Leaky Gut

Dr Thanh-Tam Pham - 01/01/2022

Leaky gut, also called increased intestinal permeability, is somewhat a new concept and many doctors may not recognize this term. We already know that, increased intestinal permeability plays a role in conditions such as coeliac disease, Crohn’s disease and irritable bowel disease. Some studies show that leaky gut may be associated with other autoimmune diseases (Rheumatoid arthritis, lupus, type 1 diabetes, multiple sclerosis), chronic fatigue syndrome, fibromyalgia, arthritis, allergies, asthma, acne, obesity and even mental illness.

The lining of the intestine is made of millions of cells joined together by tight junctions to create a barrier that acts as a security system and it has a job to decide what gets absorbed into the blood stream and what cannot. This barrier is only one cell thick and covers a large area of the size of a double tennis court.

In an unhealthy gut, “holes” develop in the barrier resulting in toxins and bacteria leaking into the body triggering inflammation in the gut and throughout the body causing a chain reaction of problems, such as bloating, gas, cramps, food sensitivities, fatigue, headache, joint pain…


Within the intestinal tract live hundreds of trillions of different microbes, viruses, fungi, parasites. In fact, 90 percent of all the cells of our body are nonhuman. Those microbes rely on us to house and feed them but we are equally dependent on them. Germ-free mice are shorter and smaller, live shorter lives and are more susceptible to disease because their immune system never develops properly. The microbiome is the most important trainer and guide for the immune system to determine if and when it should unleash inflammation. The microbiome of a baby is completed in the first 3 years of life and a diverse and well balanced microbiome helps to ensure the long term development of a healthy immune response. Babies who are born vaginally will receive microbial imprinting from their mothers whereas babies born by caesarian section mostly receive skin microbiome from mother, nurses and hospital environment.

Keeping intestinal microbes in their place is difficult because the intestinal barrier has 2 contradictory jobs, that is to let nutrients in and preventing unwanted bacteria or foreign substances to get into the blood stream. This physical barrier is made of several components. The two most important are the epithelial monolayer with its intercellular tight junctions and the mucus layer composed mainly of proteins. The main function of these two components is to segregate the luminal gut microbiome from the host immune cells. The outer mucus layer is inhabited by a large number of intestinal microbes while the inner mucus layer is free of germs thanks to the action of secretory IgA . With the absence of dietary fibre, which is the main food source of many intestinal bacteria, leads to the expansion of mucin-degrading species, resulting in the increase of inner mucus degradation, potentially jeopardizing the segregation from the host immune cells.

In 2000, Dr Fasano and his research team discovered zonulin, the only currently known physiological modulator of gut permeability. Zonulin make the tight junctions gates to open. Gliadins, key components of gluten can trigger that response and increase gut permeability.

Breaching the gut wall:

The two most powerful triggers of zonulin release are an unbalanced microbiome (dysbiosis and/or small intestinal bacterial overgrowth- SIBO) and gluten exposure according to Dr Fasano. Zonulin is increased when there is an enteric infection that may represent a defensive mechanism that “ flushes out” microorganisms, contributing to the innate immune response of the host against bacterial colonization of the small intestine. Gliadin binds to the receptor CXCR3 is crucial for the release of zonulin and the subsequent increase in intestinal permeability. CXCR3 is overexpressed in Coeliac patients.

According to Dr Gundry, some food and drugs can cause damage to the gut lining, such as pain killers, nonsteroidal anti-inflammatory drugs (NSAIDS), lectins and lipopolysaccharides (LPSs).

Lectins are big sticky proteins that can pry apart the tight junctions between the cells allowing larger molecules to pass through into the body such as bacteria, proteins stimulating the immune system causing chronic inflammation.

Friendly bacteria, which populate the innermost layer of cells in the gut thrive on complex resistant starches. These bacteria not only live in mucus, they also stimulate mucosal cells to make more mucus. Mucus then acts as a moat to trap lectins and block them from passing through the intestinal border. NSAIDS can cause gaping holes in the mucus-lined intestinal barrier. Antibiotics, acid blocking drugs can change the gut flora and the mucus layer of the gut.

According to Dr Gundry, lectins are toxins that plants produce to survive and they should not be eaten because they can cause inflammation, intestinal damage and weight gain. Although some lectins are dangerous, many foods that contain lectins are nutritious with fibres, proteins, vitamins, minerals and anti-oxidants. Cooking destroys lectins.

Chronic inflammation and autoimmune diseases:

Coeliac disease is a typical example of a chronic inflammatory condition. It is the only autoimmune disease that we know the trigger and once gluten is eliminated, the autoantibodies disappear and symptoms resolve.

Irritable Bowel Syndrome:

IBS is characterized by recurrent abdominal pain associated with irregular bowel habits such as diarrhea or constipation. Classically, IBS was regarded as a gut-brain axis dysfunction. Miscommunication between neuroendocrine signaling and effector nerves within the gastrointestinal tract, caused by psychosocial stressors and leading to visceral hypersensitivity and altered motility. There is now new evidence that exposure to environmental stimuli such as food, infections, antibiotic treatment and psychosocial events is playing a role in the pathogenesis of IBS.

Small Intestinal Bacterial Overgrowth (SIBO)

SIBO is characterized by an increase of the presence of both symbiotic and pathogenic species of microbes in the small intestine. Breath Hydrogen test is not highly accurate for diagnosing SIBO. SIBO can be treated with antibiotics rifaximin and probiotics. SIBO and IBS are tightly interconnected.

Autoimmune diseases:

We have no effective cure for autoimmune diseases. Patients face a lifetime illness and palliative treatment aimed mainly at putting a brake on the immune system to ameliorate the inflammatory process.

In the past few decades, the incidence of autoimmune diseases has increased considerably and there is increasing evidence of a correlation between the presence of microbiome dysbiosis and the development of autoimmune conditions. There is strong evidence that the human microbiome is able to shape the host immune response. Therefore, the manipulation of the microbiome could represent a potential therapeutic strategy for the improvement and potentially complete restoration of the normal immune response in autoimmune diseases, a concept unthinkable until recently, but still not completely accepted within the scientific community.

Manipulation of the human microbiome:

It offers a more natural and more acceptable therapeutic approach to chronic inflammatory diseases. One of the most important lessons to be deeply explored in longitudinal studies aimed at disease prevention is diet. The negative impact of a poor diet on health and its role in chronic disease is now taking a centre stage at global level.

         ●   Prebiotics: the three criteria of prebiotics are (1) to be resistant to digestion in the stomach and upper intestine; (2) be fermentable by the gut microbiota; and (3) specifically stimulate the growth and/or activity of intestinal bacteria beneficial to our health.

         ●   Probiotics are live microorganisms with health promoting properties. A few of the most studies probiotics are Lactobacillus GG ( Culturelle) for acute diarrhea in children, allergies and atopic dermatitis. Colicky infants may need Lactobacillus reuteri.

            Lactobacillus plantarum in fermented oats prevented multiorgan failure in patients of Dr Bengmark after undergoing liver surgery instead of using antibiotics.

            Some studies using Vivomixx in autistic children showed some improvements in the severity of ASD.

            If take antibiotics, take probiotics in between the antibiotic dose, make sure they have Lactobacillus brevis.

            Probiotics have many different strains: Lactobacillus plantarum, Lactobacillus acidophilus, Lactobacillus brevis, Bifidobacterium lactis, Bifidobacterium longum.

         ●   Synbiotics are defined as “synergistic mixtures of probiotics and prebiotics,

         ●   Postbiotics are functional , fermentation-soluble factors, products that are actively secreted by live bacteria.

The Plant Paradox

Dr Gundry was a cardiothoracic surgeon and in 2002, he left his position as Head of Cardiothoracic Surgery at Loma Linda University to found The Center for Restorative Medicine and since, spent at least 14 years studying the human microbiome.

There haven’t been any human studies to back up Dr Gundry’s claim but lectins can cause health problems when eaten in high doses.

Lectin free food: foods to eat

         ●   Protein: grass fed, pasture raised poultry, free range eggs, wild caught fish and hemp products.

         ●   Starches and grain free products: sweet potatoes, plantains, parsnips

         ●   Nuts and seeds: macadamia, walnuts, pecans, hemp seeds, sesame seeds, hazelnuts.

         ●   Fruits: avocadoes, berries, coconut

         ●   Vegetables: mushrooms, broccoli, spinach, brussel sprouts, asparagus, okras, carrots, radishes, beets, kale, cabbage

         ●   Dairy: goat’s milk and cheese, organic sour cream, organic cream cheese

         ●   Fats and oils: grass fed butter, olive, coconut, avocado oils

Foods to avoid:

         ●   Protein: soy products, grains or soy fed livestock, farmed fish, all beans and legumes.

         ●   Grains and starches, pasta, potatoes, cookies, crackers, pastries, wholegrain, wheat, rice, oats, quinoa, barley, corn and pop

         ●   corn.

         ●   Nuts and seeds: sunflower seeds, pumpkin seeds, chia seeds

         ●   Fruits: all fruits except berries

         ●   Vegetables: cucumbers, zucchini, pumpkin and other squashes as well as nightshades like tomatoes, bell peppers and eggplant

         ●   Dairy: all conventional A1 milk products as well as Greek yogurt, cheese and cottage cheese

         ●   Fats and oils: vegetable, soybean, canola, corn, peanut and sunflower oils

According to Dr Gundry, you can eat tomatoes, bell peppers and cucumbers if they’ve been peeled and deseeded.


Gut feelings- The Microbiome and our Health- Dr Alesso Fasano and Susie Flaherty.

The Plant Paradox- Dr Gundry

Brain Maker: The Power of Gut Microbes to Heal and Protect Your Brain- for Life- Dr David Perlmutter