(Healthline) – The term “leaky gut” has gained a lot of attention in recent years.
Also known as increased intestinal permeability, it’s a condition in which gaps in your intestinal walls start to loosen. This allows larger substances, such as bacteria, toxins, and undigested food particles, to pass across the intestinal walls into your bloodstream.
Studies have associated increased intestinal permeability with several chronic and autoimmune diseases, including type 1 diabetes and celiac disease.
This article takes a close look at leaky gut and its causes. It also includes a list of foods that aid digestive health and a one-week sample meal plan.
What is leaky gut syndrome?
Leaky gut syndrome is a proposed condition caused by increased intestinal permeability.
The digestive system consists of many organs that collectively break down food, absorb nutrients and water, and remove waste products. Your intestinal lining acts as a barrier between your gut and bloodstream to prevent potentially harmful substances from entering your body (1Trusted Source, 2Trusted Source).
Nutrient and water absorption mostly 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.
Alternative health practitioners claim that leaky gut triggers widespread inflammation and stimulates an immune reaction, causing various health problems (3Trusted Source).
They believe leaky gut leads to various conditions, including autoimmune diseases, migraines, autism, food sensitivities, skin conditions, brain fog, and chronic fatigue.
Yet, there is little evidence to prove that leaky gut syndrome is a serious problem. As a result, mainstream physicians do not recognize it as a medical diagnosis.
Although increased intestinal permeability exists and occurs alongside many diseases, it’s not clear if it’s a symptom or underlying cause of chronic disease (4Trusted Source).
Leaky gut, or increased intestinal permeability, occurs when the tight junctions of your intestinal walls loosen. This may allow harmful substances, such as bacteria, toxins, and undigested food particles, to pass into your bloodstream.
What causes leaky gut syndrome?
The exact cause of leaky gut is a mystery.
However, increased intestinal permeability is well known and occurs alongside several chronic diseases, including celiac disease and type 1 diabetes (5).
Zonulin is a protein that regulates tight junctions. Research has shown that higher levels of this protein may loosen tight junctions and increase intestinal permeability (6Trusted Source, 7Trusted Source).
Two factors may stimulate higher zonulin levels in certain individuals — bacteria and gluten (8Trusted Source).
There is consistent evidence that gluten increases intestinal permeability in people with celiac disease (9Trusted Source, 10Trusted Source).
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 observed the same effect (10Trusted Source, 11Trusted Source, 12Trusted Source).
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 nonsteroidal anti-inflammatory drugs (NSAIDs), such as aspirin and ibuprofen, may increase intestinal permeability (13Trusted Source, 14Trusted Source, 15Trusted Source, 16Trusted Source).
Furthermore, low levels of healthy gut bacteria may have the same effect. This is called gut dysbiosis (17Trusted Source).
The exact cause of leaky gut remains a mystery, but certain proteins like zonulin and markers of inflammation provide some clues. Other potential causes include long-term NSAID use and an imbalance of gut bacteria known as gut dysbiosis.
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 (18Trusted Source).
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
A diet that promotes digestive health should focus on fibrous vegetables, fruits, fermented vegetables, cultured dairy products, healthy fats, and lean, unprocessed meats.
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 that are linked to many chronic diseases (19Trusted Source).
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
Avoiding processed junk foods, alcohol, sugary beverages, refined oils, and artificial sweeteners may aid the growth of healthy gut bacteria. Cutting out foods containing gluten or common stimulants of digestive symptoms may also help.
A sample menu for one week
Below is a healthy one-week sample menu for improving your digestive health.
It focuses on incorporating foods that promote the growth of healthy gut bacteria while removing foods that are notorious for causing uncomfortable digestive symptoms.
Some menu items contain sauerkraut, a type of fermented cabbage that is easy, simple, and inexpensive to prepare.
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: salmon, egg, and veggie frittata
Dinner: grilled lemon chicken salad with a side of sauerkraut
Breakfast: gluten-free oatmeal with 1/4 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-papaya chia pudding — 1/4 cup chia seeds, 1 cup unsweetened coconut milk, and 1/4 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
A healthy gut menu should be rich in fruits, vegetables, and lean protein. Fermented vegetables like sauerkraut or cultured dairy products like Greek yogurt are also excellent additions, as they’re a great source of healthy gut bacteria.
Other ways to improve your gut health
Although diet is key to improving gut health, there are plenty of other steps you can take.
Here are some more ways to improve your gut health:
Take a probiotic supplement. Probiotics contain beneficial bacteria that are naturally present in fermented foods. Taking a probiotic supplement, which you can find online, may improve gut health if you don’t get enough probiotics through your diet (20Trusted Source).
Reduce stress. Chronic stress has been shown to harm beneficial gut bacteria. Activities like meditation or yoga can help (21Trusted Source).
Avoid smoking. Cigarette smoke is a risk factor for several bowel conditions and may increase inflammation in the digestive tract. Quitting smoking can raise healthy bacteria numbers and reduce harmful gut bacteria (22Trusted Source).
Sleep more. Lack of sleep can cause a poor distribution of healthy gut bacteria, possibly resulting in increased intestinal permeability (23Trusted Source).
Limit alcohol intake. Research has shown that excessive alcohol intake may increase intestinal permeability by interacting with certain proteins (24Trusted Source, 25Trusted Source, 26Trusted Source).
If you think you have leaky gut syndrome, consider getting tested for celiac disease.
The two disorders can have overlapping symptoms.
Some people also find that diets like the Gut and Psychology Syndrome (GAPS) diet may ease leaky gut symptoms. However, this diet is incredibly restrictive, and no scientific studies support its health claims.
Aside from diet, try taking a probiotic supplement, reducing your stress levels, sleeping more, avoiding smoking, and limiting alcohol intake to improve your gut health.