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Foods That Cause Leaky Gut

By Liam McAuliffe Updated on

“Leaky gut” refers to a syndrome in which gaps form in your intestinal wall. These gaps allow bacteria, sugar, and plant toxins to cross the intestinal barrier and enter your bloodstream. Though leaky gut is a relatively new area of study, many common foods have been found to contain compounds that cause leaky gut. 

Also known as “increased intestinal permeability,” leaky gut has been associated with various chronic inflammatory and autoimmune diseases, including arthritis, celiac disease, and diabetes. 

In this article, we’ll explore the foods that cause leaky gut. We’ll also offer an anti-leaky gut food list. 

Table of Contents

What is Leaky Gut? 

Leaky gut is the colloquial name for increased intestinal permeability.

Our intestines comprise more than 4,000 square feet of surface area, all of which is protected by a mucosal membrane. When this membrane is healthy it controls what nutrients and compounds get absorbed into our bloodstream–allowing only those that are beneficial.1 2 

diagram of a healthy intestinal barrier


Foods that damage the intestinal lining create gaps between mucosal membrane cells. These gaps allow plant toxins, antinutrients, bacteria, sugars, pesticides, and undigested food particles to enter your bloodstream. 3

diagram of leaky gut


Once in the bloodstream, these particles are carried to various organs and tissues in the body, where they either cause direct damage or are detected as antigens by your body. Your body responds to antigens with an inflammation. 

If leaky gut goes unchecked, it can lead to chronic inflammation, autoimmune disorders, advanced aging of joints and organs, and mood disorders, among other issues. 

The good news is that the root of this syndrome is likely the foods we eat that cause leaky gut. 

Eliminating the foods that cause leaky gut and replacing them with foods that support your gut lining can restore your health from the gut up. 

Leaky gut is also implicated in numerous other disorders: 

Gastric ulcersAllergies
Infectious diarrheaInfections (e.g., respiratory)
Irritable bowel syndrome; functional gastrointestinal diseasesAcute inflammation (sepsis, systemic inflammatory response syndrome, multiple organ failure)
Inflammatory bowel disease, Celiac diseaseChronic inflammation (e.g. arthritis)
Cancer (esophagus, colorectal)Obesity-associated metabolic diseases (nonalcoholic steatohepatitis, diabetes type I and II, cardiovascular disease)


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What Causes Leaky Gut?

Though research on the causes of leaky gut is still emerging, numerous foods are shown to contain compounds that directly contribute to increased intestinal permeability. 

Let’s take a look at these gut-harming compounds and the foods that contain them. 

Toxins in Plant Foods that Harm Your Gut

Plants don’t have feet, fists, fangs, or other obvious ways of defending themselves. But like all other life forms, plants want to survive and replicate. To achieve goals, plants evolved an arsenal of chemical defenses known as plant toxins and antinutrients.

The human body’s first line of contact with these plant defense mechanisms is in our gut lining. 

It is no surprise then that plant toxins and antinutrients are key factors in intestinal permeability. Though most cultivated plant foods are not acutely poisonous, repeated low-dose exposure can result in leaky gut

Common plant compounds that cause leaky gut include:

Furthermore, a large proportion of grains, spices, and dried fruits, are contaminated with bacteria and mycotoxins (toxic molds) that are also implicated in intestinal permeability. 1 2

Leaky gut Syndrome concept. Comparison of healthy organ and inflamed tissue cells. Diseases of gastrointestinal tract. Toxins and viruses. Cartoon flat vector illustration isolated on white background

Let’s take a look at the specific toxin-laden foods that cause leaky gut.

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Foods that Contain Gluten

Foods with gluten can cause leaky gut in various ways. 

Research has shown that high levels of a protein called zonulin increase intestinal permeability.6 7 

Two known factors stimulate high levels of zonulin–gluten and bacteria. 8

Studies consistently show that in people with and without celiac disease, gluten increases intestinal permeability and can result in various other digestive issues. 9 10

Furthermore, most glutenous products are high in carbs and lectins, both of which can cause leaky gut. 

How Gluten Affects Your Gut

When a part of the gluten molecule called gliadin enters your gut your body senses a threat and reacts with an inflammatory immune response. 


The ensuing inflammation in your gut lining damages and flattens your intestinal villi. The villi are a protective hair-like structure lining your gut. Inflammation and damage to this structure can result in a leaky gut. [4]

diagram of intestinal permeability due to lectins

The damage from gluten can happen relatively quickly on a biological scale. 15 hours after consuming foods with gluten, fragments of gliadin enter the bloodstream, where they begin to cause inflammatory damage to other body tissues.

High Gluten Foods That Cause Leaky Gut

Wheat-based foods like bread, pasta, cereal, crackers etc. Raw wheat and wheat germ contain around 300 mcg of lectins per gram [15]. While whole wheat flour contains around 30 mcg of lectins per gram [16].

Other wheat derived high gluten foods include: 

  • wheatberries
  • durum
  • emmer
  • semolina
  • spelt
  • farina
  • farro
  • graham
  • KAMUT® khorasan wheat
  • einkorn wheat
  • Rye
  • Barley
  • Triticale
  • Malt in various forms including: malted barley flour, malted milk or milkshakes, malt extract, malt syrup, malt flavoring, malt vinegar
  • Brewer’s Yeast

Foods High in Sugar 

Unhealthy products. food bad for figure, skin, heart and teeth. Assortment of fast carbohydrates food with fries and cola

Recent studies have shown that diets high in sugar, like the Standard American Diet, increase the relative abundance of bacteria that cause intestinal permeability called Proteobacteria. 

At the same high sugar diets decrease the abundance of gut-protective Bacteroidetes. These beneficial organisms have been shown to reinforce gut barrier function and defend against endotoxins. 1

Other studies have found that high sugar diets disrupt the integrity of the intestinal barrier leading to systemic autoimmune responses.2

Furthermore, low levels of healthy gut bacteria may have the same effect. This is called gut dysbiosis. 17

Foods high in sugar that cause leaky gut

To reduce the effects of sugar on leaky gut, eliminate added sugars and high carb foods, including: 

  • Candy 
  • Soda
  • Baked goods like cookies, cakes, pastries
  • Bread products–sandwich bread, bagels, pita bread etc. 
  • High-carb vegetables
  • High-carb fruit

Foods High in Lectins

Lectins are sticky proteins that bind to carbohydrates. 

Pea lectin protein. Carbohydrate binding protein isolated from Pisum sativum. Cartoon & stick representation with backbone gradient coloring.

In plants, these proteins defend against pests [1]. But when consumed by humans, they can bind to the lining of your gut, resulting in inflammation and contributing to leaky gut. [7] [8]

Studies show that when lectins bind to cells lining your gut they can disrupt the growth of healthy bacteria and inhibit hormone signaling. 7]

Additionally, lectins inhibit digestive enzymes needed for properly metabolizing food, and they bind to zinc, iron, and calcium. [2]

Studies also show that lectins increase inflammation associated with IBS and autoimmune conditions like rheumatoid arthritis [9].

If you already have IBS or leaky gut, you are more susceptible to the negative effects of lectins and can experience them immediately.[7]

Damage from lectins to the gut can reduce your ability to absorb protein, fat, and vitamin B12, which increases your risk of inflammatory bowel disease. [31]

With repeated exposure over time, lectins can attach to insulin receptors, leading to insulin resistance, high blood pressure, inflammation, and type 2 diabetes [20][21][22]

High Lectin Foods That Cause Leaky Gut 

Foods high in lectins include: 

  • Legumes like kidney beans, soybeans, and peas. Legumes are also high in carbs and fiber, which can contribute to intestinal dysbiosis associated with leaky gut
  • Wheat-based products (gluten is a lectin), including bread, baked goods, pasta, cereals, wheat flour, couscous, etc.
  • Peanuts. Studies have found lectins in the bloodstream of groups of people ate both roasted and raw peanuts. [8] Lectins from peanuts have also been found to cross the intestinal barrier into the bloodstream.
  • Tomatoes: lectins in tomatoes are not eliminated by high heat processing [24]. Tomatoes also contain a plant toxin called tomatine that can accumulate in the body and become mobilized in times of stress.[14].
  • Corn:  Accounting  for around 60% of global food production, many people eat corn that is minimally cooked, allowing lectins to pass into the gut
  • Squashes including pumpkin, acorn squash, zucchini, and butternut. Lectins in squash are found mostly in the skins and seeds [35]
  • peppers (bell and hot peppers, including jalapenos)
  • eggplants
  • goji berries
  • potatoes

High Oxalates Foods

Oxalates are another class of naturally occurring plant compounds that help plants but can harm humans.[1]

calcium oxalate crystal in urine analysis.

In your gut, oxalate crystals act as microscopic spears that abrade your intestinal lining and are significantly associated with intestinal fungal infections. [9] [10] [11] [12]

In addition to their direct assault on the gut lining, oxalates have been found to suppress immune function, reduce mitochondrial activity, and lead to the formation of kidney stones.[3][6]

High Oxalate Foods That Harm Your Gut

High oxalate foods include many of the most popular fruits, veggies, and seeds: 

  • Spinach: Just a 100-gram portion of spinach contains approximately 645 milligrams of oxalate
  • Cocoa
  • Beets
  • sesame seeds
  • Rhubarb
  • sweet potato
  • Coriander
  • Currants
  • spinach 


Due to their high lectin and glycoalkaloid content,  potatoes deserve their own category. 

Glycoalkaloids attack the energy centers (mitochondria) of your red blood cells. This process is known as “cell-rupturing.” Research has found that cell-rupturing is implicated in leaky gut.” [3][4]. 

Glycoalkaloid toxicity from potatoes can occur after consuming just 1 mg of glycoalkaloids per kg body weight. 

For the average 150 lbs person, toxicity can occur after eating only 68 mg of glycoalkaloid. Fatality can occur after consuming 302 mg. 

Due to these dangers, the maximum allowable level of glycoalkaloids is 20 mg of total glycoalkaloids per 100 g (fresh weight) of potatoes. [10]

Glycoalkaloid levels in common potato products [11]

POTATO CHIPS (1 OZ BAG).36-.88 mg.29-1.4 mg 2.7 -12.4 mg/28-gram bag
FRIED POTATO SKINS (4 OZ)4.4-13.6 mg2.0-9.5 mg6.4- 23.1 mg/4 oz
Dr. Kiltz's Take
It’s fine to enjoy fresh potatoes fried in tallow once in a while. We can get into trouble when we make a habit of consuming this high-carb food all the time, especially when fried in toxic vegetable oils, and from sources where we don’t have a way of making sure the potatoes are in good condition. 

Vegetable Oils

Vegetable oils are highly processed industrial products that are bad for your gut. 

Most vegetable oils are made from GMO crops that are engineered to contain extra high levels of lectins in order to resist pests. 

Conventional seeds and legumes are also sprayed with the pesticide glyphosate (Roundup), which has been shown to have extremely negative effects on gut health. In fact it may be the main reason behind the dramatic rise in Celiac disease. 

Vegetable oils also contain high percentages of omega-6 fatty acids, which are linked to inflammation [28].

Common vegetable oils include: 

  • Corn oil
  • Soybean oil
  • Sunflower oil
  • Safflower oil
  • Canola oil

Food Contaminated with Mycotoxins

electron microscope image of mycotoxin

Mycotoxins are toxic compounds that form when certain molds grow on plant foods. 

As the world warms and becomes more humid, mycotoxin exposure is a growing threat. [1] [2]

Studies show that mycotoxins cause leaky gut by attacking all four aspects of intestinal protection, including mucosal (physical), chemical, immunological, and microbial barriers. 3

Foods High In Mycotoxins That Cause Leaky Gut

The following foods often contain mycotoxins that cause leaky gut:

  • Grains: corn, wheat, barley, rye
  • Nuts: peanuts, pistachios, and Brazil nuts
  • Sugar: from cane and beets
  • Coffee beans 
  • Chocolate 
  • Dried fruit: apricot, figs, plums, dates, quince
  • Beer and wine
  • Spices

Food to Eat to Heal Your Gut

Now that we’ve identified that plant food, processed foods, and high sugar foods cause leaky gut, let’s turn to the foods that can nourish your gut. 

This leaves whole food animal products. These foods high in nourishing fats, proteins, and meat-specific micronutrients help resolve dysbiosis, and lift the toxicity burden.  [24] [25]

For people with leaky gut, IBS, and other gut issues, a carnivore elimination diet, AKA Lion Diet, can be an exceptionally effective approach.

A 2019 study by Dr. Sawn Baker’s Revero health program, surveying over 12,000 participants in carnivore diets, found that 95% reported improvements in gastrointestinal conditions. 

Gut-Healing Foods List

Carnivore diet concept. Raw ingredients for zero carb diet - meat, poultry, fish, seafood, eggs, beef bones for bone broth and copy space in center on gray stone background. Top view or flat lay.

Below you can find a list of nutrient-dense foods, many of which are high in vitamin A (retinol)

Retinol has been shown to be inversely associated with intestinal permeability (7)


RuminantsPorkPoultryfishseafoodOrgan meatsWild meatsfatEggsDairyFruits and Veggies




All typesChicken



Game hen










Arctic Char





























Chicken eggs

Duck eggs

Goose Eggs

Ostrich eggs

Quail Eggs




Creme Fraiche





Foods That Cause Leaky Gut: The Bottom Line

The gut is the first physiological defense against food contaminants. 

Repeated exposure to contaminants can compromise the four aspects of intestinal protection, including mucosal (physical), chemical, immunological, and microbial barriers.

When this happens, gaps can form between the cell structures of your gut, allowing contaminants to pass into your bloodstream, where they can spread to every other part of your body. This syndrome is called leaky gut

The foods that cause leaky gut are high in various gut-harming compounds, including: 

  • Gluten
  • Oxalates
  • Lectins
  • Various other plant toxins and antinutrients
  • Sugar
  • Mycotoxins

Common foods that cause leaky gut include

  • Wheat products
  • Legumes
  • Processed foods
  • Foods high in sugar
  • Plant foods high in oxalates 
  • Plant foods high in lectins
  • Plant foods contaminated with mycotoxins

To avoid foods that cause leaky gut, limit your exposure to these foods, and replace them with nourishing foods free of contaminants, including fresh meat and unprocessed animal products. 


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