The term “leaky gut” has been a buzzword in the fitness industry, but what does it mean?
Well, it means pretty much how it sounds; your gut leaks. Technically known as intestinal permeability, leaky gut occurs when the intestinal lining becomes damaged, allowing undigested food particles, toxins, and bacteria to pass through the intestinal wall into the bloodstream.
This can lead to a host of health issues, such as digestive issues, fatigue, skin rashes, joint pain, and even mental health issues. The problem is that even though “leaky gut” is often talked about, it’s not medically or scientifically agreed upon.
Key Points You Need To Know!
“Leaky Gut” refers to increased permeability in your gut’s lining, allowing compounds to pass through.
Leaky gut has been sensationalized on social media, but it’s still a concern that can decrease health.
Improving gut permeability essentially means improving your gut’s overall health, which is definitely a plus.
Improving gut health requires systematic corrections, including increasing fiber, improving diet, following an active lifestyle, and supplementing where appropriate.
What Is Leaky Gut?
Leaky gut refers to permeability in the gut lining that allows compounds to seep through
Permeability likely occurs on some level all the time; Leaky gut refers to an increase.
Leaky gut occurs through paracellular (between cells) and transcellular (through cells)
Leaky gut is the buzzword used in fitness circles referring to something known as “Intestinal Permeability”.
Largely driven by chronic, systemic inflammation, intestinal permeability occurs when the gut lining is damaged, allowing for compounds to “leak” through (Camilleri, 2019).
When these compounds leak into the bloodstream, they cause disruption in various other physiological processes.
It’s important to understand that researchers believe intestinal permeability always occurs on some level. Therefore, leaky gut refers to an increase in this leakage.
Further, “leaky gut” is not a medical term and is debated by some within the medical community. These debates largely center around labeling it as a specific condition or as a secondary symptom (Lacy et al., 2024).
How Does Leaky Gut Occur?
While it may sound as if leaky gut occurs when the lining rips open, this isn’t true. In fact, there is no single route for leaky gut to occur, but there are two main pathways (Aleman et al., 2023).
1. Paracellular Route (Between Cells)
This pathway runs between intestinal epithelial cells and is most commonly associated with “leaky gut.”
It’s controlled by tight junction proteins, which act like gatekeepers. Under normal conditions, this route allows controlled movement of:
Water
Electrolytes
Small hydrophilic molecules
However, when they weaken, the spaces between cells widen, allowing larger or unwanted substances to pass through.
2. Transcellular Route (Through Cells)
This pathway moves substances through the epithelial cells themselves. This occurs through various processes such as endocytosis and vesicle transport.
Normally, it transports compounds through mechanisms such as;
Sugars
Amino acids
Vitamins
However, increased transcellular permeability sometimes allows larger and unwanted particles to cross this way. This allows microbial products to enter circulation, contributing to systemic inflammation.
What Causes Leaky Gut And Intestinal Permeability?
Key Points You Need To Know!
The primary driver of leaky gut is chronic inflammation
Causes of this inflammation include both lifestyle and diet choices
Low intake of fiber disrupts gut flora and is one of the foundational causes
Other common causes include a sedentary lifestyle, chronic stress, poor sleep, and certain drugs (NSAIDs).
The overarching cause of leaky gut is chronic and systemic inflammation. Therefore, what we’re really looking for is what causes this inflammation.
While there is no single cause, here are the most commonly associated behaviors and causes.
1. Dysbiosis and Gut Imbalance: Dysbiosis refers to an imbalance of “good” and “bad” bacteria in the gut. These imbalances are one of the primary causes of damaging inflammation of the gut.
2. Poor Diet: High consumption of processed foods, refined sugars, unhealthy fats, and gluten can trigger inflammation and weaken the intestinal barrier.
3. Chronic Stress: High levels of cortisol can weaken the immune system and impair gut function.
4. Certain Lifestyle Behaviors & Environment: Excessive alcohol, smoking, and exposure to environmental toxins or infections cause damage to the cells in the gut lining.
5. Poor Sleep Quality: Inadequate and disrupted sleep is a major cause of stress and increased cortisol.
6. Underlying Health Conditions: Conditions like Inflammatory Bowel Disease (IBD), celiac disease, and nutrient deficiencies (e.g., Vitamin D) directly affect intestinal integrity.
What Are Symptoms Of Leaky Gut?
Key Points You Need To Know!
There is no specific symptom of leaky gut
Many symptoms overlap with other issues, such as IBS and hormonal imbalances
Symptoms alone won’t indicate the presence of leaky gut
Checking your diet and lifestyle is a good indicator.
It’s crucial to understand that there are no specific symptoms that define leaky gut.
More importantly, you shouldn’t wait for symptoms before you take care of your gut. A healthy biome is crucial for optimal health, whether or not you necessarily notice poor symptoms.
However, if you notice the symptoms below and have no other explanation, assess your diet and lifestyle. If you know you’re not making the best health decisions, there’s a good chance your gut permeability is increasing.
1. Brain Fog- Systemic inflammatory signaling can affect neurotransmitter balance and blood–brain barrier function.
2. Bloating and Gas- Increased permeability can alter microbial balance and fermentation patterns, leading to excess gas production and abdominal distension.
3. Diarrhea or Loose Stools– Impaired tight junction integrity can disrupt fluid regulation in the intestines, reducing proper absorption.
4. Abdominal Pain or Discomfort– Low-grade inflammation in the intestinal lining can sensitize enteric nerves, increasing visceral pain perception.
5. Fatigue – Circulating endotoxins (e.g., LPS) can increase systemic inflammation, which is associated with reduced energy and increased cytokine activity.
6. Joint Pain – Elevated inflammatory mediators can contribute to systemic inflammatory symptoms, including joint discomfort.
7. Skin Issues (eczema, acne, rashes) – Immune activation and inflammatory signaling may manifest through dermatologic responses.
8. Insulin Resistance or Unexpected Weight – Endotoxemia is associated with impaired metabolic signaling, reduced insulin sensitivity, and even poor body composition.
How Can You Treat Leaky Gut?
Key Points You Need To Know!
Treating leaky gut requires a systematic strategy and starting at the foundational level.
Increasing activity, fiber intake, and diverse plant foods is the most practical first step.
The most promising supplements to improve gut health are probiotics and prebiotics.
Other vitamins and compounds have also been found to be effective: L-Glutamine, Vitamin A & D, and Colostrum.
If you are experiencing leaky gut or increased intestinal permeability, it’s important to realize it’s not treated in isolation.
Unlike a virus, intestinal permeability is usually the result of multiple systems being stressed and requires foundational help. This can include;
Restoring microbial balance and improving overall gut health
Reducing inflammatory stress to stop the breakdown
Providing the intestinal lining with the nutrients it uses to repair itself.
While there is no one food, here are some with the most promise and evidence to back up their use (Aleman et al., 2023).
Prebiotics And Fermentable Fiber
Prebiotics are certain types of fermentable fiber that produce Short-chain fatty acids (SCFAs), particularly butyrate. These SFCA are the primary fuel source for good bacteria in the gut and improve overall gut health (Mohr et al., 2020).
On the other hand, when fiber intake is low, SCFA production drops, and barrier integrity can weaken.
Increasing fermentable fibers may improve tight junction expression and mucus layer integrity.
Resistant starch
Inulin
Beta-glucans
Pectin
Acacia fiber
This fixes your gut at the foundational level and improves the gut flora balance, specifically increasing good bacteria. (Bhatia et al., 2025).
Probiotics: Decreases Permeability And Optimizes Flora
Probiotic strains are live bacteria that introduce “good” bacteria to the gut.
Their effects appear to come from improving the health of the gut by improving the flora and increasing short-chain fatty acid production (Jäger et al., 2016; Jäger et al., 2019).
They have been shown to offer numerous benefits to improving the gut, such as;
Strengthen tight junction protein
Increase mucus production,
Reduce inflammatory cytokines
SET FOR SET has begun offering an awesome probiotic supplement that combines prebiotics to optimize their efficiency. This is known as a synbiotic strategy and is likely the superior method of supporting gut health.
Vitamins A and D: Repair The Gut’s Lining
Both vitamins A and D have been found to play important roles in the integrity of the gut lining’s cells and immune balance (Cantorna et al., 2019)
They improve gut health by decreasing permeability through improving tight junctions and mitigating inflammation. On the other hand, deficits of vitamin A and D are associated with impaired barrier strength.
L- Glutamine: Fuels The Cells Of The Gut’s Lining
Glutamine is a primary fuel source for the intestinal lining’s cells. It has shown to improve tight junctions to “seal” the gut and protein expression to reduce inflammatory signaling (Perna et al., 2019).
Glutamine is one of the most commonly used clinical nutrients for barrier support and gut health (Perna et al., 2019).
Check out our own L-Glutamine supplement to add to your diet to support gut health and muscle recovery.
Increase Physical Activity And Exercise Promote A Healthy Gut
Beyond diet and supplementation, physical activity plays a foundational role in gut health and wellness.
While exercise is not a direct “treatment”, when compared to sedentary populations, physically active individuals consistently demonstrate;
Greater microbial diversity
Improved metabolic signaling
More resilient gut ecosystems
Decrease inflammation
All of these are crucial for a strong gut and lay the foundation for improving conditions (Jäger et al., 2019).
Research is clear that following a program leads to better results and increased adherence.
SET FOR SET has a host of training programs that will get the job done. For more serious, in-depth help, contact us for a personalized approach to reach your goals.
Final Say On Leaky Gut
Leaky gut has become a bit sensationalized online in the “functional fitness” circles, but it’s still a very real issue. More importantly, fixing leaky gut essentially means improving its health, which is definitely a crucial need that will provide a host of other benefits.
The bottom line is that a leaky gut is yet another symptom of lifestyles with low physical activity, poor diets, and certain lifestyle choices.
Follow a proper resistance training program, improve your diet, supplement with effective compounds, and fix your gut; your body will thank you.
FAQ: What Is Leaky Gut? Causes, Symptoms, And How To Fix It
1. What Is Leaky Gut?
“Leaky gut” refers to increased intestinal permeability, a condition where the gut lining is disrupted and allows larger particles, toxins, or bacterial components to pass into circulation. It is a measurable physiological phenomenon, but not a formal, standalone medical diagnosis.
2. What Causes Leaky Gut?
The primary driver of increased intestinal permeability is chronic inflammation. Common contributing factors include poor diet (low fiber, high processed foods), alcohol overuse, chronic stress, infections, obesity, metabolic dysfunction, and certain medications like NSAIDs.
3. What Are The Symptoms Of Leaky Gut?
Symptoms can include bloating, gas, diarrhea, food sensitivities, fatigue, brain fog, joint discomfort, and systemic inflammation. However, many of these symptoms are nonspecific and overlap with other gastrointestinal or inflammatory conditions.
4. How Do You Fix Leaky Gut?
Improving intestinal barrier function requires systematic intervention. It ultimately involves reducing inflammation, increasing fiber intake, and improving metabolic health. This can be done with resistance training, increasing diverse plant intake, use of targeted probiotics, adequate vitamin A&D, prioritizing sleep, limiting alcohol, and ultra-processed foods.
5. Is Leaky Gut Real Or Overhyped?
Increased intestinal permeability is real and documented in several disease states. However, the term “leaky gut syndrome” is often overused in popular media. While permeability can contribute to inflammation, it is usually a secondary effect rather than the sole root cause of chronic disease.
References
Aleman, R. S., Moncada, M., & Aryana, K. J. (2023). Leaky Gut and the Ingredients That Help Treat It: A Review. Molecules (Basel, Switzerland), 28(2), 619. https://doi.org/10.3390/molecules28020619
Bhatia, A., Sharma, D., Mehta, J., Kumarasamy, V., Begum, M. Y., Siddiqua, A., Sekar, M., Subramaniyan, V., Wong, L. S., & Mat Rani, N. N. I. (2025). Probiotics and Synbiotics: Applications, Benefits, and Mechanisms for the Improvement of Human and Ecological Health. Journal of multidisciplinary healthcare, 18, 1493–1510. https://doi.org/10.2147/JMDH.S501056
Camilleri M. (2019). Leaky gut: mechanisms, measurement and clinical implications in humans. Gut, 68(8), 1516–1526. https://doi.org/10.1136/gutjnl-2019-318427
Cantorna, M. T., Snyder, L., & Arora, J. (2019). Vitamin A and vitamin D regulate the microbial complexity, barrier function, and the mucosal immune responses to ensure intestinal homeostasis. Critical reviews in biochemistry and molecular biology, 54(2), 184–192. https://doi.org/10.1080/10409238.2019.1611734
Gurry T. (2017). Synbiotic approaches to human health and well-being. Microbial biotechnology, 10(5), 1070–1073. https://doi.org/10.1111/1751-7915.12789
Jäger, R., Mohr, A. E., Carpenter, K. C., Kerksick, C. M., Purpura, M., Moussa, A., Townsend, J. R., Lamprecht, M., West, N. P., Black, K., Gleeson, M., Pyne, D. B., Wells, S. D., Arent, S. M., Smith-Ryan, A. E., Kreider, R. B., Campbell, B. I., Bannock, L., Scheiman, J., Wissent, C. J., … Antonio, J. (2019). International Society of Sports Nutrition Position Stand: Probiotics. Journal of the International Society of Sports Nutrition, 16(1), 62. https://doi.org/10.1186/s12970-019-0329-0
Jäger, R., Purpura, M., Farmer, S., Cash, H. A., & Keller, D. (2016). Probiotic Bacillus coagulans GBI-30, 6086 reduces exercise-induced muscle damage and increases recovery. PeerJ, 4, e2276. https://doi.org/10.7717/peerj.2276
Lacy, B. E., Wise, J. L., & Cangemi, D. J. (2024). Leaky Gut Syndrome: Myths and Management. Gastroenterology & hepatology, 20(5), 264–272. https://pmc.ncbi.nlm.nih.gov/articles/PMC11345991/
Perna, S., Alalwan, T. A., Alaali, Z., Alnashaba, T., Gasparri, C., Infantino, V., Hammad, L., Riva, A., Petrangolini, G., Allegrini, P., & Rondanelli, M. (2019). The Role of Glutamine in the Complex Interaction between Gut Microbiota and Health: A Narrative Review. International Journal of Molecular Sciences, 20(20), 5232. https://doi.org/10.3390/ijms20205232
Mohr, A. E., Jäger, R., Carpenter, K. C., Kerksick, C. M., Purpura, M., Townsend, J. R., West, N. P., Black, K., Gleeson, M., Pyne, D. B., Wells, S. D., Arent, S. M., Kreider, R. B., Campbell, B. I., Bannock, L., Scheiman, J., Wissent, C. J., Pane, M., Kalman, D. S., Pugh, J. N., … Antonio, J. (2020). The athletic gut microbiota. Journal of the International Society of Sports Nutrition, 17(1), 24. https://doi.org/10.1186/s12970-020-00353-w
