The terms "leaky gut" and "leaky gut syndrome" (sometimes called intestinal permeability) are being tossed around a lot more lately by integrative and functional nutrition experts, especially in regards to patients who suffer from painful digestive conditions like IBS or celiac disease. But even so, there's still a lot of confusion as to what a leaky gut actually is and how to best treat it.
The good news: More evidence is supporting the idea that you can heal a leaky gut and ease your digestive woes by changing your diet and lifestyle. Here, learn more about leaky gut and its potential causes and what foods may help (or harm) your healing process.
What is leaky gut syndrome (or intestinal permeability)?
At the most basic level, a leaky gut means your intestines aren't as secure as they should be.
Here's a quick biology lesson: The walls of the intestines are supposed to be permeable to a degree. This is how the nutrients from the food we eat make it into the body while parts of food we can't use continue through the intestines and eventually leave as waste. Ideally, the barrier of the intestines is such that only tiny nutrients can be absorbed into the bloodstream while things like toxins and microbes stay on track to be excreted.
The problem occurs when the intestinal tight junctions—spaces between the cells that regulate what enters the bloodstream—are broken apart (which can happen for a variety of reasons). This allows toxins, microbes, and undigested food particles to "leak" into the bloodstream, where the immune system often marks them as pathogens and attacks. This is considered leaky gut, or increased intestinal permeability.
Increased intestinal permeability is known to play a role in some gastrointestinal conditions, including celiac disease, Crohn's disease, and irritable bowel syndrome (IBS). While scientists are in agreement that increased intestinal permeability is related to these gastrointestinal issues, it's not clear whether the increased permeability is the cause or a side effect of them.
Some studies link leaky gut with autoimmune diseases such as arthritis and thyroid disorders, too. "Mainstream medicine once considered leaky gut syndrome a fake diagnosis given by alternative quacks. But today, research is confirming that a leaky gut, or increased intestinal permeability, is indeed a major factor in chronic and autoimmune diseases," Will Cole, D.C., IFMCP, functional nutrition expert, told mbg.
What causes a leaky gut?
So what causes increased intestinal permeability? A 2013 study pointed the finger at zonulin, a human protein that researchers described as "the only known...modulator of intercellular [tight junctions] described so far." In layman's terms: When zonulin is released, the tight junctions of the intestines can break apart.
Bacteria and gluten have been shown to trigger zonulin release in the small intestine, which is key to understanding why many functional nutrition experts recommend treating the condition with dietary changes, like a gluten-free diet.
There may be other factors that contribute to a leaky gut as well, including medications like NSAID pain relievers and antibiotics, stress, and environmental toxins.
Foods to avoid when you have a leaky gut.
While gluten is often called out as the main cause of a leaky gut, experts also point to the consumption of other pro-inflammatory foods. Vincent Pedre, M.D., gut health expert and medical director of Pedre Integrative Health, recommends eliminating the following foods from your diet if you suspect you have a leaky gut:
Gluten: Because gluten is linked to the release of zonulin, it tops most doctors' lists of leaky-gut-causing foods. Common sources of gluten include pastas, noodles, breads, pastries, cereal, granola, and beer (or any malt beverage, really).
Sugar: This includes not just refined sugars like high-fructose corn syrup but also seemingly "healthy" sweeteners like monk fruit and coconut sugar. Sugar wreaks havoc in your gut, and research shows it can feed bad gut bacteria. Alcoholic beverages also break down as sugars, so scale back on the vino.
Dairy products: This includes milk, yogurt, ice cream, and cheese. Specifically, there are two proteins in dairy that many people struggle to digest—casein and whey. Additionally, many people don't have enough lactase to properly break down the lactose in milk, which can lead to gastrointestinal distress and potential gut damage.
Soy products: Soy and its derivatives can be found in everything from tofu to edamame, protein bars, and even some nutritional supplements. Soy is often a genetically modified food as well, which may trigger gut flora imbalances, and many experts recommend avoiding all GM foods if you have a leaky gut.
Corn: More than 90 percent of the corn grown in the United States is reportedly genetically modified. It's also a food to which many people (especially those with leaky guts) can develop a sensitivity. The effects of a corn sensitivity are similar to those of a gluten sensitivity. Like gluten and soy, corn is present in many packaged foods, so it's important to read labels carefully.
Lectins and phytates: These compounds, often called anti-nutrients, are found in all gluten-containing grains. Lectins are also found in beans, corn, and the nightshade vegetables like tomatoes, eggplant, peppers, and potatoes. Lectins bind to the cells lining your intestines, disrupting the tight junctions between the intestinal cells, contributing to leaky gut, while phytates interfere with the absorption of important minerals.
Foods to eat when you have a leaky gut.
Now that you know what not to eat, you might be wondering what's left. "Focus on clean ingredients with easy-to-digest foods that are low in fructose and sugar and devoid of any substances, including sugar alcohols and pesticides, that are hard on the gut," Dr. Pedre told mbg. Want more specifics? Below are the basic components of a gut-friendly diet:
(Important note: If you suspect that your leaky gut is caused by IBS, or if you don't thrive when eating the foods below, you may need a stricter approach called a low-FODMAP diet.)
Healthy fats: Go for quality fat sources like nuts, seeds, avocado, olive oil, and coconut oil. Skip ultra-refined vegetable oils like corn and soybean, which can promote inflammation.
High-fiber, low-glycemic carbs: These include nonstarchy vegetables. Think leafy greens and cruciferous vegetables such as arugula, broccoli, Brussels sprouts, cabbage, cauliflower, and collard greens. These are a great source of prebiotic fiber, which can help feed the healthy probiotic bacteria in your gut, which are essential to gut health.
Slow carbs: Think starchy vegetables such as sweet potatoes and butternut squash; fiber-rich, low-sugar fruits like apples and berries; and minimally processed, fiber-rich grains like rolled oats instead of breads and refined grains. These are less likely to contain anti-nutrients like lectins and phytates that can aggravate the gut.
Hypoallergenic proteins: These include pea, rice, hemp, chia. A leaky gut makes people more prone to food allergies and sensitivities, meaning it's a good general practice to go hypoallergenic when possible.
Clean and lean proteins: Compared to their conventional counterparts, free-range poultry, wild-caught fish, and grass-fed meats contain healthier concentrations of omega-3 fats, which are anti-inflammatory.
Bone broth (or collagen): The gelatin in bone broth protects and heals the mucosal lining of the digestive tract and helps aid in the digestion of nutrients. Some research suggests collagen peptides may have a similar benefit. Bone broth is also a rich source of glutamine, an amino acid that's a preferred source of energy for the cells of the small bowel and other immune cells and that has been shown to reduce intestinal permeability. Want a vegan alternative? Galangal broth, a traditional Chinese medicine remedy, may also help heal a leaky gut.
Fermented foods: Foods like kimchi, unpasteurized sauerkraut, and lacto-fermented pickles are all rich sources of probiotics that help keep your immune system strong, fend off pathogens, and protect the gut lining.
A sample day on the leaky gut diet.
Here are some meal ideas to get you started on a leaky gut diet, but feel free to mix and match with the foods above:
Breakfast: Skip the bagel and processed breakfast cereal and opt for a couple of scrambled eggs with a side of sautéed kale (pro tip: Cooked veggies are gentler on the gut and may be smarter than raw when initially starting a leaky gut diet). Want something sweet? Go for a bowl of oatmeal with almond milk, berries, and walnuts.
Lunch: Ditch the sandwich for a salad with lentils and lean protein for sustained energy and a good dose of prebiotic fiber. Add some kimchi or sauerkraut for a probiotic boost. Salads not your thing? Scoop some tuna or chicken salad (made with an avocado-oil-based mayo) into romaine lettuce and eat it like a taco! Who needs bread?!
Snack: Go for some carrot slices with hummus, apple slices with almond butter, or crunchy roasted chickpeas. The possibilities are endless, but leaky-gut-friendly snacks should include some gut-friendly fiber along with a bit of fat and protein to promote stable blood sugar.
Dinner: Think of this simple formula: Quality protein source + nonstarchy veggie + starchy veggie (optional) + healthy fat. Pan-seared salmon and roasted sweet potato and Brussels sprouts cooked in olive oil would fit the bill. Another option? Zucchini noodles with pesto, sun-dried tomatoes, and grilled chicken.
Habits that complement a leaky gut diet.
Changing your diet may not completely heal your leaky gut. So, in addition to loading up on gut-friendly foods (and nixing the bad stuff), consider making the following tweaks:
- Pop a probiotic supplement: Good gut bacteria, which are crucial in preventing leaky gut, can become depleted or disrupted by a number of things (poor diet, antibiotics, steroids, antacids, etc.), and fermented foods may not deliver the amount you need. So, taking a highly concentrated probiotic (25 to 100 billion units) daily may help you regain a healthy balance of bacteria in your gut.
- Reduce your use of NSAIDs: This class of anti-inflammatory pain relievers is notoriously harsh on the stomach, and research suggests that taking them too frequently may increase risk of intestinal permeability. So, for minor aches and pains that don't require serious intervention, consider popping a gentle, natural anti-inflammatory like turmeric.
- Find healthy ways to de-stress: If you've heard of the gut-brain axis, you know that our thoughts can have a direct impact on things like digestion and overall gut health. So, it's no surprise that chronic stress has been associated with increased intestinal permeability, or leaky gut. So, try to do something that helps you chill on a regular basis. Yoga, meditation, progressive muscle relaxation, deep breathing, and body scanning are all great options.
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