Microbiome and gut health
Is your gut leaky?

Lets face it: exposure to certain factors makes our gut leak!

Scientists all over the world are working hard to unravel the puzzles on the growing incidence of many diseases, particularly in Western countries. It will take time before we get all the pieces together, but what we already know is that many diseases are linked to poor diet, gut dysbiosis, pollution, and stress, to name a few. Our Western diet has changed over the last two to three decades, from simple and unprocessed foods to highly processed foods with high sugar content. Coincidently, as we eat more processed foods, there is also a growing number of diseases, including autoimmune diseases. So the primary question arises: What’s the link between a poor diet and how our Westernized diet make us sick? Multiple factors are often involved, such as genetics, environment, lifestyle, and diet. They determine why some people get sick while others do not. Diet is undoubtedly a very important factor in our well-being. As Hippocrates stated “Let food be thy medicine and medicine be thy food.” Diet choice may have a profound effect on our health. Actually, a poor diet is one of the factors that has been linked to a leaky gut and consequently to diseases. Let’s find out what a so-called leaky gut is.

Intestinal barrier and intestinal permeability

What exactly stands behind a “leaky gut”? A leaky gut commonly refers to an increased permeability within the intestinal wall. This condition is sometimes called a “leaky gut syndrome.” Permeability allows certain molecules and ions to pass through the (intestinal) membranes. A leaky gut can be associated with food sensitivities, cramps, gas, bloating, and/or aches, pains, and diseases. To better grasp it, let’s define first “intestinal barrier” and “intestinal permeability.

Intestinal barrier refers to a complex intestinal structure of the digestive tract that includes vascular endothelium, the epithelial cell lining with tight junctions, and the mucus layer. It anatomically separates what’s within our digestive tube (microorganisms, food particles, or drugs) from what’s outside of it (immune cells, blood vessel, smooth muscles, enteric nervous system). The intestinal barrier serves to protect us from harmful staff such as microorganisms or toxins.

Intestinal permeability on the other hand, facilitating the passage between the inside (inner host) and the outside (lumen) of the intestinal lining, allows us to selectively absorb nutrients, liquids and to respond to the triggers present within the gut. Intestinal permeability is an intestinal barrier feature that selectively lets some molecules in and others out. Factors such as microbial gut imbalance, infections, some foods, exposure to chemicals, toxins, alcohol, or stress may alter-increase the intestinal permeability, as well as possibly damage the intestinal barrier by forming tissue lesions and punctures that could lead to a leakage –  a leaky gut. One of issue is it may lead to the translocation of undesired luminal gut content (microorganisms, toxins, gluten, undigested food particles) into the host (into tissues, into blood vessels), activating an immunological response. Intestinal epithelial tight junctions are another key players (proteins) keeping our intestinal barrier intact by functioning as a seal between neighboring gut cells. Disrupted epithelial tight junctions can be found in a leaky gut.

Regulation of gut permeability: what to blame for an increased intestinal permeability?

Besides genetics, environmental factors also play an important role in keeping our intestinal barrier intact with normally functioning permeability. Possible harmful factors include nutritional factors, pathogens, toxins, too clean/sterile environment (the hygiene hypothesis), too low microbial gut diversity with impaired microbial functioning (the lifestyle hypothesis), or endogenous factors (chronic inflammation/autoimmunity).

Intestinal permeability may be influenced by:

1. The gut microbiota - dysbiosis

The gut microbiota is involved in a number of processes, such as the production of vitamins and hormones, metabolism and absorption of nutrients, and protection against pathogenic organisms. There is constant fine-tuning between the host’s immune system and the gut microbiota to maintain an equilibrium-homeostasis state and promote health. The healthy gut microbiota stimulates the synthesis of protective mucus (mucus sugars) lining by the gut epithelial cells. Some bacteria regulate the mucus layers by using the mucus components as an energy source so there is no mucus overgrowth. There is a regulation at multiple levels between the gut microbiota and the intestinal barrier. If the microbial gut ecosystem is out of balance, leading to dysbiosis and/or increased activity of pathogens, it may in turn promote inflammation, altered intestinal permeability and gut barrier damage. For example, some pathogens such as Helicobacter pylori, Salmonella eterica serovar typhimur., Clostridium difficile, or Vibrio cholera were shown to disrupt the epithelial tight junctions, increasing the intestinal permeability.

2. Diet

Diet, apart from an individual’s genetic imprint and gut microbiota, may affect to a greater or lesser extent, the gut permeability. Some studies have shown that Vitamin A deficiency may compromise the intestinal lining. Additionally, Vitamin D deficiency may potentially have a similar effect. Short chain fatty acids (SCFA), such as butyrate, produced by the gut microbiota play an important role in intestinal barrier formation and maintenance. Individuals suffering from Irritable Bowel Disease (IBD) were shown to have intestinal permeability and barrier impairment that has been linked to the deficit of butyrate, produced by the gut microbiota. In addition, A1 casein present in dairy cow products may also contribute to the problem. Let’s not forget about the negative effect of the overconsumption of alcoholic beverages. Lectins present in legumes show affinity to intestinal mucosa, which make the mucosa porous and leaky. It has also been demonstrated that commonly used food additives increase intestinal permeability, potentially leading to the gut leakage.

Lets pay some attention to food additives:

Sugars  can be found in most processed foods. Glucose is an absorption enhancer and an increased gut permeability is required for its absorption. It has been shown that the presence of glucose affects the distribution of an intestinal barrier related protein (Caco-2), which may lead to the disruption of intestinal tight junctions and consequently to the intracellular leakage.

Salt – usually overconsumed, salt has been associated with strokes, hypertension, renal diseases and obesity. About 75% of sodium intake comes from manufactured foods, such as baked goods or cereals. Recent studies indicated that increased salt consumption enhances the intestinal permeability by disrupting the functioning of claudins (2 and 15) and proteins, which are the backbone component of the intestinal tight junctions.

Emulsifiers/surfactants there is plenty of these substances available and used in the food industry. The emulsifier market is growing worldwide. The list is long but commonly used emulsifiers include mono-and di-glycerides of fatty acids, sucrose esters of fatty acids, polyglycerols of fatty acids, lecithin, glycolipids, saponins, unsaturated and saturated/trans fatty acids. They are widely used in the bakery products, dairy, sauces, margarine, ice cream, beverages, chocolates and many other products. Many (synthetic) surfactants are shown to increase intestinal permeability. For example sucrose monoester fatty acids, which are widely used in the food industry – even in infant formula - have been shown to compromise the intestinal integrity of tight junctions.

Organic solvents - used to dissolve another substance. They need to be handled under special conditions as they are poisonous. Some commonly used organic solvents in the industry are benzene, xylene, toluene, acetone, hexane, ethanol, and some detergents. They are typically used in the process of extraction of active compounds and/or removal of unwanted substances, such as in oil production. Some are used as food additives. For example, alcohol and its metabolites were shown to breach the intestinal barrier.

Gluten – typically to be found in wheat derived products. Gliadin, one of gluten’s proteins, in known to increase the gut permeability and to contribute to intestinal damage.

Microbial transglutaminase – an enzyme of microbial origin commonly used in industry to simplify certain manufacturing processes related with economic savings. It is used to improve the texture and appearance of meat, fish, dairy products, bakery products, and sweet products, among many others. Scientists are alarmed that microbial transglutaminase may increase intestinal permeability by affecting/cross-linking certain amino acids and/or proteins.

Nanoparticles – Particles at dimensions between 1 and 100 nm (nanoemulsions). These nanoemulsions are applied in the food industry in order to protect, encapsulate, and enhance delivery of bioactive components such as lipids, flavors, vitamins, preservatives, and nutraceuticals. Nanoparticles increase the intestinal permeability by facilitating the transport of molecules and drugs through the gut lining. Chitosan is a common component of nanoparticles with the shown ability to enhance permeability and intestinal absorption of active agents.

There are other compounds shown to increase the intestinal permeability, such as L-alanine, tryptophan, and epigallocatechin galat (polyphenol in green tea).

3. Use of medication such as non-steroidal drugs like aspirin, birth control pills, steroid drugs, chemotherapy

4. Chronic Stress

Where does a leaky gut take us to: Diseases on the rise

Over the past decades there has been an increasing incidence of autoimmune and other diseases. Many of them have been associated with increased intestinal permeability and a leaky gut. The entry of foreign antigens (toxins, microorganisms, gluten, etc) to the inner host, due to the increased intestinal permeability and leakage, can, in susceptible individuals, initiate immunological-autoimmunological responses.

How do I heal a leaky gut?

  • Eliminate (if known) foods (gluten, sugar, dairy products, GMO products etc) and factors (stress, toxins, pesticides) causing a leaky gut
  • Drink Bone Broth = proline, glycine and collagen will soothe and help repair the gut lining
  • Eat healthy and raw foods (vegetables) = Feed yourself and your gut microorganisms nutritious foods
  • Reduce sugar consumption (consider a low FODMAP diet) and processed fat consumption = avoid energy-dense western diet
  • Avoid processed foods. They contain a lot of food additives that may compromise the gut lining and barrier and compromise your bodies’ acid-alkaline balance
  • Eat probiotic (kefir, sauerkraut, kimchi) and prebiotic (leak, chicory root, onions, banana) rich foods
  • Consider L-Glutamine supplementation
  • Consider probiotic supplements (with Lactobacillus plantarum, Lactobacillus rhamnosus GG, Lactobacillus casei, Lactobacillus salivarius, E. coli Nissle 1917)
  • Add anti-inflammatory foods (Omega-3 rich) to your menu
  • Consider Zinc supplementation (zinc carnosine)
  • Consider Quercetin supplementation
  • Consider Vitamin A supplementation

How do I know if I have a leaky gut? Are there any lab tests?

Suffering from any of above mentioned diseases may indicate you have an impaired intestinal permeability and an impaired intestinal barrier. Discomfort related to food sensitivities, cramps, gas, bloating, and/or aches and pains may also be a sign.


“Intestinal permeability – a new target for disease prevention and therapy”. Bischoff at el., BMC Gastroenterology 2014, 14:189

“Changes in intestinal tight junction permeability associated with industrial food additives explain the rising incidence of autoimmune disease”. Lerner & Matthias, Autoimmunity Reviews 2015, 479-489.

“Intestinal permeability regulation by tight junction: implication on inflammatory bowel diseases”. Sung Hee Lee, Intest Res 2015; 13 (1): 11-18.

Category: Microbiome and gut health icon August 14 2015
Author: Dr Joanna Krzeslak-Hoogland

Being inspired by the effect of nutrition, lifestyle and mind on our health, I am dedicated to help people on their journey to wellbeing.

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