What Causes Leaky Gut? 5 Root Triggers You Need to Know

“What causes leaky gut” is a question many people ask when faced with chronic bloating, fatigue, inflammation, and food sensitivities or intolerances. The term “leaky gut” is more formally known as increased intestinal permeability. Let’s dive deep into leaky gut together and discuss five root causes that could be sabotaging your gut health and leading to stubborn symptoms.

What You Need to Know About Leaky Gut

Thank you, Hippocrates, for the ancient wisdom that “all disease begins in the gut.” While there is still so much to be uncovered about the science of the gut microbiome, we know from modern research that gut health is at the core of overall health. It impacts brain function, mental health, stress resilience, hormone balance, thyroid function, and so much more.

Leaky gut, or increased intestinal permeability, happens when the tissue of the intestinal lining becomes compromised, weak, or permeable. In other words, it goes from being able to tightly control what’s coming into your body from your digestive tract, to having gaps where food particles, toxins, and microbes can now slip through the cracks and enter your bloodstream.

Signs of leaky gut can be surprisingly widespread, considering that when these components pass into your bloodstream (where they should not be), this sends inflammatory signals and triggers an immune response throughout the body. Symptoms related to leaky gut include:

• Bloating, gas, and digestive discomfort
• Food sensitivities or intolerances
• Fatigue and brain fog
• Skin issues like eczema, rosacea, and other rashes

Leaky gut is also linked to micronutrient deficiencies given impaired digestion and absorption, as well as autoimmune conditions like Hashimoto’s thyroiditis and hormonal conditions such as PCOS. Let’s explore five root triggers of leaky gut you need to know.

Root Trigger #1. Chronic Stress 

Short-term or acute stress is not the problem. However, when stress and cortisol levels are chronically elevated, this is when chronic health issues arise. Chronically elevated cortisol levels weaken the gut barrier and divert resources away from digestion. 

When your body is stuck in this “fight-or-flight” mode (sympathetic nervous system state), blood flow is shunted away from the digestive tract. This also causes a decrease in stomach acid, digestive enzyme output, and bile flow – all of which are critically important for nutrient absorption and microbiome balance.

Over time, this fuels leaky gut, intestinal inflammation, and an imbalanced gut microbiome. Managing stress is essential for gut healing. Mindfulness practices like breathwork, yoga, meditation, and even simply being present and chewing thoroughly during meals can be powerful gut-supportive strategies.

Root Trigger #2. Medications

Certain medications are well-documented gut disruptors. NSAIDs (non-steroidal anti-inflammatory drugs, such as ibuprofen, aspirin, and naproxen) have been shown to be toxic to the cells of the intestinal lining, both inducing and worsening intestinal permeability.

Antibiotics, while sometimes life-saving, don’t distinguish between the “good” and “bad” bacteria in the gut. Wiping out the beneficial bacteria impairs the integrity of gut lining, as these bacteria produce important anti-inflammatory and healing post-biotic compounds, such as short-chain fatty acids.

Finally, acid blockers, also known as proton-pump inhibitors (PPIs – like Prilosec and Nexium) or H2 blockers (like Zantac and Pepcid) can also impact gut health. These can be necessary when used short term and in the right circumstances, but chronically suppressing stomach acid impairs protein digestion in particular and alters gut pH (acid-base balance). In the long run this paves the way for bacterial overgrowth, gut dysbiosis, and leaky gut.

Root Trigger #3. Toxins & Environmental Exposures

In the current world we live in, exposure to pesticides, heavy metals, mold, microplastics, and other toxins is inevitable. Unfortunately, many of these toxins fuel oxidative stress and directly irritate or damage the gut lining. 

We talk a lot about the importance of liver function here at Functional Fueling, especially its role in detoxification and hormone health. One of the liver’s main responsibilities is to eliminate these toxins from the body, which can be a lot to ask for depending on someone’s long-term exposure and other aspects of their health. 

If you have high levels of these accumulated toxins, liver function is going to suffer along with other body systems. Signs of high toxic burden may include headaches, joint pain, muscle weakness, skin rashes, fatigue, or worsening gut symptoms. Using advanced functional testing to assess for mold mycotoxins, heavy metals, and chemical exposures, we can design a personalized detoxification support protocol to help address the root of your leaky gut.

Root Trigger #4. Latent Viral Infections

Latent viral infections stay dormant in the body after initial infection, and can reactivate under certain conditions and escalate into a more active infection. Examples of these types of infections include Epstein-Barr virus (EBV, which causes mononucleosis, aka “mono”), Cytomegalovirus (CMV), Herpes Simplex virus (HSV), or high post-COVID viral load. 

These are often overlooked gut and immune disruptors. While these viruses may not always cause symptoms, they keep the immune system on high alert, fueling chronic stress and inflammation, which we know is a leaky gut trigger. Problems arise when these viruses reactivate (when under stress, immune suppression, hormonal changes, other infections, etc.) or when viral load remains chronically elevated.

Functional medicine approaches focus on supporting the immune system, even modulating immune system responses using different treatment modalities, lowering chronic stressors, and rebuilding resilience to reduce the viral burden. All of this in turn also supports gut health, considering that 70-80% of our immune cells are housed within the gut.

Root Trigger #5. Nutrition and Dietary Factors

It’s often said by functional medicine practitioners that “food is information.” Certain foods are known to fuel inflammation and compromise the gut barrier, such as excess refined sugar, alcohol, ultraprocessed foods, and gluten in many individuals. 

Plenty of other foods that are rich in micronutrients and antioxidants help build a more resilient microbiome and more robust gut health. Unfortunately, nutritional gaps from a diet that lacks fiber diversity, polyphenols, phytonutrients, vitamins and minerals leaves the microbiome undernourished and the gut more vulnerable to intestinal permeability. 

Food sensitivities often arise in the case of leaky gut. This is because when food particles slip through the intestinal lining this triggers an immune response, causing the body to view certain foods as harmful. This leads many individuals with GI symptoms to cut out more and more foods, creating an increasingly limited diet.

Want Deeper Insight into YOUR Root Triggers?

Leaky gut isn’t just a buzzword, it’s a real, research-backed condition with ripple effects across so many body systems. To truly heal leaky gut, it’s important to investigate these five major triggers, which can compromise gut integrity and fuel systemic inflammation

The good news? With the right testing, nutrition, and lifestyle support, you can heal! In our 1:1 Coaching Program we address the root causes so that you don’t just improve digestion, you support your immune system, hormones, and overall vitality. Ready to start your healing journey? Book a free discovery call today!

Written by Romana Brennan, MS, RDN