While it is not yet a widely recognized medical condition, integrative and functional medicine doctors are at the forefront of diagnosis and treatment, while more research is starting to emerge to explain what it is and how to heal it. In a healthy gut, when you digest food, your intestines break it down, allowing tiny healthy nutrients to pass through the walls into the bloodstream. But, “when the permeability of the gut lining has been altered, this allows toxins, bacteria, and foreign substances like undigested food particles to enter the blood stream along with the nutrients,” explains family medicine physician Bindiya Gandhi, M.D.. “The connections between the cells that line the inside of the intestines (known as tight junctions) become looser,” adds gut health expert Vincent Pedre, M.D.. Some practitioners believe that addressing leaky gut can help heal underlying conditions before they get worse, but this has yet to be medically proven1. What is evident, though, is that the gut is closely connected to overall health. Long-term use of some anti-inflammatory medications like ibuprofen and aspirin4 may also affect the gut. “When the gut is unhealthy the intestinal lining can become worn and ‘broken,’ literally forming cracks or holes at the cellular level,” explains naturalistic nurse Audrey Christie, MSN, RN, CCMA. According to a 2020 study by the University of California San Diego School of Medicine, leaky gut is most often experienced by people who are older, have chronic conditions, or high-stress lifestyles. The same study also found evidence of what may be the root cause of leaky gut—a molecular mechanism called the stress-polarity signaling pathway, which helps keep the gut lining functioning properly. When this mechanism comes under stress, it can create chronic inflammation in the digestive tract, which can be a trigger for more gut damage and other issues. And because the immune system is on high alert, it can result in body-wide inflammation. This manifests in a variety of physical symptoms, from digestive issues to skin irritation. As Pedre explains it, “Leaky gut is not a diagnosis but a process, a description of the underlying pathology of numerous diseases that we treat yet have failed to find a cure for.” However, there are some signs and symptoms you can look out for that may indicate a more permeable gut lining. A 2015 study in the Intestinal Research journal found a direct correlation between intestinal barrier damage and the progression of irritable bowel disease5 (IBD). So when it’s not working properly, your natural hormone balance can be disrupted6, contributing to conditions like endometriosis and PCOS. These disorders are caused by a combination of genetic and biological factors, and according to multiple recent studies7, intestinal barrier dysfunction may also play a role in triggering them. Pedre explains, “Your immune system is constantly patrolling the gut border for anything it does not recognize in order to prevent an all-out invasion.” But, when an individual has a “leaky gut” the immune system finds and attacks all of the escaped particles. Paired with a genetic predisposition to autoimmune diseases, “this increased load on the immune system leads to the type of dysregulation that becomes an autoimmune disease,” he adds. Chronic fatigue syndrome and fibromyalgia have both been linked to an altered gut microbiome composition, likely as a result of damaged intestinal barriers. Acne, rosacea, and eczema8 can all be exacerbated by inflammation in the digestive tract. A 2014 study in the FEBS Letters journal found that rheumatoid arthritis (when your joints are persistently swollen and painful) is linked to dysbiosis in the gut microbiome11. To combat your gut issues naturally, Christie recommends some lifestyle changes. “I start people with sleep and stress,” she says. “When you are getting good quality and quantity of sleep, and your stress is mitigated, not only are you actively healing your body, [but] you are also setting the stage for more challenging lifestyle behavior modification.” Once you’ve lowered your baseline of stress, you can work on rebuilding the good gut bacteria to support damaged tissue repairs. Christie advises clients to eat a wide variety of plant foods in their diet. “Shifting the food you are consuming away from processed and damaging foods to more organic, whole, plant foods is always beneficial,” she says. She typically suggests cutting out gluten, dairy, and eggs to begin the healing process, and instead opting for fresh fruits and vegetables. Supplements are also a key lifestyle change. Taking a daily probiotic will introduce good bacteria back into your digestive system and support the healing process.* There’s the obvious connection to digestive issues, and then the more surprising links to skin irritation, fatigue, and chronic conditions. If you are experiencing these symptoms, consider talking to your health care provider and tweaking your lifestyle to start rebuilding your gut microbiome and intestinal walls. With the right combination of a healthy diet, supplements, and adequate rest, you can work on healing from the inside out.* Editor’s Note: This article was originally published on September 12, 2013. A previous version of this article misstated the publication date of a study. We have since corrected this article to indicate that the study was published in 2020.