Leaky Gut Diet: Which Diet Best Heals Your Gut?

By Amy Burkhart MD, RD

A leaky gut has been linked to chronic disease and inflammation, negatively impacting your overall health. Information regarding leaky gut and ideal treatments is controversial and confusing. How do you decide which treatment path to follow? Diet is one part of most treatment options. But what is the best leaky gut diet? Before we answer that however, let’s do a quick recap of what a leaky gut is and what are the symptoms of a leaky gut.

A healthy gut lining absorbs what we need

The “gut” is another term used to describe the digestive system. It includes everything from the mouth to the intestines and other parts of our body involved in digestion – like the gallbladder and pancreas.

When the gut is healthy, the lining of the gut acts as a guard, who minds the “doors” deciding what we absorb or don’t. Our gut needs to be somewhat “leaky” and allow nutrients to be utilized. That is how we absorb our food.  But, when the doors are open too long, unwanted guests pass through, and problems arise.

When the gut barrier breaks down, the gut becomes *“leaky.” The barrier is weakened by things such as bacteria and toxins that sneak in and cause chaos. Those doors that were shut by the guard are now open. What enters the body is no longer well-regulated and is seen as foreign – triggering the immune system to cause inflammation.

Chronic inflammation raises our risk of autoimmune diseases, IBS, chronic fatigue, and others. (1, 2, 3, 4).

*The medical terms for “leaky gut” are “increased permeability” or “more permeable.”

Symptoms of leaky gut can be non-specific

• Diarrhea
• Constipation
• Bloating
• Fatigue
• Joint pain
• Headaches
• “Brain fog”-trouble concentrating
• Vitamin deficiencies
• Rashes including eczema
• Acne
• Muscle pain/knots “fibromyalgia” type-symptoms

Symptoms of leaky gut are vague and can be seen with many conditions. A thorough medical history and evaluation are needed to distinguish symptoms of leaky gut from other conditions.

Changes in gut permeability are now validated by research

The existence of a leaky gut used to be controversial. That all changed with the discovery of a molecule called zonulin.

In 2000, Dr. Alessio Fasano and his team discovered zonulin, a protein our body makes that opens and closes those “doors” in our gut called tight junctions (5). His research was initially done on celiac disease patients, but its significance reaches far beyond celiac disease and gluten-related disorders. Zonulin has become a marker for intestinal permeability or “leakiness.”

As research has unfolded since 2001, we now know that a leaky gut correlates with inflammation and is seen in many other diseases, such as IBS, depression, inflammatory bowel disease, and autoimmune diseases (6). The discovery of zonulin and the explosion of interest in gut health, leaky gut, and the microbiome are being investigated as significant, modifiable risk factors in our long-term health (7, 8).

It must be noted that the topic of leaky gut is still not completely free of controversy. There is currently no universally accepted way to measure gut permeability. This means the diagnosis is made based on a person’s symptoms. And the symptoms of leaky gut are nonspecific. This makes diagnosing leaky gut difficult.

There are valid methods to study permeability, and commercial labs have created tests claiming to measure it. Still, the best way to measure gut permeability has not been determined.

How the gut’s permeability correlates with leaky gut symptoms and how to best treat it, is still not studied in humans. Leaky gut ymptoms vary from person to person, and multiple factors are most likely at play. And finally, as of yet, there is no research to say which interventions decrease the leakiness of the gut, decrease leaky gut symptoms, and potentially alter disease (9).

All this being said, there is no debate that inflammation is harmful, and decreasing inflammation will only be of benefit.

 Some things that cause your gut to be leakier include:

• Certain medications such as NSAIDs, Proton Pump Inhibitors
• Stress can worsen leaky gut symptoms
• Diet triggers: processed foods, sugar, gluten, alcohol, high-fat diet
• Changes in the microbiome, for example, due to illness or antibiotic use (11)
• A stomach infection such as gastroenteritis
• Excessive exercise (endurance athletes) (12)
• Low vitamin D (13)
• Food additives (e.g., carboxymethylcellulose, polysorbate-80, and others)
• Smoking
• Obesity
• Sugar
• Not enough fiber in your diet (14)

Remember, many factors influence our gut health (10).

Decreasing inflammation is the cornerstone of treatment

Inflammation makes the gut leakier (15). Because further research is needed to determine the best way to heal a leaky gut – decreasing inflammation is currently the cornerstone of leaky gut treatment.

From an integrative medicine perspective, treating a leaky gut incorporates many areas of a person’s life, such as diet, sleep, exercise, stress, and mental health. We approach all of these aspects to lower inflammation as much as possible.

The primary focus of this article is the dietary component of leaky gut treatment. Our nutritional choices influence how permeable, or “leaky,” our gut is (16). This means the foods you eat – today, tomorrow, and always – matter.

Chronic inflammation increases your risk of illnesses like autoimmune disease, anxiety, and depression. Taking steps today to make an anti-inflammatory diet and lifestyle choices will improve your odds of a future of optimal health.

Listed in alphabetical order, not the order of importance or recommendation.

The following are diets aimed at treating health and digestive problems. Many are also used by people to  “heal their leaky gut.”  Some have more research to back them than others.

AIP stands for Autoimmune protocol. It focuses on decreasing inflammation, the root of autoimmune diseases.

It eliminates:

• All dairy, including raw
• Eggs
• Legumes: beans, peanuts, hummus, etc
• Refined sugars
• Processed foods
• Industrial seed oils such as vegetable or canola oil
• Grains
• Nuts and seeds
• Chocolate
• Nightshade vegetables (tomatoes, peppers, potatoes, etc.)
• Alternative sweeteners
• Gums (xanthan, guar), food thickeners, and emulsifiers

The foods allowed are:

• Lean meats and liver
• Fermented foods
• High-quality seafood
• Vegetables except for nightshades (tomatoes, potatoes, peppers, eggplant)
• Fruit (in small amounts)
• Fats: olive oil, coconut oil, avocado oil

The goal of the AIP diet is to calm the immune system. The AIP diet has been used to intervene in several disease states, including inflammatory bowel disease (17).

While the theory behind why an AIP diet may help repair leaky gut is sound, it is very restrictive, and there are no research studies to back that claim up.

This diet has been shown to decrease inflammation.

The anti-inflammatory diet emphasizes fresh food, healthy oils and fats, low sugar, more fish than meat, and abundant fruits and vegetables. In addition to being a healthy eating plan, it is relatively easy to stick to in the long term.

Its direct effect on gut permeability has not been studied, but the diet includes foods that decrease inflammation (18).

This diet is best done under the supervision of a healthcare provider

An elemental diet provides nutrition components like protein, fat, and carbohydrates that are already broken down. The food is pre-digested, so your body doesn’t have to do the work if it isn’t able to. It is a way to give your digestive system a break.

It is most commonly used for people with chronic digestive problems under a healthcare provider’s supervision. It is usually purchased but can be homemade. It is a liquid or a powder that is mixed with water.

An elemental supplement can be consumed by the person or given through a feeding tube for severe cases where adequate nutrition can not be taken by mouth. It may be used for people with conditions such as Ulcerative Colitis, Crohn’s, or SIBO: Small intestinal bacterial overgrowth.

The elemental diet has been shown to improve a leaky gut (19, 20). 

Testing for celiac disease should be done before starting a gluten-free diet.

A gluten-free diet eliminates all food sources that contain wheat, barley, rye (and oats if they are not certified gluten-free). It is the only treatment currently available for celiac disease. It is also used by people who are gluten intolerant (also called gluten sensitivity). 

Research has linked gluten to trigger a leaky gut in people with celiac disease (21). Research has not yet proven that gluten triggers leaky gut in all people, although the internet may tell you differently (22).

Studies show that gluten increases permeability in people with celiac disease and gluten intolerance (23). A low-gluten diet has been shown to lower inflammation (24).

Intermittent fasting has many benefits but is not fit for everyone.

The recent darling of the dietary world is intermittent fasting. There are several types of intermittent fasting programs, of which the most popular is the 16:8 plan. Intermittent fasting is not recommended for everyone.

The ability of intermittent fasting to lower inflammation has been proven (25). More recent research has shown that alternate-day fasting and time-restricted fasting methods appear to improve gut permeability. This means they make the gut less leaky.

A keto diet was first used to treat seizures.

A ketogenic diet – or keto – is an eating plan that is very high in fat and low in carbohydrates and protein. The preferred fuel for our brain and body cells is glucose, a kind of sugar. Our body makes ketones a substitute fuel if we don’t have enough glucose available because of a low-carb diet.

Ketones are then used for energy, but they also suppress hunger. Going into ketosis is a survival mechanism that allows us to stay alive during food shortages.

The ketogenic diet was first investigated as an intervention for those with epilepsy or seizure disorder. Although currently quite popular, it is very restrictive and difficult to follow long-term (26).

A ketogenic diet influences the kinds of bacteria that thrive in our gut and may reduce inflammation (27, 28). There are no known studies linking keto and gut permeability directly just yet.

The low FODMAP diet is used to treat IBS.

F-O-D-M-A-P is an acronym for a group of carbohydrates that can cause diarrhea, stomach pain, and other symptoms in some people.

FODMAPS are found naturally in a wide range of foods, even healthy foods like onions, apples, and garlic. It is hard to predict which foods contain FODMAPS (31) without help or guidance from a healthcare provider. Yes, there is also an app for that.

So far, most of the research on a low FODMAP diet focuses on helping symptoms such as diarrhea and gas. One study did show that a  low FODMAP diet can improve gut function and reduce leaky gut (32). In part, this may be due to which bacteria are thriving in the gut (33).

The diet helps many people with IBS, and further research is warranted to look at the effect of the diet directly on the gut lining (34).

The Mediterranean diet is easy to follow for most people

The Mediterranean diet is a specific anti-inflammatory diet based on a high intake of whole fruits and veggies, olive oil, and a low intake of sweets, meat, and alcohol. The focus is on fish and beans and minimal red meat for protein.

The Mediterranean eating pattern is protective against many diseases, including cancer and Alzheimer’s. It may also help prevent and treat IBS symptoms. It’s relatively easy to follow. Fewer foods are eliminated, and many cookbooks and blogs have recipe and menu ideas.

Studies have shown that the more closely a person follows the Mediterranean eating pattern, the fewer IBS symptoms they have. (35). The Mediterranean diet can lower inflammation (36). Few studies are looking specifically at the Mediterranean diet and leaky gut.

There are many types of paleo diets.

Generally, a paleo diet is focused on eating “like a caveman,” i.e., how humans ate before organized farming and industrialization. It includes lean meats, fruits, veggies, and nuts while excluding grains, legumes, and processed foods with additives (37).

Most Paleo diets eliminate:

• Dairy (some versions permit it)
• Legumes: beans, peanuts, hummus, etc
• Refined sugars
• Processed foods
• Industrial seed oils such as vegetable or canola oil
• Grains

The foods permitted are:

• Meat and fish
• Eggs
• Nuts and seeds
• Fruits and vegetables (no corn)
• Fats: coconut, olive oil, avocado, lard, ghee
• Minimally processed sweeteners: raw honey, maple syrup, coconut sugar, raw stevia

Some paleo-style bloggers and cookbook authors are more liberal with their definition of a paleo diet. Many include recipes that use a fair amount of added sugars, claiming to be healthier since they’re less processed. Our bodies cannot distinguish between different kinds of added sugar very well. What is essential is not overeating added sugar, no matter the form. Sugar causes inflammation. The Paleo diet eliminates many inflammatory foods and has been shown to lower inflammation. (38, 39). No studies are looking directly at gut permeability and the paleo diet.

The SCD diet lowers inflammation but is challenging long-term

The Specific Carbohydrate Diet (SCD) has been around for almost 100 years. A physician initially developed it to help her child with celiac disease. Today it is used for many conditions, including inflammatory bowel disease (40).

Despite its name, the diet is not a low-carbohydrate diet. It focuses on eating simple carbohydrates that can be easily absorbed. It eliminates all grains, milk (except for hard cheese and yogurt), and sugar, except for honey. There is an overlap with the low FODMAP diet (41).

Research demonstrates an improvement in IBS symptoms with the SCD diet, but not research looking specifically at gut permeability. It has been shown to lower inflammation (42).

The Whole30 is a specific clean-eating program designed to improve your health, starting with the gut.

The program eliminates added sugar, additives, grains, alcohol, dairy, and legumes for 30 days. After 30 days, you try foods one at a time to see if you feel good after eating them (43). The ultimate goal is to continue eating nutrient-rich, unprocessed foods and avoid problematic foods for you.

There are no specific research studies on this eating plan, but it is based on a familiar nutrition principle – the elimination diet. Remove the most likely causes of symptoms to see if you feel better. Nourish your body, especially your gut, with whole foods free of additives and full of fiber, vitamins, and minerals for 30 days. Reintroduce the eliminated foods one at a time and see if you feel worse. Because this is so popular, many cookbooks, Whole30-approved brands, and blogs support your journey if you’re interested in trying it.

Even though there are no studies on this diet, it does eliminate processed foods, alcohol, and sugar, which would presumably decrease inflammation.

Lifestyle changes to help you heal and feel great

1. Decrease stress; stress can cause unwanted changes in the gut microbiome
2. Exercise 30-60  minutes daily; exercise has a positive effect on the gut and the microbiome
3. Sleep 7-9 hours a night; sleep has a significant effect on the microbiome
4. If possible, avoid medications that worsen leaky gut
5. Treat underlying medical conditions
6. Maintain a healthy weight; obesity is linked to inflammation in the gut
7. Don’t smoke
8. Avoid or limit alcohol; alcohol increases inflammation in the gut
9. Maintain normal vitamin D levels – if you don’t know yours – check! Low vitamin D is associated with gut inflammation.

Choose the plan that fits your lifestyle.

Many diets above lower inflammation and have been directly linked to lowering gut permeability/leakiness. With this in mind, the best “diet” for ‘leaky gut” is one that fits your individual needs and lowers inflammation and leaky gut symptoms. And has the following characteristics:

• Is the least restrictive
• Can be followed long-term
• Focuses on real food and contains predominantly plant-based foods (if tolerated)
• It is high in fiber.
• Limits or eliminates processed foods such as chips, cookies, pretzels, etc.
• Eliminates foods you may react to, as determined by an elimination diet if necessary
• Limits or eliminate added sugar as found  in candy, cakes, juices, sodas
• Looks closely at common offenders: dairy, FODMAPs, nightshades, sugar, and gluten. Not everyone reacts to these foods. They are common triggers that may need to be eliminated or reduced.

Disclaimer:

• In most diets discussed, a direct connection between leaky gut and intestinal permeability has yet to be validated. That doesn’t mean it doesn’t exist. Research takes time and often lags behind what is seen to be helpful in real-life situations. In my humble opinion, if interventions help someone feel better and are not harmful, I am comfortable using clinical judgment. Medicine is not perfect.
• Whether or not you agree with the presence of a “leaky gut” as an entire disease process – there is no debate that inflammation is harmful and any dietary intervention that can decrease inflammation is good.
• I don’t recommend long-term adherence to restrictive diets unless medically necessary. Maintaining emotional and physical health on a highly restrictive diet is difficult. The risks and benefits need to be weighed. Professional assistance may be required.
• The ultimate goal is achieving the least restrictive, least inflammatory diet possible. Know that eliminating particular food might not have to be forever – with diet and lifestyle changes, we can cultivate better gut health and tolerate and enjoy a greater range of food choices and better overall health (44)!