Leaky gut syndrome is a condition that affects your digestive system.
The digestive system consists of many organs that collectively break down food, absorb nutrients and water and remove waste products. It also acts as a barrier between your gut and bloodstream to prevent harmful substances from entering your body (1, 2).
Most nutrient and water absorption occurs in your intestines. Your intestines have tight junctions, or small gaps, that allow nutrients and water to pass into your bloodstream.
How easily substances pass across the intestinal walls is known as intestinal permeability.
In leaky gut syndrome, these tight junctions loosen, potentially allowing harmful substances like bacteria, toxins and undigested food particles to enter your bloodstream.
his is thought to trigger widespread inflammation and stimulate an immune reaction (3).
Yet, there is little evidence to prove that leaky gut syndrome is a serious problem. As a result, it’s not recognized as a medical diagnosis by mainstream physicians.
On the other hand, many alternative practitioners believe leaky gut syndrome is linked to various conditions, including autoimmune diseases, migraines, autism, food sensitivities, skin conditions, brain fog and chronic fatigue.
Increased intestinal permeability exists and occurs alongside many diseases. However, it’s not clear if it’s a symptom or underlying cause of chronic disease (4).
What Causes Leaky Gut Syndrome?
The exact cause of leaky gut syndrome is a mystery.
However, increased intestinal permeability is well known and occurs alongside several chronic diseases, including celiac disease and type 1 diabetes (5).
Two factors may stimulate higher zonulin levels — bacteria and gluten (8).
However, research in healthy adults and those with non-celiac gluten sensitivity shows mixed results. While test-tube studies have found that gluten can increase intestinal permeability, human-based studies have not had the same effect (10, 11, 12).
Aside from zonulin, other factors can also increase intestinal permeability.
Research shows that higher levels of inflammatory mediators, such as tumor necrosis factor (TNF) and interleukin 13 (IL-13), or the long-term use of non-steroidal anti-inflammatory drugs (NSAIDS), such as aspirin and ibuprofen, may increase intestinal permeability (13, 14, 15, 16).
Furthermore, low levels of healthy gut bacteria may have the same effect. This is called gut dysbiosis (17).
Foods to Eat
As leaky gut syndrome isn’t an official medical diagnosis, there is no recommended treatment.
Yet, you can do plenty of things to improve your digestive health.
One is to eat a diet rich in foods that aid the growth of beneficial gut bacteria. An unhealthy collection of gut bacteria has been linked to poor health outcomes, including chronic inflammation, cancers, heart disease and type 2 diabetes (18).
The following foods are great options for improving your digestive health:
Vegetables: Broccoli, Brussels sprouts, cabbage, arugula, carrots, kale, eggplant, beetroot, Swiss chard, spinach, ginger, mushrooms and zucchini.
Roots and tubers: Potatoes, sweet potatoes, yams, carrots, squash and turnips.
Fermented vegetables: Kimchi, sauerkraut, tempeh and miso.
Fruit: Coconut, grapes, bananas, blueberries, raspberries, strawberries, kiwi, pineapple, oranges, mandarin, lemon, limes, passionfruit and papaya.
Sprouted seeds: Chia seeds, flax seeds, sunflower seeds and more.
Gluten-free grains: Buckwheat, amaranth, rice (brown and white), sorghum, teff and gluten-free oats.
Healthy fats: Avocado, avocado oil, coconut oil and extra virgin olive oil.
Fish: Salmon, tuna, herring and other omega-3-rich fish.
Meats and eggs: Lean cuts of chicken, beef, lamb, turkey and eggs.
Herbs and spices: All herbs and spices.
Cultured dairy products: Kefir, yogurt, Greek yogurt and traditional buttermilk.
Beverages: Bone broth, teas, coconut milk, nut milk, water and kombucha.
Nuts: Raw nuts including peanuts, almonds and nut-based products, such as nut milks.
Foods to Avoid
Avoiding certain foods is equally important for improving your gut health.
Some foods have been shown to cause inflammation in your body, which may promote the growth of unhealthy gut bacteria linked to many chronic diseases (19).
The following list contains foods that may harm healthy gut bacteria, as well as some that are believed to trigger digestive symptoms, such as bloating, constipation and diarrhea:
Wheat-based products: Bread, pasta, cereals, wheat flour, couscous, etc.
Gluten-containing grains: Barley, rye, bulgur, seitan, triticale and oats.
Processed meats: Cold cuts, deli meats, bacon, hot dogs, etc.
Baked goods: Cakes, muffins, cookies, pies, pastries and pizza.
Snack foods: Crackers, muesli bars, popcorn, pretzels, etc.
Junk food: Fast foods, potato chips, sugary cereals, candy bars, etc.
Dairy products: Milk, cheeses and ice cream.
Refined oils: Canola, sunflower, soybean and safflower oils.
Artificial sweeteners: Aspartame, sucralose and saccharin.
Sauces: Salad dressings, as well as soy, teriyaki and hoisin sauce.
Beverages: Alcohol, carbonated beverages and other sugary drinks.
Breakfast: Blueberry, banana and Greek yogurt smoothie.
Lunch: Mixed green salad with sliced hard-boiled eggs.
Dinner: Beef and broccoli stir-fry with zucchini noodles and sauerkraut.
Breakfast: Omelet with veggies of your choice.
Lunch: Leftovers from Monday’s dinner.
Dinner: Seared salmon served with a fresh garden salad.
Breakfast: Blueberry, Greek yogurt and unsweetened almond milk smoothie.
Lunch: Homemade salmon, egg and veggie frittata.
Dinner: Grilled lemon chicken salad with a side of sauerkraut.
Breakfast: Gluten-free oatmeal with one-fourth cup raspberries.
Lunch: Leftovers from Wednesday’s dinner.
Dinner: Broiled steak with Brussels sprouts and sweet potatoes.
Breakfast: Kale, pineapple and unsweetened almond milk smoothie.
Lunch: Beet, carrot, kale, spinach and brown rice salad.
Dinner: Baked chicken served with roasted carrots, beans and broccoli.
Breakfast: Coconut and papaya chia pudding — one-fourth cup chia seeds, one cup unsweetened coconut milk and one-fourth cup diced papaya.
Lunch: Chicken salad with olive oil.
Dinner: Roasted tempeh with Brussels sprouts and brown rice.
Breakfast: Mushroom, spinach and zucchini frittata.
Lunch: Sweet potato halves stuffed with spinach, turkey and fresh cranberries.
Dinner: Grilled chicken wings with a side of fresh spinach and sauerkraut.