Leaky gut syndrome doesn't sound like the kind of thing anyone wants to have, yet we're hearing about it a lot lately. If you look across the vast plains of the Internet, you'll find all kinds of blogs and alternative health sites warning about leaky gut syndrome, which is often described as a condition in which the lining of the intestines has become more permeable or porous. Some places even suggest it could be associated with everything from food allergies and nutritional deficiencies to autoimmune conditions, fatigue, and joint pain.
But what actually are we talking about here? Here's what we know (and don't know).
Here’s the problem with “leaky gut syndrome” as a diagnosis.
Leaky gut syndrome is not a formally recognized medical condition. That doesn't mean that people aren't experiencing frustrating or debilitating symptoms; it just means that those symptoms are not traditionally thought to be caused by a leaky gut.
"Leaky gut syndrome is not a true medical diagnosis," Donald Kirby, M.D., gastroenterologist and director of the Center for Human Nutrition at Cleveland Clinic, tells SELF. Aparajita Singh, M.D., a UCSF Health gastroenterologist and associate professor of gastroenterology at University of California, San Francisco, agrees: "I’ve never told a patient, 'You have leaky gut syndrome,' but I've heard it many times," she tells SELF.
Of course, that doesn't mean a person's symptoms are any less real. People commonly associate a wide variety of symptoms with a leaky gut, Dr. Kirby says. That includes things like:
- Abdominal pain
- Gas and bloating
- Brain fog
- Memory loss
- Skin rashes
- Joint aches and pains
Medical experts are wary of connecting these symptoms with something that is not a recognized condition, emphasizing instead that someone with these symptoms be seen by a gastroenterologist who can help diagnose the problem.
That's because many of these symptoms could easily be signs of other gastrointestinal conditions, Felice Schnoll-Sussman, M.D., director of the Jay Monahan Center for Gastrointestinal Health at NewYork-Presbyterian and Weill Cornell Medicine, tells SELF. Those could include irritable bowel syndrome (IBS), food intolerances or allergies, small intestinal bacterial overgrowth (SIBO), and (in rare cases) an inflammatory bowel disease (like Crohn's disease and ulcerative colitis).
So, where does the concept of leaky gut syndrome come from?
The idea of leaky gut syndrome is based on the concept of intestinal permeability, something we're only beginning to understand. The primary way your body keeps food particles, bacteria, and toxins—actual toxins—inside the intestines (and outside the bloodstream) is the intestinal membrane, which is lined with fingerlike villi, Dr. Singh explains. The thinking goes that having a weakened intestinal barrier causes those potentially harmful things to leak out, and possibly cause all kinds of symptoms and issues.
It is true that, over the past two decades or so, our understanding of the way this barrier functions has evolved. Traditionally, it was thought that the cells of the intestinal lining are connected by tight junctions, "and you think of tight junctions like mortar between two bricks," Dr. Kirby says. But experts now recognize that those tight junctions "are more like canals, and they can open and close. So they can, under certain circumstances, get a little weaker," he describes.
There is naturally some level of permeability in the membrane to allow for the flow of electrolytes, water, and nutrients into the bloodstream. But there's also evidence that the junctions are looser in people who've undergone treatment for cancer, especially chemotherapy, Dr. Kirby says. The balance of bacteria naturally present in your gut may also play a role in permeability, Dr. Schnoll-Sussman says. There is weaker evidence that diet—including processed food, caffeine, and alcohol intake—as well as the use of NSAIDs may increase the permeability of the membrane, Dr. Singh says. But for now, these are all still just theories, she notes.
Even in health conditions associated with increased intestinal permeability (which, remember, is still an evolving concept), it seems to be more of a by-product of the disease than a cause. We have the best evidence that intestinal permeability is a factor when it comes to immune-related conditions like celiac and Crohn's disease. In patients with celiac disease, for example, we know that eating gluten triggers an immune response that damages the body's intestinal lining. This, in turn, loosens the intestinal junctions. In this specific case, it's suspected that any increase in permeability is a by-product of celiac rather than the cause, Dr. Kirby explains.
Some research suggests that people with IBS also show increased permeability, although it's not yet understood why or how. Conditions like these "may lead to inflammation of the intestine and, as a consequence, the intestinal lining may be damaged, which can lead to increased intestinal permeability and passage of bacteria and toxins into the bloodstream," Dr. Schnoll-Sussman says. "This is [a] hypothesis, however," she says—and even if there is increased permeability, it hasn't been "definitely proven" that it causes disease.
Even if intestinal permeability is something that occurs and even if it leads to the passage of bacteria and toxins into the bloodstream, it's not clear how that would cause the wide range of symptoms that people often associate with a leaky gut—especially those not directly related to the gut, like brain fog, rashes, and joint pain.
There also aren't medically recognized ways of testing for leaky gut syndrome or intestinal permeability. Some alternative health providers may suggest a notoriously unreliable test to look at the level of indigestible sugars (lactulose and mannitol) in your urine. Some people might also use a blood test to look for markers of the protein zonulin, which we know is involved in regulating permeability and is elevated in people with celiac disease. But, again, we don't really know how intestinal permeability works in these conditions or how an elevated zonulin level would contribute to celiac disease (which is actually diagnosed with other blood tests for specific antibodies)—not to mention what a specific result on this test would mean for people without celiac disease.
For all of these reasons, medical experts advise you to be skeptical of any treatments that claim to help with leaky gut syndrome. "Proponents [may] use [leaky gut syndrome] as an opportunity to sell a number of health-related remedies which can be potentially harmful and most are not FDA-approved," Dr. Kirby says. Some alternative health sites recommend supplements like probiotics and enzymes or encourage diets that cut out gluten and sugar-containing foods (including both fruits and processed foods) or recommend only consuming raw, unpasteurized dairy.
Dr. Singh says it's usually OK for people to experiment by cutting back on their caffeine or alcohol use on their own. But Dr. Kirby advises people to enlist the help of a doctor or registered dietitian when making more drastic dietary changes, and to steer clear of supplements sold online under the guise of treating leaky gut syndrome.
Here’s what to do if you’re experiencing symptoms.
Any new or troubling gastrointestinal symptoms warrant a chat with your doctor and possibly a specialist, like a gastroenterologist. "It is imperative that people who present with symptoms associated with leaky gut work with a medical practitioner who can initially evaluate them for other serious diagnoses that may present with similar symptoms," Dr. Schnoll-Sussman says. But it's unlikely that you'll walk away with a diagnosis of leaky gut syndrome or increased intestinal permeability.
When a patient comes to her asking about leaky gut syndrome, Dr. Singh says, "I don’t get fixated on the diagnosis. The first thing I do is listen." Your doctor or gastroenterologist will likely then ask you about your symptoms and your family history of gut illnesses. From there, they may order diagnostic tests (like a blood test to look for signs of celiac disease or a breath test to look for signs of SIBO). If an allergy is suspected, your doctor may send you to an allergist for more specialized treatment, Dr. Kirby says. Or your doctor may ask you to keep track of your symptoms and what you eat in a food diary to look for patterns and may have you try eliminating certain foods (an elimination diet) for a period to see if that helps, Dr. Singhs says.
Ultimately, whatever is causing your issues, you deserve to have real answers—and real relief.