Leaky Gut Syndrome: What Is Known and Unknown?

Leaky gut syndrome is not a recognized medical condition. There is no approved diagnosis or treatment method for it. People who discuss leaky gut think the gut lining has become more permeable ("leaky"), allowing substances and microbes to pass from the gut into the bloodstream and perhaps farther into the body.

The gut lining can become more permeable in various gastrointestinal conditions. This permeability might be linked to abdominal pain, bloating, and diarrhea. People who experience these symptoms need to work with their healthcare providers to understand the underlying cause and how it should be treated.

Defining Leaky Gut Syndrome and Gut Permeability 

The organs of the digestive system have an inner lining. That lining has many roles, including absorbing nutrients and other substances from foods and drinks. It is also a barrier that prevents potentially harmful substances from passing through it and into intestinal tissue.

When this lining has gaps, it becomes more permeable. Some things passing through the digestive system may then work their way past the lining and into the intestinal tissue. These substances could then move on to enter the bloodstream.

Undigested food particles, bacteria, or toxic substances can enter body tissues this way. This is why it's important that the digestive system's lining stays as intact and as undisturbed as possible.

Do Providers Recognize Leaky Gut Syndrome?

Leaky gut syndrome is not a recognized diagnosis by the medical community. It is more commonly discussed in "lay" literature, meaning nonmedical professional materials.

That doesn't mean that intestinal permeability is not possible or is not a problem. The gut lining, in general, has a certain amount of permeability. It has to allow nutrients to pass through it. However, significant permeability isn't common or believed to cause a wide variety of symptoms outside of the digestive system.

Leaky gut is also something that is not diagnosable with stool tests or blood tests. No test is universally recognized as reliable in diagnosing intestinal permeability. Some specialized testing is being studied, but there isn't enough information yet to use these tests in patients with any certainty.

Associated Symptoms and Conditions

Even though leaky gut is not a recognized condition, it is known that the intestinal lining can become damaged and become more permeable.

Some symptoms often associated with leaky gut are:

• Abdominal pain
• Bloating (abdominal discomfort with feeling of fullness or tightness)
• Diarrhea
• Distension (visible outward swelling of the abdomen)
• Dyspepsia (indigestion)
• Early satiety (feeling full after eating only a little)
• Nausea

Some conditions have been connected to permeability in the inner layer of the digestive system. Less is known about whether or not it can be said for certain that the permeability either affects or plays a role in the cause of these conditions. These include:

• Celiac disease (an autoimmune condition with sensitization to gluten)
• Functional dyspepsia (FD) (recurring indigestion without known cause)
• Graft-versus-host disease (a stem cell or bone marrow transplant attacks the recipient)
• Human immunodeficiency virus (HIV)/AIDS (an infection that attacks the immune system)
• Inflammatory bowel disease (IBD) (ulcerative colitis or Crohn's disease, characterized by inflammation in the bowel)
• Irritable bowel syndrome (IBS) (a disorder of the brain-gut connection)
• Multiple organ dysfunction syndrome (two or more organ systems are not working correctly due to complex causes)
• Type 1 diabetes (an autoimmune form of diabetes)

Link Between the Gastrointestinal (GI) Tract and Other Organs 

There is little evidence that permeability in the intestines affects organs outside the digestive tract. Research has not supported the idea that a leaky gut could lead to symptoms or cause conditions outside the digestive system.

However, extraintestinal symptoms and conditions (those in other parts of the body) are still sometimes believed to be linked to a leaky gut, even without good evidence. Some of these symptoms include:

• Allergic and autoimmune reactions, such as asthma, skin rashes, and swelling
• Joint and muscle conditions, such as chronic joint or muscle pain, chronic fatigue syndrome, and fibromyalgia
• Neuropsychiatric conditions, including memory problems, mood swings, and agitation
• Skin conditions, such as psoriasis, atopic dermatitis, acne, and atopic eczema
• Infections, such as frequent respiratory infections, vaginal infections, and recurrent bladder infections
  

How to Self-Manage Leaky Gut Syndrome

One way to manage leaky gut is to make dietary changes. This can include removing foods that have a negative impact on the gut microbiome (the community of microbes that live in the gut), while adding in foods that will have a positive effect.

Overall, eating a lower-fat diet that includes fruits, vegetables, and fiber while reducing excess fats, carbohydrates, and sugar may help improve digestive health.

Starting a new way of eating can be challenging. Making small changes weekly is one strategy that may help. It may also be helpful to keep a food diary in a journal or through an app. Tracking symptoms after meals could also give some clues as to foods that might be more or less helpful with symptoms.

Food groups that people with intestinal permeability might consider avoiding include:

• Alcoholic beverages
• Artificial sweeteners
• Excessive amounts of animal protein (meat)
• High-fat foods
• Highly processed foods
• Sugary foods
  

Foods that might be included in the diet to help improve intestinal permeability include:

• Dietary fiber (which the body can use to produce short-chain fatty acids)
• Plant-based protein
• Unsaturated fats
  

Psychological stress can affect gut health and the gut microbiome, as well as increasing the risk of anxiety and depression. Poor mental health, in turn, can lead to making unwise dietary choices that do not support gut health. Managing stress whenever possible is also important in maintaining good digestion.

Staying hydrated, getting quality sleep, and stopping smoking are other things that may help in reducing irritation and/or inflammation in the gut.

Leaky Gut Syndrome Treatment Under Provider Supervision 

There is no approved treatment for people suspected of having or known to have intestinal permeability. However, healthcare providers such as gastroenterologists and dietitians may suggest ways to help decrease permeability.

Probiotics (beneficial gut microbes) have not been proven to help on a widespread basis, but there are two specific circumstances in which they were studied. A trial was done in adults with obesity. Probiotics that contain two different strains of a bacteria called Bifidobacterium helped these people with intestinal permeability.

The other example is from a mouse study. It involved a proprietary strain of probiotics called VSL#3. The mice with medication-induced colitis had less intestinal permeability when given VSL#3.

VLS#3 has been used in people with ulcerative colitis, but whether it will be effective for any particular person is unknown. A person could try it to see if it helps, but it is expensive, and little evidence supports its usefulness.

You might see a registered dietitian to manage gut permeability. In some cases, a dietitian will recommend a diet that has been shown to have a beneficial effect on overall health, such as the Mediterranean diet.

A mental health professional may also help manage the emotional aspects of leaky gut. Having a wide variety of symptoms without a specific cause can postpone a diagnosis and treatment, affecting emotions. There is no evidence about what type of therapy might be most helpful, but a mental health professional experienced in people with chronic illness may be able to make suggestions.

Summary

"Leaky gut" is not a recognized medical condition. There is no accepted way to diagnose or treat leaky gut syndrome. However, the gut can become more permeable, leading to a risk of symptoms inside and outside of the digestive tract.

People experiencing digestive issues should see a healthcare provider for symptom relief and a possible diagnosis. This includes people already living with a digestive or immune-mediated condition who are experiencing new or ongoing symptoms.