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The gut serves as an important barrier to protect the body from bacteria and harmful substances present in the digestive tract.
Leaky gut occurs when this barrier becomes compromised and allows these substances to leak or pass from the intestine to parts of the body where they can cause health problems.
Many dietary factors can contribute to leaky gut while others can help prevent the condition.
This article explains the link between diet and leaky gut and provides a list of foods to eat and avoid as well as a 3-day sample leaky gut diet menu.
What is leaky gut?
The integrity of the intestinal barrier is crucial for gut and overall health.
This barrier is maintained by a series of proteins that form junctions between cells that line the intestines.
Dysfunction in these junctions causes leaky gut, or increased intestinal permeability, which allows harmful compounds such as inflammatory proteins, food antigens, and bacteria to pass from the intestines to the bloodstream.
Here these harmful compounds trigger an immune response and promote inflammation.
Historically, leaky gut — also known as leaky gut syndrome — was associated with alternative medicine, but evidence suggests a link between leaky gut and multiple conditions.
Conditions that are known to involve leaky gut, including (1):
- celiac disease
- inflammatory bowel disease
- rheumatoid arthritis
- eosinophilic esophagitis (EoE)
- irritable bowel syndrome
- small intestinal bacterial overgrowth (SIBO)
- fatty liver disease
It’s unlikely that leaky gut directly causes these conditions but it may overwhelm the body’s defenses and contribute to their development in susceptible individuals (2).
The standard test for leaky gut involves administering and measuring the amount of an undigestable sugar like mannitol that passes through the intestinal barrier and is excreted in the urine (3).
The more sugar that’s excreted in the urine, the more that was allowed to pass the intestinal barrier, suggesting increased intestinal permeability.
The symptoms of leaky gut tend to be nonspecific but may include:
- chronic diarrhea
- frequent illnesses
- brain fog
Diet and leaky gut
Microorganisms that reside in the intestines — collectively called the gut microbiota — play a key role in maintaining the integrity of the intestinal barrier.
The gut microbiota is largely shaped by diet, with some dietary patterns promoting a healthy gut microbiota and others promoting a dysfunction in the gut microbiota, known as dysbiosis.
For example, the Western or standard American diet (SDA) — which is rich in pre-packaged foods, refined grains, and sugar — is associated with dysbiosis and leaky gut (4).
In contrast, diets rich in fruits, vegetables, and whole grains promote a healthy gut microbiota and offer protection against leaky gut (6).
Foods to eat
Owing to the role the gut microbiota plays in maintaining the gut barrier integrity, eating foods that promote gut health is the best strategy for preventing and treating leaky gut.
Here are the best foods to eat for leaky gut:
Fruits and vegetables
Fruits and vegetables are high in fiber and rich sources of beneficial plant compounds called polyphenols.
Fiber nourishes the good gut bacteria, decreases gut inflammation, and promotes increased gut microbiota diversity (7).
Polyphenols enhance intestinal barrier function and offer protective effects against dysbiosis through their antioxidant and anti-inflammatory effects (8).
A study in older adults showed that those who consumed a polyphenol-rich diet consisting of foods like berries, pomegranate juice, apples, and green tea for eight weeks experienced significant improvements in intestinal permeability compared with those who followed a polyphenol-poor diet (9).
Aim to include a variety of fruits and vegetables in your diet, as each one offers its unique polyphenol profile.
Like fruits and vegetables, whole grains are also rich sources of fiber and polyphenols.
Gut bacteria ferment certain fibers from whole grains, beneficially altering the composition of the gut microbiota and improving the gut barrier function to reduce leaky (10).
Examples of whole grains include:
- brown rice
- whole-grain bread and pasta
Some whole grains contain gluten and FODMAPs and should be avoided by people who are allergic or intolerant to them.
Unsaturated fatty acids tend to have anti-inflammatory effects that decrease intestinal permeability and improve intestinal barrier function (11).
Omega-3 fatty acids like eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) have been shown particularly effective for improving leaky gut (11).
Fatty fish like salmon, mackerel, and tuna are among the best sources of omega-3 fatty acids, with nuts and seeds also being good sources.
Other sources of healthy fats include avocado, whole eggs, and extra virgin olive oil.
Healthy proteins are those that tend to be low in saturated fat.
Protein is crucial for immune function and protein needs tend to be higher in people with conditions associated with leaky gut (12).
Healthy sources of protein include:
- skinless poultry
- lean cuts of beef and pork
- fish and shellfish
- seeds and nuts
- milk, cottage cheese, and yogurt
Foods to avoid
Just as some foods can decrease gut permeability and strengthen the intestinal barrier, others can have the opposite effect.
Here are foods to avoid or limit that have been linked with signs of leaky gut:
Even a single alcohol binge episode has been shown to increase levels of inflammatory proteins and cause signs of leaky gut (16).
Saturated fats are a type of fat found primarily in animal products.
They’re also found in a variety of highly-processed foods, such as fried food, desserts, biscuits, microwave popcorn, chips, and other snack foods.
Saturated fats tend to be pro-inflammatory, meaning they promote inflammation in the body, which can promote gut dysbiosis and leaky gut (17).
As such, limit your consumption of foods rich in saturated fats, such as processed meats, snack foods, fried foods, and desserts.
The saturated fats naturally found in dairy products like milk, yogurt, and cheese haven’t been shown to be pro-inflammatory — and actually tend to be anti-inflammatory.
Refined grains and added sugars
Refined grains are highly processed and include foods like white flour, white rice, white bread, desserts, and some breakfast cereals.
Many of these foods also contain added sugars, which are added during the manufacturing process to enhance flavor or texture or extend shelf life.
Other examples of added sugars include sugar-sweetened drinks like soft drinks, sports drinks, and energy drinks, condiments like barbeque sauce and salad dressings, and sweets.
These foods lack dietary fiber and in excessive amounts, promote gut dysbiosis and increased intestinal permeability (17).
3-day sample leaky gut diet menu
Use this 3-day sample leaky gut diet menu to guide your food choices.
You may not be able to tolerate some of these foods due to intolerances or allergies.
- Breakfast: scrambled eggs and oatmeal topped with blueberries
- Lunch: Mediterranean grilled chicken salad
- Snack: cottage cheese with peach slices
- Dinner: baked salmon, roasted sweet potatoes, and sauteed green beans
Day 2 (vegan option)
- Breakfast: tofu scramble and oatmeal with berries
- Lunch: vegan salad tacos
- Snack: chia pudding with fruit
- Dinner: broccoli pasta salad
- Breakfast: overnight oats
- Lunch: grilled bruschetta chicken
- Snack: Greek yogurt and an apple
- Dinner: beef and broccoli with whole-grain rice
Supplements for leaky gut
A variety of supplements have been shown to benefit gut health and improve leaky gut.
Glutamine is an amino acid and the preferred source of fuel for cells in the intestines (18).
It’s considered a conditionally essential amino acid, meaning it’s only essential during times of illness and stress.
Supplementing with glutamine is thought to help repair and maintain the integrity of the intestinal barrier.
In one study, patients with irritable bowel syndrome with leaky gut who supplemented with 15 grams of glutamine daily for eight weeks experienced reductions in intestinal permeability (19).
Probiotics are beneficial bacteria that help with food digestion, inflammation, and immunity.
Prebiotics are fibers that help these bacteria grow and thrive.
Supplementing with a combination of probiotics and prebiotics — called synbiotics — may help improve leaky gut.
In one study, participants who supplemented with synbiotics in combination with a low-calorie diet for three months experienced improvements in microbial diversity and decreased intestinal permeability compared with those who only followed a low-calorie diet (20).
Probiotics, prebiotics, or synbiotics are generally safe for most people, but probiotics aren’t recommended for people with Crohn’s disease, and prebiotics may worsen symptoms in some people with irritable bowel syndrome since they contain FODMAPs (12).
Zinc is a mineral that supports immune health and metabolism.
Most people get enough zinc through their diets, but a zinc deficiency tends to be highly prevalent among people with inflammatory bowel disease and has been associated with a leaky gut.
Higher intakes of zinc have been associated with decreases in copper levels since zinc and copper compete with absorption (22).
As such, if you choose to supplement with doses above the tolerable upper limit for zinc of 40 mg per day, it may be best to do so under medical supervision (23).
Find zinc supplements online.
While classified as a vitamin, vitamin D is more of a hormone.
It plays a variety of roles related to bone health, muscle function, and immunity, but it also plays important roles in gut health.
Vitamin D supports the integrity of the intestinal barrier and helps control inflammation that can lead to leaky gut (24).
As such, a vitamin D deficiency — which is highly prevalent — has been linked with gut dysbiosis and inflammation (25).
You can make vitamin D when your skin is exposed to sunlight, but not everyone lives in an area that allows adequate exposure to sunlight year-round.
You can also get vitamin D from your diet but few foods are naturally good sources of vitamin D.
These factors make vitamin D supplements an inexpensive and more effective way to maintain healthy levels for most people.
A vitamin D supplement that provides 1,000–2,000 IUs (25–50 mcg) is a good place to start.
Shop for vitamin D online.
The bottom line
Leaky gut refers to a dysfunction in the intestinal barrier.
Several conditions are linked with leaky gut, including irritable bowel syndrome, inflammatory bowel disease, fatty liver disease, and SIBO, among others.
A diet rich in fruits, vegetables, whole grains, and healthy proteins and fat provides fiber and other important nutrients that support gut health and help protect against leaky gut.
Avoid or limit alcohol, saturated fats, and as well as refined grains and added sugars as these items can compromise the integrity of the intestinal barrier and promote leaky gut.
In addition to diet, supplementing with glutamine, synbiotics, zinc, and vitamin D have also shown benefits for improving leaky gut in people with certain conditions.