Diets for Leaky Gut: Which is Best?

By Amy Burkhart MD, RD

What is the best diet for healing a leaky gut? A leaky gut has been linked to chronic disease and inflammation, two things that negatively impact your overall health. Information regarding leaky gut and ideal treatments is controversial and confusing.

Everyone seems to have a different cure. How do you decide which path to follow? Diet is one part of most treatment options. Is one diet better than another?  Let’s look at leaky gut and the diets that claim to treat it.

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, which 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 illnesses such as autoimmune diseases, IBS, chronic fatigue and others. (1, 2, 3, 4).

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

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

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

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 patients with celiac disease but its significance reaches far beyond the world of 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). Because of 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 diagnosis is made based on a person’s symptoms. That is never ideal.

There are valid methods to study permeability and commercial labs that have created tests claiming to measure it, but in reality the best way to measure gut permeability has not been determined. How exactly the leakiness of the gut correlates with symptoms, and how to best treat it, is also still not studied in humans. Symptoms 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 and potentially alter disease (9).

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

There are many factors that influence our gut health (10). Some things that cause your gut to be more leaky include:

• Certain medications such as NSAIDS, Proton Pump Inhibitors
• Stress
• Diet triggers: processed foods, sugar, gluten, alcohol, high fat diet
• Changes in the microbiome for example due to illness or antibiotic use (11)
• Excessive exercise (endurance athletes) (12)
• Low vitamin D (13)
• Food additives (eg. carboxymethylcellulose, polysorbate-80 and others)
• Smoking
• Obesity
• SugarNot enough fiber in your diet (14)

Inflammation makes the gut more leaky (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, the treatment of 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 so that we may lower inflammation as much as possible.

The primary focus of this article is the dietary component of leaky gut treatment. Our dietary 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 anti-inflammatory diet and lifestyle choices will improve your odds of a future of optimal health.

The following are diets aimed at treating health and digestive problems. Many are also used by people to  “heal their leaky gut”. They are listed in alphabetical order, not order of importance or recommendation.  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 nightshades (tomatoes, potatoes, peppers, eggplant)
• Fruit (in small amounts)
• Fats: olive oil, coconut oil, avocado oil

The goal of the AIP diet is calming the immune system. The AIP diet has been used as an intervention in several disease states, including inflammatory bowel disease (17).

While the theory behind why an AIP diet may be helpful for repairing leaky gut is sound, it is very restrictive and  there are no research studies to back that claim up just yet.

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

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

An elemental diet is one that 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 the supervision of a healthcare provider. 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). This diet is best done under the supervision of a health care provider.

A gluten-free diet eliminates all sources of food 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). 

Gluten has been linked by research to trigger a leaky gut in people with celiac disease (21). It is not yet proven by research that gluten triggers leaky gut in all people although the internet may tell you differently (22).

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

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.

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

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. If we don’t have enough glucose available because of a low-carb diet, our body makes ketones as a substitute fuel.

Ketones are then used for energy but they also suppress hunger. Being able to go 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.

F-O-D-M-A-P is an acronym that stands for a group of carbohydrates that can cause symptoms such as diarrhea and stomach pain 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 health care 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, not determining how they affects gut permeability. 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 is helpful for 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 a specific type of an anti-inflammatory diet based on a high intake of whole fruits and veggies, olive oil, and low intake of sweets, meat and alcohol. For protein, the focus is on fish and beans and minimal red meat.

The Mediterranean eating pattern is protective against many diseases, including cancer and Alzheimer’s. It may also be helpful in preventing and treating 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). There are not yet studies looking specifically at the Mediterranean diet and leaky gut.

There are many varieties of “paleo” diets. In general, a paleo diet is focused on eating “like a caveman” i.e. how humans ate prior to 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 what a paleo diet is. Many include recipes that use a fair amount of added sugars, claiming to be healthier since they’re less processed. Our body isn’t able to distinguish between different kinds of added sugar very well. What is important is not eating too much 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). There are no studies looking directly at gut permeability and the paleo diet.

The Specific Carbohydrate Diet (SCD) diet has been around for almost 100 years. It was originally developed by a physician to help her child with celiac disease. Today it is used for many conditions including inflammatory bowel disease (40).

In spite of 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 overlap with the low FODMAP diet (41).

There is research demonstrating 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 foods that are problematic 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 there are many cookbooks, Whole30 approved brands and blogs to 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, sugar which would presumably decrease inflammation.

AND THE BEST DIET IS……

Many of the diets above lower inflammation and several 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, lowers inflammation 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)
• 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, gluten. Not everyone reacts to these foods.They are common triggers that may need to be eliminated or reduced.

Diet is just one component of improving your gut health and overall health. Here are others!

1. Decrease stress
2. Exercise 30-60  minutes daily
3. Sleep 7-9 hours a night
4. If possible, avoid medications that worsen leaky gut
5. Treat underlying medical conditions
6. Maintain a healthy weight
7. Don’t smoke
8. Avoid or limit alcohol
9. Maintain normal vitamin D levels – if you don’t know yours – check!

In most of the diets discussed, a direct connection to 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 judgement. Medicine is not perfect.

No matter whether or not you agree with the presence of “leaky gut” as an entire disease process – there is no debate that inflammation is bad and any dietary intervention that can decrease inflammation is good.

I don’t recommend long term adherence to restrictive diets unless medically necessary. It is difficult to maintain emotional and physical health on a highly restrictive diet. The risks and benefits need to be weighed. Professional assistance may be needed.

The ultimate goal is achieving the least restrictive, least inflammatory diet possible. Know that eliminating certain food might not have to be forever – with diet and lifestyle changes, we  can cultivate better gut health and be able to tolerate and enjoy a greater range of food choices and better overall health (44)!

THIS ARTICLE IS COPYRIGHTED BY AMY BURKHART, MD, RD.