Does a Leaky Gut Cause Disease?

Your gut is home to trillions of bacteria, yeast, viruses and fungi. That unique mix of microorganisms plays an important role in many elements of health, from digestion to emotional well-being. And while your intestinal barrier separates your gut from the rest of your body, it’s not an impenetrable fortress.

“The gut is supposed to be somewhat permeable, or leaky,” says UNC Health allergist/immunologist Erin Steinbach, MD, PhD. “It absorbs nutrients and gets rid of waste.”

“Sometimes you’ll have a leakier gut than at other times,” adds UNC Health rheumatologist Amanda Nelson, MD. “It can depend on diet, disease or other stimulus. That change in permeability is a natural process.”

But what happens if the barrier becomes too permeable? Could your gut lining put you at risk for disease? Drs. Steinbach and Nelson explain.

What Is Leaky Gut Syndrome?

Leaky gut syndrome is a term used to describe increased intestinal permeability, but it’s not an actual medical diagnosis.

“We still need lots of research on what a leaky gut means,” Dr. Steinbach says. Even without a definition, “there is a general understanding that when the intestinal barrier is less selective about what it lets across, it could cause disease.”

Researchers have found an association between increased intestinal permeability and gastrointestinal conditions including celiac disease and Crohn’s disease, a type of inflammatory bowel disease, though it may be a symptom or result of those diseases rather than a cause.

Increased intestinal permeability has also been linked to asthma, multiple sclerosis, depression, chronic fatigue syndrome and pancreatitis, among other non-gastrointestinal conditions—though in all cases, these links require additional research.

“It’s clinically hard to say what a leaky gut means at this point,” Dr. Nelson says. “It could be a risk factor for other conditions. It could be a symptom. You could have it and there might be no relation to disease.”

Testing for a leaky gut is also limited. Researchers typically use urine or blood tests to look for sugars, bacteria or other markers that should be low in a person with typical intestinal permeability, but these tests are not offered in a clinical setting.

Drs. Nelson and Steinbach are two of the researchers trying to understand what happens when the gut’s barrier isn’t working as it should. Dr. Nelson is studying the link between increased intestinal permeability and osteoarthritis, while Dr. Steinbach is considering its effect on peanut allergy.

Leaky Gut and Osteoarthritis

Osteoarthritis causes pain, stiffness, tenderness and a loss of range of motion in the affected joints, and it worsens over time. Risk factors include age, obesity, genetics, and joint injury and stress. Intestinal permeability may be involved in the cause and progression of the disease as well.

Lipopolysaccharide (LPS) is a molecule that affects the body’s inflammatory response. It is normally found in the gut; however, it seems to be present at higher levels in blood samples of people with osteoarthritis.

It’s possible that too much LPS is leaking from the gut and causing arthritis to develop, Dr. Nelson says.

While it’s not yet clear what an appropriate amount of LPS would be, higher LPS levels have also been linked to obesity, a risk factor for osteoarthritis.

Dr. Nelson is leading a five-year research project funded by the National Institutes of Health to further investigate the association between increased intestinal permeability and multi-joint osteoarthritis. The project includes partners at NC State University’s College of Veterinary Medicine, who are investigating the same link in pet dogs.

“Dogs get osteoarthritis and obesity just like people,” Dr. Nelson says. “We’ll test whether a probiotic can alter the gut microbiome or intestinal permeability in dogs.”

It’s too early to say how the research would affect clinical treatment for people or pet dogs with osteoarthritis, she says.

Leaky Gut and Peanut Allergy

Peanuts are one of the most common causes of childhood food allergies. But unlike other food allergies, it tends to persist into adulthood.

“As of now, we only have one FDA-approved treatment to manage reaction to peanuts,” Dr. Steinbach says. “People with this allergy have to avoid peanuts, but lots of kids have an accidental exposure and a bad reaction.”

Dr. Steinbach noticed several small studies that found a correlation between increased intestinal permeability and a more severe allergic reaction to peanuts. Severe allergic reactions, called anaphylaxis, are potentially fatal.

“Something about the intestinal barrier is making those reactions more severe,” Dr. Steinbach says. “We’re working to understand what makeup of the barrier is causing that response specifically to peanut.”

Dr. Steinbach’s lab uses intestinal cells from mice and donated cells from humans to measure the permeability of the intestinal barrier in the presence of peanut.

“When we know how peanut affects the leakiness of guts, we could calm the immune system, calm the leaky barrier and better prevent severe allergic reactions,” Dr. Steinbach says. “That would make peanut allergy a chronic disease that’s bothersome rather than life-threatening.”

How to Improve a Leaky Gut

Given the many conditions linked to increased intestinal permeability, you may be wondering what you can do to improve the health of your intestinal barrier. For now, Drs. Nelson and Steinbach recommend following the basic tips known to boost gut health, which may also help to improve the gut lining.

“A healthy diet has the biggest influence on the microbiome,” Dr. Nelson says. “Avoiding processed food, being physically active and staying at a healthy weight will help the gut.”

Also avoid taking any unnecessary antibiotics, which affect the gut bacteria, Dr. Steinbach says.

There is some evidence that alcohol, antacids, and nonsteroidal anti-inflammatory drugs such as aspirin and ibuprofen affect the intestinal lining, but there are no recommendations yet for steering clear of these drugs completely.

So, until researchers have more evidence on how to strengthen the intestinal barrier, healthy habits hold the key.

“It’s the same advice doctors have given for years and years: Get enough sleep, minimize stress, exercise, and eat a healthy, varied diet,” Dr. Steinbach says.

If you have questions about your gut health, talk to a doctor. Need a doctor? Find one near you.