How Intestinal Permeability Relates to Crohn's, Celiac, Allergies, and More

By Cathy Wong 

 Medically reviewed by Robert Burakoff, MD

Certain symptoms are related to leaky gut (or increased intestinal permeability). However, leaky gut syndrome itself isn't a recognized medical condition. Common symptoms include abdominal pain, bloating, and diarrhea. If you have these symptoms, check in with a healthcare provider to be assessed for related conditions that are associated with leaky gut.

Common disorders associated with leaky gut are gastrointestinal disorders like Crohn's disease, celiac disease, and inflammatory bowel disease. Food allergies, skin conditions, and more are linked to leaky gut as well. However, more research is needed to fully understand the connections.

What is clear is that leaky gut can be a factor in chronic infections or inflammation if contents of digestive tract get into the bloodstream. Leaky gut may even be implicated in autoimmune disorders. This article covers leaky gut symptoms, risk factors, and related conditions. It also discusses when to see a healthcare provider and how to find support.

Symptoms of Leaky Gut Syndrome

Your gut needs to be somewhat permeable to absorb water and nutrients, but not too leaky to let everything through. After all, your intestines provide a barrier to keep beneficial bacteria and infectious agents inside the gut. This barrier forms an important part of your immune system.

Although leaky gut is not a recognized medical diagnosis, it is used in alternative health circles. According to the concept of leaky gut, increased intestinal permeability causes various health symptoms. While the intestinal lining can be dysfunctional, it may or may not contribute to illness.

Everyone is different when it comes to leaky gut. Sometimes leaky gut can be a predictor of a later condition, but you can also have a leaky gut without having an underlying condition. Some people with leaky gut don't have any symptoms.1

If you've got gastrointestinal symptoms, you may be wondering if you have small intestinal bacterial overgrowth (SIBO) or leaky gut. Both SIBO and leaky gut can cause similar symptoms because they are tied to the same conditions like celiac disease, Crohn's disease, and irritable bowel syndrome.

Digestive Symptoms

As the intestinal barrier breaks down, it can create problems in the digestive system. It can affect the normal functioning of how nutrients and compounds move through the lining of the intestine, causing a number of symptoms.2

Common gastrointestinal symptoms related to leaky gut include:

• Abdominal pain

• Bloating

• Diarrhea3

• Constipation4

• Gas5

Digestive symptoms are the more immediate symptoms of leaky gut. When harmful agents leak further through the intestine, they can enter the bloodstream. From there, they can get to any part of the body, causing a number of other symptoms throughout the body.

Cognitive Symptoms

Leaky gut symptoms don't just stop in the digestive tract. They can affect your thinking too, on a pathway referred to as the gut-brain axis. Communication goes both ways on this axis, so it's hard to tell what is a cause and what is a consequence.6

Increased intestinal permeability has been associated with these mental health symptoms:6

• Depression

• Abnormal behavior

• Abnormal thoughts

• Poor memory

• Anxiety

• Changes in mood

Respiratory Symptoms

The health of your lungs may be more closely linked to your gut than you realize. The connection is your immune system. The health of your gut may help determine how healthy your lungs are.

Leaky gut has been linked to these respiratory symptoms:

• Asthma7

• Shortness of breath8

Muscular and Skeletal Symptoms

Your muscles and bones can become inflamed in response to harmful agents like bacteria getting into your blood through a leaky gut.

A highly permeable gut is associated with pain throughout your body, including:

• Chronic joint pain9

• Chronic muscle pain10

Infections and Other Symptoms

The immune system in your gut is your first line of defense against a number of disease-causing organisms. When bacteria leaks from your gut into your bloodstream, your immune system has to work to fight off the invaders. This may leave you more susceptible to other infections, including:

• Frequent colds

• Recurrent vaginal infections

• Recurrent bladder infections11

The inflammation and other effects of leaky gut are also related to these symptoms:

• Fatigue12

• Skin rashes13

Risk Factors

Many factors can have an effect on leaky gut, from your stress levels to your circadian rhythm.3

The risk of getting leaky gut goes up if any of the following things apply:

• Chronic stress: Not all stress is bad, but too much stress can be hard on your body. Stress hormones released when your sympathetic nervous system is activated can increase intestinal permeability.14

• Small intestine bacterial overgrowth: SIBO occurs when your small intestine becomes populated with bacteria from your large intestine (colon). The bacteria can disrupt the proper function of the intestinal barrier, leading to leaky gut.15

• Exposure to environmental contaminants: Research has shown that heavy metals cause oxidative stress, which damages cells. This damage increases intestinal permeability and causes dysbiosis—an imbalance in gut microorganisms. These damaging impacts have been implicated in mental health disorders. In addition, bisphenol A, a manmade chemical used in plastics, has been known to increase gut leakiness. Air pollutants, too, can disrupt the tight bond in the intestinal lining, causing more leakiness.16

• Excess alcohol use: Alcohol and its metabolites (the substances your body processes from alcohol) are not good for your gut. Research has determined that they can cause inflammation, cell damage, and cell death, all of which can result in increased gut leakiness.17

• Poor diet: Science has shown that a poor diet can make your gut leakier. Foods high in saturated fat, processed foods, and foods with refined sugar harm your intestinal barrier, resulting in more leakiness. In contrast, a good diet can help your gut barrier. Foods found in the Mediterranean diet—ones with high dietary fiber and low levels of saturated fat—can actually help make the gut barrier stronger.14

• Use of nonsteroidal anti-inflammatory drugs (NSAIDs) and other medications: NSAIDs work well to reduce pain, but they can be damaging to the gut, leading to increased intestinal permeability.18 Necessary in the treatment of infections, antibiotics are another group of medications that cause imbalance in the gut. Antibiotics target bacteria, both harmful and beneficial bacteria. When the helpful bacteria in the gut die off, inflammation occurs and disrupts the function of the gut barrier.19

Related Conditions

Changes in intestinal permeability are often related to digestive disorders. However, leaky gut can be involved in autoimmune diseases, skin disorders, and other conditions.

Crohn's Disease

Crohn's disease causes pain and inflammation (swelling) of the digestive tract. Its causes are unknown, but it has been shown to alter how well the intestinal barrier works. A highly permeable barrier (or leaky gut) occurs when the cells of the intestinal wall lose their ability to be an effective barrier.

Research has found that people with leaky gut may be more likely to develop Crohn's disease than people without leaky gut. These findings suggest that leaky gut may be a reason why people develop Crohn's disease.1

Celiac Disease

People with celiac disease have a reaction to gluten. The intestines are a big part of your immune system and are affected by this autoimmune disease. Research has found a strong connection between leaky gut and celiac disease.2

Leaky gut in celiac disease can result from consuming gluten. Sticking to a gluten-free diet may help reduce and even stop leaky gut.2

Irritable Bowel Syndrome

Irritable bowel syndrome (IBS) affects the gastrointestinal tract, causing pain and other symptoms. Types of IBS include the constipation subtype, the diarrhea subtype, the mixed subtype, post-infection IBS, and post-diverticulitis IBS.

People with diarrhea-predominant IBS and post-infection IBS seem to be the most affected by leaky gut. The bacteria and antigens leaking through the gut in IBS may lead to chronic diarrhea and abdominal pain. The leakier the gut, the more severe the symptoms.20

Food Allergies

There is a good amount of evidence linking leaky gut to food allergies. When there is increased permeability, food allergens can leak through the outer layer of the gut, activating the submucosal immune system. The body's response to the allergens makes the gut even leakier. People with atopic diseases like asthma or allergic rhinitis may be particularly affected.21

Other Conditions

Research has found an association between leaky gut and a number of other conditions. It's still too early to say if there is a cause and effect in this relationship. Having one of the following conditions may increase your risk of leaky gut.

• Autism: Gastrointestinal problems begin in childhood in people with autism. Leaky gut, diarrhea, and constipation are common.22

• Obesity: Being largely overweight may make your gut more prone to leaks. People with certain conditions like IBS may tend to have a higher body mass index (BMI) and leakier guts than people without IBS. However, more research is needed on how exactly BMI and leaky gut are related.20

• Body pain: There is some indication that people with chronic fatigue syndrome or fibromyalgia may have more intestinal barrier dysfunction, leading to increased permeability.10

• Autoimmune diseases: Research has found a link between autoimmune diseases and leaky gut. Lupus and multiple sclerosis are associated with a higher risk of increased intestinal permeability.23

• Ulcerative colitis: Like Crohn's disease, ulcerative colitis is an inflammatory bowel disease. If you have an inflammatory bowel disease, you're more likely to experience leaky gut too.2

• Skin conditions: Your skin is more closely related to your gut than you may realize. Imbalances in the gut microbiome can cause leaky gut and have been linked to acne, eczema, psoriasis, and hives.24

• Arthritis: Inflammation and the gut are closely related. A leaky gut may be related to the development of and progression of osteoarthritis.9 Another form of arthritis, rheumatoid arthritis, also has ties to gut health. A leaky gut may be involved in the development of rheumatoid arthritis.25

• Infections: Intestinal infections like Giardia (a parasitic intestinal infection) can increase intestinal permeability.26

• Liver dysfunction: A healthy gut barrier is important in keeping your liver healthy. The liver is the second firewall against potentially harmful substances from the gut. Leaky gut is common in people with liver damage.27

Complications

A leaky gut can expose your immune system to more disease-causing organisms than when your gut barrier is functioning properly. Minor complications include bloating, cramps, fatigue, food allergies and sensitivities, gas, and headaches.

If left untreated, leaky gut may lead to more serious complications, like autoimmune conditions, depression and other mood disorders, diabetes, inflammatory bowel disease, and multiple sclerosis.3

Research has shown that a leaky gut may increase the risk of metabolic diseases. Metabolic diseases are very common in the population and include obesity, diabetes, hyperlipidemia (high blood lipids), and nonalcoholic fatty liver disease.

Metabolic diseases damage the ability of the cells and mucous membrane of the gut lining to work as a barrier, creating more leakiness. The leakiness then makes symptoms worse, creating a cycle of inflammation, abnormal metabolism, and leakiness.28

Other research suggests that the body's long-term response to gut inflammation related to dysbiosis and leakiness can lead to the development of rheumatic diseases, like rheumatoid arthritis. However, diet and a healthy gut environment may be able to improve gut barrier function.25

If You Think You Have Leaky Gut

If you think you have leaky gut syndrome or symptoms of related disorder, talk to your healthcare provider. Healthcare providers can run tests to determine the cause of your symptoms.

The standard test for leaky gut syndrome is the mannitol and lactulose test. Both are water-soluble molecules that the body can't use.29 Mannitol is easily absorbed by people with healthy intestinal linings. Lactulose is a larger molecule and is only slightly absorbed.

For the test, a person drinks a mannitol and lactulose solution. Urine is collected for six hours, and the amount in urine reflects how much of each was absorbed by the body.

A healthy test shows high levels of mannitol and low levels of lactulose. If high levels of both molecules are found, it indicates a leaky gut condition. If low levels of both molecules are found, it indicates general malabsorption of all nutrients.

Support

Leaky gut syndrome is not a recognized medical disorder, but it's symptoms are real. If you need support beyond what your healthcare provider can give you, reach out to a local or online leaky gut support group. Mental health professionals can also help you manage symptoms.

What you eat can have a big impact on symptoms. Diets that promote healthy eating patterns, like the Mediterranean diet, may be able to help increase the strength of your intestinal barrier.25

Summary

Leaky gut, or increased intestinal permeability, may be a symptom of a gastrointestinal disorder. However, it could also signal other underlying conditions that require treatment.

There is limited research about leaky gut syndrome. It's also important to note that self-treating a condition and avoiding or delaying standard care may have serious consequences. If you're experiencing any symptoms or are concerned about your health, consult a healthcare provider.

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Additional Reading

Lipski E. Digestive Wellness. Keats Publishing/McGraw Hill, 2001.

By Cathy Wong
Cathy Wong is a nutritionist and wellness expert. Her work is regularly featured in media such as First For Women, Woman's World, and Natural Health.