What is Leaky Gut?

Leaky gut is linked to inflammation and the origin of many chronic diseases.

Understand Leaky Gut

Our intestines have a thin layer of cells covered by mucus. This unicellular (one cell) thin layer separates the intestines from the bloodstream. Imagine our bloodstream as an avenue to the rest of the body, and all the organs. This layer covered  by mucus serves as a barrier to pathogens such as (bad viruses, bad bacteria, bacteria endotoxins, other toxins, etc.) coming through the intestines trying to invade the bloodstream. Figure 1 shows a healthy gut versus a leaky gut. On the left is a healthy gut covered by a thick layer of mucus. The cells are all connected by tight junctions. These connections are crucial to keep these cells together, as a “wall” preventing foreign substances to invade the bloodstream.  On the right, the mucus layer has become thin, and in some parts, nonexistent. Some of the tight junctions are compromised and many cells are no longer “tied together.” This causes toxins, pathological microorganisms, allergens, protein, and bacterial toxins to “leak” into the bloodstream. That’s why the name “leaky gut”. Leaky gut is a higher permeability of the intestinal barrier into the bloodstream, also called gut dysbiosis.

Figure 1.: A healthy gut versus a leaky gut


Consequences of Leaky Gut

Inflammation is triggered when harmful substances “leak” into the bloodstream, which is now believed to linked to the foundation of many known chronic diseases. Hippocrates, the father of medicine said 2,000 years ago: “All diseases start in the gut”. Was he right? 2,000 years later, we discover through well-designed studies that your gut health can affect your weight, mood, emotions, immunity, hormones, and can trigger inflammation, for it’s the underlying cause, or the genesis of several chronic diseases.

Good Gut Bacteria keeps Gut Integrity

A healthy gut is linked to our gut microbiome. We have around 39 trillion microorganisms located in our colon (see figure 2). Most of them are bacteria. Good bacteria play a crucial role in human health – more than we could imagine. These microorganisms are alive and active, helping the body to coordinate complex tasks, as in a beautifully harmonized orchestra. An example of how good bacteria keeps gut integrity is that they produce short chain fatty acids such as butyrate, acetate, and propionate. These are some of the most powerful anti-inflammatory substances known! Butyrate acid, for instance, “repairs” the cells’ tight junctions, thus preventing leaky gut!! Bacteria also produces mucus to protect our gut and our health.  Humans have in average 300 to 1000 different species of bacteria in the gut. The more diversity of good bacteria the better. They have specialized roles that contributes to human health, (see figure 3).

Figure 2: Gut Microbiome


Figure 3: Bacterial Diversity


Amazing facts about our gut microbiome

  1. The gut is now considered our “second brain,” as it is composed of 500 million nerves. There is constant communication between the gut and the brain through the vagus nerve. Have you ever felt nervous, leading to diarrhea? Such a condition is due to this connection between the gut and the brain. Do you want to have a better mood? Well, 90% of serotonin – the “happiness” hormone – and 50% of dopamine – a hormone that makes you feel good- are produced in the gut by microbes! That means a healthy gut will make you feel better and an unhealthy gut will do the opposite. See image below:

Figure 4: The gut-brain connection


2.   70% of the immune system is contained in the gut and gut microbes help the immune system identify threats, including cancer cells. They are like sergeants leading an army of immune cells. Problems with the gut can lead to food allergies and sensitivities, auto-immune conditions, because the immune system will overreact. A healthy gut balance the immune system!

What causes leaky gut first place?

In a nutshell, fiber and fermented foods are the only foods which support good gut health. If your diet is low in fiber, your health will suffer! If you do not feed your bacteria fiber, they will not produce the short-chain fatty acids, thus no repair of the tight junctions, resulting in reduced mucus production. Because they are starved in a low-fiber diet, bacteria will start munching on the gut mucus and cause a leaky gut. One can find fiber exclusively in plant foods, especially whole plant foods (fruits, vegetables, nuts, seeds, legumes). Gut health is crucial to overall health since the gut microbiome is involved in many body functions. Good bacteria biodiversity is critical to health promotion and longevity and the key to a healthy gut is a healthful gut-promoting diet. A leaky gut can be reversed by fostering good bacteria.

Stay tuned for my next blog, “How to Reverse Leaky Gut through a Better Diet”.



Posted: November 21, 2023

Category: Health & Nutrition
Tags: Fiber, FiberAndGutHealth, GutBacteria, GutBrainHealth, GutHealth, GutMicrobiome, Inflammation, LeakyGut

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