What Is Leaky Gut?

By: Jessica Migala  |  July/August 2016
Here's what you need to know about this hot health topic including the symptoms and diets that may help.
Is leaky gut real? It's a debate that's been floating around the internet. Our answer: in a word—yes.
So what is leaky gut? The medical name for leaky gut is "intestinal permeability" and it's neither disease nor symptom—intestinal permeability is a natural biological function. Lining your intestines is a barrier of cells; between each cell is a tight junction that keeps bad things (like toxins and bad bacteria) out of your body and allows good things (nutrients) in.
The issue is that this natural permeability can go awry if the barrier becomes faulty. In genetically susceptible people, leaky gut can be triggered by gut bacteria disruptions from poor diet, some medications or gluten. Importantly, experts don't agree on what is and isn't a trigger.
But once permeability is disrupted, the bad guys "leak" into your bloodstream and trigger inflammation, causing other health issues. So then: when intestinal permeability goes wrong, what problems does it start?
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Leaky Gut Symptoms

There's strong evidence that leaky gut can cause food allergies, inflammatory bowel disease (IBD) and celiac disease, says Alessio Fasano, M.D., chief of the division of pediatric gastroenterology and nutrition at Massachusetts General Hospital and director of the Center for Celiac Research. There's good evidence leaky gut may lead to type 1 diabetes or multiple sclerosis, and more limited research links it to nonalcoholic fatty liver disease and type 2 diabetes. Other experts like Amy Myers, M.D., author of The Autoimmune Solution, believe leaky gut contributes to a wider host of ills, such as seasonal allergies, depression and eczema.
"Leaky gut has become one of those things that people blame all their health issues on," says Purna Kashyap, M.B.B.S., assistant professor of medicine in the department of gastroenterology and hepatology at Mayo Clinic. "Sorry to say, it won't be the answer to everyone's problems or mysterious symptoms." While research does support that certain conditions may be caused by leaky gut, unless you've been diagnosed with one of these, it's hard to say for sure if your gut has sprung a leak.
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Leaky Gut Diets

Google "leaky gut" and you'll find a host of diets that are said to be a sure-fire cure. But how you fix leaky gut depends on your condition. "Unless you know what you are treating, it's hard to tell someone to go on a dietary regime to improve leaky gut," says Kashyap. These four diets draw a lot of attention for helping leaky gut. Here's how they really stack up.
Low FODMAP Diet
If you have IBD or irritable bowel syndrome (conditions linked to leaky gut), you may have a hard time digesting "FODMAPs": fermentable oligo-, di- and monosaccharides and polyols. Some high-FODMAP foods include beans, apples and mushrooms. Low-FODMAP foods include low-lactose dairy (hard cheeses and Greek yogurt), bananas, gluten-free grains and cucumbers. After some time you can slowly reintroduce high-FODMAP foods to figure out what triggers your symptoms. But if you don't have IBD or IBS, this isn't a generalized cure for leaky gut.
Paleo Diet
This "caveman" style of eating favors produce, pasture-raised meats, wild-caught fish, nuts and seeds, and nixes dairy, grains, processed food and refined sugar. Swapping junk food for fresh fare is a good move for anyone, but there's no scientific evidence that a Paleo diet addresses leaky gut. Check out other pros and cons of the paleo diet.
The GAPS Diet
The Gut and Psychology Syndrome (GAPS) Diet advocates eliminating a long list of "difficult to digest and damaging" foods like grains and starches, most dairy and processed sugars, and adds in bone broth and probiotic-rich foods. This diet claims to cure leaky gut plus treat conditions from depression to ADHD. It's one of the most hyped diets for leaky gut, but there's no supporting research behind it.
Gluten-Free
If you have celiac disease or gluten sensitivity, you need to skip gluten (found in wheat, barley and rye) to stop damage to the small intestine. But there's no reason for people without these conditions to avoid gluten. For more about this diet, get the facts from Unraveling the Gluten-Free Trend.
Bottom line: When it comes to any of these diets: when eating for leaky gut, it's all about context, meaning low-FODMAP may help IBD and gluten-free is necessary for celiac disease. Work with a gastroenterologist to identify ways to treat your symptoms, which may include dietary changes, but be aware: there is no one ideal diet for everyone. For most, Kashyap says, "A balanced diet should be as good or better as one of the dietary fads."
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Leaky Gut: Myth or Fact?

There are many rumors floating around about leaky gut (thanks, Internet...), so let's clear up some of the confusion.
Gluten causes leaky gut.
Fact. There's a component in gluten (a protein in wheat, barley, rye and related grains) that increases intestinal permeability, but for most of us, it's no big deal. "Gluten does this to everyone, but the vast majority aren't hurt by it," explains Fasano. "Their gut leaks for a short period of time and closes without harm." Only in genetically prone people (like those with celiac) does the leak persist and the gluten triggers an inflammatory response. If you experience symptoms from eating gluten, check out these gluten-free recipes.
You should get tested for leaky gut.
Myth. The tests to diagnose leaky gut may be a waste of time and money. "In my practice," says ­Myers, "if you have an autoimmune disease, I assume you have leaky gut. It doesn't change how I treat my patients." And Fasano points out that these tests have limited accuracy. Even more reason to pass.
Toxins are to blame.
Maybe. "Toxins can disrupt the balance of good bacteria, opening the door for bad bacteria to take over and damage the gut lining," says Myers. But take note: experts don't agree on what factors lead to leaky gut. Environmental triggers may include mercury and air pollution. And certain food additives like emulsifiers (found on food labels as lecithin or polyglycerol esters), as well as too much salt and sugar, may contribute to leaky gut—again, reasons to avoid heavily processed fare. Preliminary research implicates NSAIDs (like ibuprofen), but only for a limited time—once you stop, your gut repairs itself—so occasional use is fine. Proton pump inhibitors for acid reflux and antibiotics may also be culprits.
Go with your gut! Check out more ways to give your gut a boost:
5 Ways to Improve Your Gut Flora
Top Fiber-Rich Foods for Good Gut Bacteria
7 Must-Eat Healthy Fermented Foods