Is Leaky Gut Real?

Does leaky gut cause the wrong particles to escape your intestine?. Dorling Kindersley/Getty Images

When you hear the phrase "leaky gut," you might have an image of gigantic undigested food particles (with maybe some dancing bacteria) flowing willy-nilly from your intestines into your bloodstream, potentially causing havoc with everything from your joints to your brain (yikes!).

While this may be a popular, evocative image (who wouldn't be at least a little frightened by it?), it's not exactly realistic.

Frankly, it's not even close.

The truth is, medical research does show that some people's digestive systems become permeable, or "leaky," but researchers aren't sure exactly why ... and they're not exactly sure what happens as a result, either. As for how it might actually affect you, that's unfortunately even less clear.

Let's start with what we do know.

What Is Leaky Gut?

Your small intestinal lining is made up of interconnected cells that typically have very tight junctions, making the entire system effectively leakproof except for the broken-down nutrients (think vitamins, minerals, fatty acids and amino acids) that are supposed to pass through it into your bloodstream.

According to medical research, certain medical conditions (including celiac disease and inflammatory bowel disease) can cause these tight cell junctions to loosen, potentially providing an opening for somewhat larger molecules (not giant, just a little bit bigger) to move into your bloodstream.

What's less clear is whether these molecules can cause problems.

Alternative medicine practitioners believe they can. They believe these larger molecules — which may include microscopic fragments of partially digested food — can trigger an inflammatory reaction in the body, since the body's immune system recognizes them as invaders and gears up to fight them.

According to the theory behind the condition, leaky gut syndrome also can allow toxins and disease-causing bacteria to slip from the intestine into the blood stream, further exacerbating the inflammation.

Signs of Leaky Gut

Here's a list of the symptoms most often associated with leaky gut:

According to the theory, these leaky gut symptoms are caused or spurred on by inflammation created as your body fights these "foreign invader" molecules leaking from the small intestine.

You might have noticed that the symptoms of leaky gut syndrome look an awful lot like symptoms of celiac disease or signs of non-celiac gluten sensitivity. There's actually symptomatic overlap with a wide variety of conditions, ranging from irritable bowel syndrome to fibromyalgia. This may mean your symptoms are caused not by "leaky gut" at all, but by a diagnosable (and potentially treatable) medical condition.

In addition, while medical science has shown that some people have "leakier" small intestines than others due to conditions such as celiac or Crohn's, as of yet there's no firm evidence linking "leaky gut" to any specific symptoms. So while your intestine may be "leakier" than average, that leakiness may not be causing these specific symptoms, or it may have another effect that hasn't been discovered yet.

Okay, You Think You Might Have Leaky Gut. What Now?

You can be tested for leaky gut. To do so, you drink a pre-measured solution containing two different types of sugar molecules (lactulose and mannitol), and then collect your urine for the next six hours.

The leakiness of your gut is determined by how much of these two sugars you excrete in your urine.

However, it's not clear leaky gut testing will tell you anything useful.

As I said above, medical research has shown people with active celiac disease (but not those with gluten sensitivity) have increased intestinal permeability. In fact, one of the celiac disease drugs in development aims in part at tightening junctions between cells in the small intestine, in the hope that doing so will reduce damage from gluten exposure.

However, the investigators developing the drug, BL-7010, don't think it will allow people with celiac to eat large amounts of gluten again; at best, it may only protect against the type of gluten cross-contamination you might experience at a restaurant.

There's lots more research to be done on this topic. But in the meantime, there are some steps you can take to help ensure your intestinal lining is as healthy as possible, regardless of whether you think you might have leaky gut:

Anecdotally, some people have been successful in reducing or eliminating the symptoms they attribute to leaky gut by following these approaches, even without firm evidence from medical studies to back them.


Jauregi-Miguel A et al. Alteration of tight junction gene expression in celiac disease. Journal of Pediatric Gastroenterology and Nutrition. 2014 Jun;58(6):762-7.

McCarville J et al. BL-7010 demonstrates specific binding to gliadin and reduces gluten-associated pathology in a chronic mouse model of gliadin sensitivity. PLOS One. 2014 Nov 3;9(11):e109972.

Smecuol E et al. Exploratory, randomized, double-blind, placebo-controlled study on the effects of Bifidobacterium infantis natren life start strain super strain in active celiac disease. Journal of Clinical Gastroenterology. 2013 Feb;47(2):139-47.

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