If you have a leaky gut – also called increased intestinal permeability – substances that should stay in the gastrointestinal (GI) tract pass through spaces called tight junctions. In a healthy gut, tight junctions act like gatekeepers, keeping partially digested food and microbiota in and allowing nutrients out as needed. But if physical damage, chemical damage, pathogens, or illness injures the GI tract, the tight junctions loosen, leading to a leaky gut. A leaky gut is a risk factor for developing other conditions, including Crohn’s Disease, autoimmune and neurological disorders, and allergies.
What Exactly Is the Gut?
The gut, or gastrointestinal system, includes everything from the mouth to the anus – with the esophagus, stomach, small and large intestine (colon) in between. The small intestine and large intestine contain roughly 2,700 square feet of surface area, which is about the size of a tennis court. Finger-like projections called villi line the intestinal wall and help with nutrient absorption.
A single layer of epithelial (skin) cells exists in the stomach and intestines where they secrete mucus into the area where the microbiota live to promote smooth digestion.
The gut is also an immune system organ. The mucosal membrane (epithelial cells, villi, tight junctions, mucous layer, and connective tissue or lamina propria) contains dome-like regions of lymphatic tissue called Peyer’s patches that coordinate immune responses.
What Is a Leaky Gut?
In a healthy gut, tight junctions in between epithelial cells act like gatekeepers that selectively let substances in and out. But, if the spaces between epithelial cells loosen, then toxins, food molecules, and pathogens can pass through. This can lead to inflammatory bowel disease or other conditions. Nature Immunology created a wonderful video that shows how the mucosa works and what can cause leaky gut.
Leaky Gut vs. Leaky Gut Syndrome
You may hear the phrase leaky gut syndrome, which natural health proponents use but some conventional medicine proponents criticize. Getting caught up in whether we use the term “syndrome” or not is an unnecessary distraction. Some aspects of leaky gut are still under investigation, but there is already a strong scientific consensus that:
- Several health conditions co-occur with leaky gut.
- Leaky gut can cause – not just result from – certain diseases and conditions.
- Specific factors cause tight junctions to malfunction, leading to a leaky gut.
Thirty years ago, the scientific community resisted Dr. Daniel Hollander’s idea that a leaky gut could cause inflammatory bowel disease (IBD) – as opposed to being caused by the disease. Today, however, gastroenterologists widely accept the knowledge that leaky gut can lead to specific symptoms and conditions, ranging from mild to severe.
Symptoms of Leaky Gut
Because a leaky gut allows foreign bodies to enter the bloodstream, it exerts a wide range of effects on the body that go beyond digestion. Some of the issues and symptoms known to co-occur with leaky gut include:
- Food allergies and asthma[6, 7]
- Cardiovascular issues
- Metabolic disruptions
- Depression, anxiety, or mood disturbances[10, 11]
- Digestive ailments
- Excessive fatigue
- Brain fog
- Joint pain
What Causes Leaky Gut?
Many factors contribute to leaky gut, including chemicals, food sensitivities, pathogens, and GI damage. Once the tight junctions loosen, it triggers a cascade of other conditions in the body. This can happen gradually or suddenly. Genetics can also influence whether a person will have leaky gut. Additionally, there is evidence that the following factors may cause a leaky gut, either independently or working together:
|Dietary Factors||Food additives including nanoparticles, surfactants, and emulsifiers|
|High-fat, high-carb Western diet|
|Specific food components including sugar, gluten, and dairy|
|Infections & Toxins||Environmental toxins|
|Intestinal viral infections|
|“Lifestyle Hypothesis”||Decreased function & diversity of probiotics in the gut flora|
|Drug use (including NSAIDs)|
|“Hygiene Hypothesis”||An overly sterile environment|
|Factors & Conditions in the Body||Genetics|
|Chronic inflammation/autoimmune conditions|
|Enteric Nervous System (ENS) signaling molecules such as serotonin, histamine, & anandamide|
|Traumatic injury, including burns|
|Inadequate supply of oxygen (hypoperfusion) to body tissues|
1. Diet & Nutrition
An article in the peer-reviewed scientific journal BMC Gastroenterology examined the many factors that contribute to a leaky gut. Because few things affect your health as much as your diet, it’s no surprise that several foods were identified to cause leaky gut. Eliminating them from your diet is an effective strategy. The primary offenders that contribute to the development of leaky gut include:
A High-Fat, High-Carb Western Diet
Animal and human studies have associated the typical high-fat (particularly saturated fat), high-carb Western diet with increased leaky gut and higher rates of endotoxemia, which means that toxins are circulating in the blood.[15, 16, 17]
Sugar and artificial sweeteners compromise gut health. One study found that mice fed diets with 30% fruit sugar for eight weeks had intestinal bacterial overgrowth and a loss of tight junction proteins.
Dairy is linked to gastrointestinal disorders. Lactose increases the amount of Clostridium bacteria in the gut, which is associated with irritable bowel syndrome. However, it’s unclear whether dairy increases leaky gut. The main evidence comes from studies showing that when people on the autism spectrum eliminate dairy from their diets, their psychological symptoms improved. Note that these study subjects also eliminated gluten from their diets. More research is required for clear answers.
Gluten contributes to GI irritation, intestinal permeability, and atrophy in the villi in people with gluten sensitivity. Celiac disease, which results from gluten intolerance, has a strong genetic component, but many people do not know ahead of time if they are predisposed to it. Some studies indicate gluten causes GI symptoms even in people without Celiac disease.
Food manufacturers add substances to processed food to increase shelf life or improve the color and texture of food. Several of these, including emulsifiers, solvents, and certain enzymes, have been shown to contribute to leaky gut syndrome.
2. Infections & Toxins
Environmental factors that get into our bodies and stimulate a reaction in the gut include viral infections and toxins in air, food, and water, such as pesticides, fungicides, insecticides, and herbicides, and toxic chemicals in home and hygiene products.
Viral infections that affect the gastrointestinal tract, particularly the intestines, can lead to sudden leaky gut.[23, 24] Scientists still do not know how quickly the body recovers from the increased permeability associated with infection or whether it can lead to permanent gut issues.
The environment is saturated with harmful chemicals and substances, many of which pose a significant risk to your health. Mercury,[25, 26] insecticides, and fungicides all affect intestinal permeability. Glyphosate, a commonly used herbicide, disrupts gut bacteria, which can contribute to the development of a leaky gut.
3. Exposure to Dirt: The Hygiene Hypothesis
The hygiene hypothesis suggests that when children do not get exposed to enough dirt and microbes their immune systems do not develop properly. The scientist who proposed this theory connected it with allergies, but others have expanded it to include autoimmunity, gut problems, and more. A hyper-hygienic lifestyle combined with exposure to environmental toxins, disruptions to gut microbiota, and a lack of vitamin D may lead to leaky gut. This hypothesis states that the combination of these factors may lead to autoimmune diseases.
Another hypothesis behind leaky gut is that various things in a person’s lifestyle promote leaky gut. These include drinking excess alcohol, medication, or stress.
Disruptions to the Gut Microbiota
Increases or decreases in certain species of gut microbes and changes in the overall diversity of microbe species are associated with a leaky gut. People with inflammatory bowel diseases have different microbes than those with a healthy gut. Scientists are studying how changes in microbiota composition interact with the gut barrier.[30, 31] Additionally, some species of Candida are known to disrupt the gut microbiota and may lead to leaky gut.[32, 33]
When the human body metabolizes alcohol, the metabolic byproduct acetaldehyde increases intestinal permeability. Heavy drinking can lead to cirrhosis of the liver and malnutrition, which are associated with leaky gut. Even a single binge drinking episode can increase intestinal permeability.
Medications & Drug Use (Including NSAIDs)
Non-steroidal anti-inflammatory drugs (NSAIDs), such as aspirin, ibuprofen, and naproxen increase intestinal permeability and provoke inflammation. Interestingly, NSAIDs increased gut permeability to a greater level in people who already had irritable bowel syndrome compared with healthy individuals.
Stress negatively affects your health[39, 40] — especially gut health. Psychological stress increases the presence of inflammatory cytokines, which are signaling proteins that contribute to leaky gut. Studies show that both psychological and physical stress compromise the integrity of the intestinal barrier.
Factors & Conditions in the Body
There are factors unique to each person, including genetics, which affect a person’s chances of developing a leaky gut. Major trauma, burns, surgeries, and illnesses can cause your gut to become temporarily leaky. Whether or not these sudden illnesses or trauma result in permanent gut barrier damage remains unclear. The enteric (gut) nervous system (ENS) hormones also play a role in developing a leaky gut.
Genetics affect gut health. Many autoimmune conditions have a genetic component, and autoimmunity is also associated with a leaky gut. Many health conditions are caused by gene-environment interactions, which means that a person may have a genetic predisposition to developing a particular condition, and exposure to certain environmental factors (toxins, foods, trauma, etc) can trigger its development.[39, 43]
Chronic Inflammation & Autoimmune Conditions
It’s generally accepted that a leaky gut leads to autoimmune conditions where the body attacks itself. But a fascinating study found that autoimmune conditions can also attack the gut. This means that a leaky gut can worsen once autoimmunity kicks in, causing a negative feedback loop.
ENS Signaling Molecules
The gut produces chemicals that both inhibit and promote the development of a leaky gut, depending on the situation. These include the hormone serotonin and the pro-inflammatory chemical histamine. The gut also has cannabinoid receptors, and the body’s endocannabinoid neurotransmitters appear to make the gut leakier while plant cannabinoids from marijuana (Cannabis) reduce leaky gut. Cannabis is sometimes used to treat GI issues such as diarrhea, nausea, and gut irritation.
Traumatic Injury to the Body
Leaky gut can result from major trauma, such as a car accident or burns. Severe injuries generally accompany inflammation and sepsis, which can lead to the leaky gut. The more severe the injury, the more severe the intestinal permeability.
Hypoperfusion of Oxygen to Body Tissue
During heart surgery, the body may not receive as much oxygen as it normally does. Medical research found that this hypoperfusion of oxygen to body tissues causes a leaky gut. Most patients’ guts recovered by day five post-surgery, so this is likely a temporary condition in these cases.
How Does Leaky Gut Affect the Body?
A leaky gut can cause digestive conditions, but gastrointestinal illness can also lead to or worsen leaky gut. In other words, gut conditions play upon each other and create a downward spiral. Leaky gut is associated with several health conditions, but not all of them are related to the gut:
- Inflammatory bowel diseases, including Crohn’s disease and ulcerative colitis
- Irritable bowel syndrome (IBS)[30, 38, 49]
- Type 1 (juvenile) diabetes
- Autoimmune conditions including rheumatoid arthritis
- Thyroid conditions including Hashimoto’s thyroiditis[50, 51]
- Allergies and asthma[6, 7]
- Celiac disease and gluten sensitivities
- Autism[19, 52]
- Stress-related psychiatric disorders
- Parkinson’s disease
Is There a Test for Leaky Gut?
The Lactulose/Mannitol Test, sometimes called the Intestinal Permeability Assessment, can test for leaky gut.[49, 54] It’s a simple test in which you collect a baseline sample of urine in the morning, and then drink a mix of two sugars (lactulose and mannitol). Six hours later, you collect another sample of urine which a lab will analyze. If your gut is leaky, you will have high amounts of the large sugar lactulose in your urine. If your gut is intact, the sugar will remain mostly in the digestive tract.
Another common test is called the blood zonulin test. Zonulin is a protein that regulates the permeability of the gut epithelial layer. If zonulin antibodies are present in the blood, the body is fighting against its own proteins, and the gut barrier may be leaking. Some healthcare providers will also test the blood for occludin and actomyosin protein antibodies, with similar reasoning. These also play a role in protecting the gut barrier, and antibodies indicate the body is attacking its own gut barrier proteins.
Natural Remedies for Leaky Gut
Fortunately, there are natural health solutions for a leaky gut that ease the burden of living with the condition. Carefully monitoring what goes into your body is one of the best remedies for managing a leaky gut. Better yet, you can proactively prevent your gut from becoming leaky in the first place by following a healthful diet, engaging in intermittent fasting and body cleanses, and avoiding toxins and chemicals.
Detox & Fasting for Leaky Gut
If you have leaky gut or suspect you do, experimenting with different diet options allows you to see what works best for you. To see what foods your body likes and does not like, I recommend water fasting for a week or a few weeks to clean out your gut. This can change your life!
After eliminating all food for a short period, you can gradually introduce foods back into your diet one at a time and identify any unpleasant reactions. If water fasting does not work for you, then perform a strict, clean, plant-based detox diet for a week and then gradually introduce foods back one by one.
Is There a Leaky Gut Diet?
Following a healthy diet is one of the most effective measures to help manage leaky gut. Some foods help leaky gut, including fermented foods which contain natural probiotics. Avoiding gluten or dairy can ease symptoms for some people. Most non-starchy vegetables contain high levels of antioxidants and high fiber which ease digestive irritation.
One of the most popular leaky gut diets is the low-FODMAP diet. FODMAP stands for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, which are short-chain carbohydrates. Gut bacteria easily digest FODMAPs which means they ferment during the digestive process. Studies have shown that a low-FODMAP diet improved digestive symptoms for non-celiac gluten sensitivity, and other studies found parallel results for irritable bowel syndrome.[56, 57] Since digestive symptoms are similar among these conditions, it is likely a low-FODMAP diet can ease leaky gut symptoms.
Other diets proposed to help with leaky gut and other GI conditions include the AID-IBD (anti-inflammatory inflammatory bowel disease) diet,[17, 58] a modified form of the specific carbohydrate diet. The AID-IBD diet aims to restore a healthy gut microbiota to ease symptoms and promote healing.
The paleo diet, which is high in meat, is sometimes recommended for improving digestive symptoms. Research suggests that collagen, a protein from animals, can help repair tight junctions and possibly repair leaky gut. Regardless, consuming meat isn’t without its tradeoffs, as multiple studies have found that eating meat can increase your risk of developing inflammatory bowel disease.[60, 61] In contrast, studies show that a plant-based diet that’s high in fiber and fruits is associated with a lower risk of developing IBD.
What Are the Best Supplements for Leaky Gut?
- Vitamin D3
- Aloe Vera
There are several herbs and supplements that can improve a leaky gut. People with inflammatory bowel disease often have vitamin D deficiency. A few animal studies found that vitamin D3 supplementation reduced the number of bacteria that got through a leaky epithelial barrier and improved the tight junctions.[62, 63]
L-Glutamine and curcumin support the intestinal environment by reducing the irritation and the oxidative stress that weakens tight junctions. Aloe vera is known to lower gastric acid secretion levels in lab rats. Aloe also promotes a healthy balance of gut microbes.[67, 68] Quercetin, a plant pigment that comes from onions, apples, and citrus fruits, also supports the gut barrier.[69, 70]
Zinc is an essential trace mineral that supports the immune system and the function of the tight junctions, especially in the case of a zinc deficiency. One study found that supplementation with zinc sulfate decreased the levels of lactulose in the lactulose/mannitol test in Crohn’s disease patients, indicating zinc improved gut function.
Do you have experience with a leaky gut? What insight can you offer? Leave a comment below and share your thoughts.