Look for a multi-strain probiotic supplement that contains both Lactobacillus and Bifidobacterium species.^{8 9}

Glutamine.

The amino acid glutamine is the primary fuel source for the cells in the intestinal lining and enhances the growth of intestinal endothelial cells. It plays an important role in maintaining the health of the intestinal barrier and regulating the function of the tight junctions between intestinal cells. Research has found that in the absence of glutamine, there is “significant breakdown in barrier function.”^{10 11}

Quercetin.

The flavonoid quercetin is known for its powerful anti-inflammatory and antioxidant effects, and research shows that it also enhances intestinal tight junction function, but through a different mechanism—it appears that quercetin interacts with signaling molecules (molecules that communicate with cells, giving them “instructions”) that regulate the normal functioning of intestinal tight junctions. Other research has found that quercetin alone or combined with resveratrol (another plant-derived antioxidant) modulate the gut bacteria, helping to correct dysbiosis.^{12 13 14}

Even with so many common lifestyle factors that can damage our guts, the epithelial cells that make up the gut barrier are replaced every four to five days, providing us with ample opportunities to support its best health. As we continue on our quest to get healthy, let’s make gut health a priority, because a healthy gut = a healthy you!

References

1. Stonehill M, “Much still to discover on role of gut microbiome in immune system.” Healio Gastroenterology, Dec 2021. https://www.healio.com/news/gastroenterology/20211213/much-still-to-dis…
2. Paray BA, Albeshr MF, Jan AT, and Rather IA. “Leaky Gut and Autoimmunity: An Intricate Balance in Individuals Health and the Diseased State.” Int J Mol Sci. 2020 Dec; 21(24): 9770 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7767453/
3. Liu J, Zhao F, Xu Y, Qiu J, Qian Y. Gut Flora-Mediated Metabolic Health, the Risk Produced by Dietary Exposure to Acetamiprid and Tebuconazole. Foods. 2021 Apr 12;10(4):835. doi:10.3390/foods10040835
4. Kinashi Y and Hase K. “Partners in Leaky Gut Syndrome: Intestinal Dysbiosis and Autoimmunity.” Front. Immunol. 22 April 2021 https://doi.org/10.3389/fimmu.2021.673708
5. Kong S, Zhang YH, and Zhang W. “Regulation of Intestinal Epithelial Cells Properties and Functions by Amino Acids.” Biomed Res Int, May 9, 2018. doi: 10.1155/2018/2819154
6. Paray BA, Albeshr MF, Jan AT, and Rather IA. “Leaky Gut and Autoimmunity: An Intricate Balance in Individuals Health and the Diseased State.” Int J Mol Sci. 2020 Dec; 21(24): 9770 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7767453/
7. “Endogrinology: 11 Signs of Leaky Gut Syndrome,” 01 Nov 2019. Medanta Wellness Blog Leaky Gut Syndrome_ Causes, Symptoms, Foods to Eat & Foods to Avoid _ Medanta.html
8. Paray BA, Albeshr MF, Jan AT, and Rather IA. “Leaky Gut and Autoimmunity: An Intricate Balance in Individuals Health and the Diseased State.” Int J Mol Sci. 2020 Dec; 21(24): 9770 https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7767453/
9. Kinashi Y and Hase K. “Partners in Leaky Gut Syndrome: Intestinal Dysbiosis and Autoimmunity.” Front. Immunol. 22 April 2021 https://doi.org/10.3389/fimmu.2021.673708
10. Li N, Lewis P, Samuelson D, Liboni K, and Neu J. “Glutamine regulates Caco-2 cell tight junction proteins.” American Journal of Physiology Gastrointestinal and Liver Physiology, 01 Sep 2004. https://doi.org/10.1152/ajpgi.00012.2004
11. Kong S, Zhang YH, Zhang W. Regulation of Intestinal Epithelial Cells Properties and Functions by Amino Acids. Biomed Res Int. 2018 May 9. doi: 10.1155/2018/2819154
12. Suzuki T and Hara H. “Role of flavonoids in intestinal tight junction regulation.” The Journal of Nutritional Biochemistry. May 2011; vol 22(5): 401-408. https://doi.org/10.1016/j.jnutbio.2010.08.001
13. Zhao L, Zhang Q, Ma W, Tian F, Shen H, Zhou M. A combination of quercetin and resveratrol reduces obesity in high-fat diet-fed rats by modulation of gut microbiota. Food Funct. 2017 Dec 13;8(12):4644-4656. doi: 10.1039/c7fo01383c
14. Lin R, Piao M, Song Y. Dietary Quercetin Increases Colonic Microbial Diversity and Attenuates Colitis Severity in Citrobacter rodentium-Infected Mice. Front Microbiol. 2019 May 16;10:1092. doi: 10.3389/fmicb.2019.01092