Better Gut Health: What is Leaky Gut?

Better gut health and how to fix leaky gut

Leaky gut used to be a very triggering phrase. “Leaky gut? Total myth!” is what you might have heard 5 or 10 years ago. While there are still some folks out there who don’t believe it exists, by now, we have an incredible amount of scientific literature not only confirming the existence of leaky gut but also the potential consequences leaky gut syndrome can have on the body and the importance of protecting your gut lining. 

A leaky gut has significant consequences on your immune system health as well as your overall health. Intestinal permeability and dysbiosis (an imbalance of the bacteria in your gut) may be one of the primary sources of inflammation in the general population, besides excess fat tissue. This, in turn, can increase the risk of many different issues; particularly metabolic and cognitive. 

This post is the second in our gut health series. Check out the first post, Signs of Good Digestion, to get a background on what’s normal and what isn’t when it comes to digestion.

How Does Leaky Gut Syndrome Impact Gut Health?

In this post, I will answer a few questions that you may have been asking yourself or ones that your coaching clients have come to you with.

  • What is leaky gut?

  • Why is a leaky gut a bad thing?

  • What can potentially cause leaky gut syndrome?

  • How can you improve a leaky gut?

By the end of this article, you’ll have a better understanding of gut health, how bacteria in the gut impact your overall health, and how you can improve gut health naturally.

Having good gut health can impact mental health, so you should work to improve your gut health.

What is Leaky Gut Syndrome?

Leaky gut, often referred to as “increased intestinal permeability” in scientific literature, is a condition that refers to a compromised barrier in the lining of the intestines. In a healthy gut, the intestinal lining acts as a selective barrier, allowing nutrients to be absorbed while preventing harmful substances from entering the bloodstream. However, in leaky gut syndrome, the intestinal lining becomes more permeable, allowing toxins, undigested food particles, and bacteria to leak through the intestinal wall and enter the bloodstream.

This leakage triggers an immune response, leading to inflammation and potential health issues. The immune system may recognize these foreign substances as threats, potentially causing a wide range of symptoms and contributing to various health conditions. Leaky gut syndrome has been associated with digestive disorders, autoimmune diseases, allergies, skin conditions, mood disorders, and more.

But not everyone in the fitness space agrees on this.

If you follow some of the more zealous health gurus on the internet, a lot of them talk about leaky gut as if it’s this brand new finding that is the cause of all your health issues, why your father-in-law doesn’t like you, and probably why your dog ran away too. At least, that’s the type of fervor many people talk about it with.

A lot of these types of gurus are the reason the opposite side has surfaced; those completely writing off leaky gut, saying it’s unscientific and doesn’t exist.

The only thing unscientific about leaky gut syndrome is the term. Leaky gut certainly does exist, although it’s more formally known as increased intestinal permeability or intestinal barrier dysfunction within the scientific literature.

What is Normal for Gut Health?

To fully understand leaky gut, you should first understand that intestinal permeability is a normal phenomenon for everyone. It’s only when permeability is highly increased and gets a little out of control that it becomes problematic. 

Before we get ahead of ourselves, let’s talk a bit about basic digestion.

First, food goes through digestive processes in the mouth with your teeth and saliva, and then the stomach with acid and enzymes. From there, it goes to the digestive tract, specifically the small intestine, which is where most absorption occurs.

Some things in food are absorbed by going into or through the actual intestinal cells, and some things are absorbed by going between the cellular space (permeability). When we’re talking about leaky gut, we’re mainly looking at what’s going between the cells. 

There are sets of proteins in between intestinal cells that regulate intestinal permeability very carefully, so when food is consumed, these proteins relax a little bit, increasing intestinal permeability slightly so that certain molecules can be absorbed, and after absorption is complete, they tighten up again.

This normal level of intestinal permeability was actually found and precisely defined by the consensus of an expert panel in Frankfurt, Germany in June 2012. 

Seeing a doctor can help you ensure you have healthy gut bacteria.

When does this become an issue?

If your gut health is suboptimal, you may experience more permeability than is considered normal.

When your intestine becomes too permeable, it becomes pathological, which means nutrient absorption is deregulated in some way, shape, or form, and the space in between intestinal cells is open more than it should be, more often than it should be. Hence the term, leaky gut syndrome.

Leaky gut syndrome is quite problematic for overall health. The thing that caused the permeability function to break down probably isn’t doing the rest of your body any favors. We’ll dive into root causes in a little bit, but gut barrier dysfunction only really occurs when health is a lot less than optimal. 

Once gut health deteriorates and intestinal permeability increases, however, things we don’t want can get into the bloodstream and circulation. 

Undigested Protein in the Bloodstream

One key example of something we don’t want in the bloodstream would be proteins that haven’t been fully digested. If you have increased intestinal permeability, there’s a good chance you have compromised digestion a bit further up the chain as well. It could be lower stomach acid or less enzyme secretion, which can result in proteins that don’t get fully broken down into their appropriate amino acids. 

Normally, things like undigested proteins would pass right through the small intestine and either get fermented by large intestinal bacteria or pass through in feces, but in the presence of leaky gut syndrome, these proteins can get into the bloodstream.

This is an issue because our bodies are used to seeing the individual components of these things in the bloodstream; amino acids from proteins, simple sugars from more complex carbs, etc.

If a portion of an undigested protein makes its way through and into the bloodstream, the immune system basically recognizes it as a foreign invader and attacks it, causing inflammation (as inflammation is just the activation of the immune system). 

After a bit of time, the immune system can create antibodies to these foods, which is one way you can develop dietary sensitivities or food allergies. You might have heard it’s possible to get dietary sensitivities to foods you eat over and over and this is one way that that can happen. The good news is, these are “false” food sensitivities that will go away once the gut heals.

*Note that not all dietary sensitivities develop this way, so you may still have some sensitivities that exist after you improve your gut health and stop the leaky gut. 

Bacteria in the Bloodstream

There are also consequences of having bacteria in the bloodstream.

The next example, and the real issue when it comes to systemic inflammation, would be components of bacteria that reside within the intestine.

There are little pieces of bacterial cell walls called LPS or endotoxin and, in the presence of increased permeability, these bacterial cells will make it from the intestine into the bloodstream in large amounts. LPS is widely known to be an enormous inducer of inflammation and oxidative stress, which could contribute to the development of numerous chronic diseases.

We know that both elevated levels of LPS and increased intestinal permeability are present in many conditions: irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) including Crohn’s disease and Colitis, alcoholic and non-alcoholic liver disease, type 1 and 2 diabetes, chronic depression, obsessive-compulsive disorder, multiple sclerosis, lupus, and many other autoimmune diseases. 

In some cases, increased intestinal permeability comes before the disease condition, in other cases, it seems that the condition is causing the increased intestinal permeability. The small details of which happens first haven’t been fully hashed out for many of the conditions. 

What Causes Leaky Gut?

There are several factors that can impact your gut health, some of which are easier to address than others.

Gut barrier dysfunction also known as leaky gut. Text: causes: poor diet, food sensitivities, stress, NSAIDs, overconsumption of alcohol, smoking, poor sleep, obesity, chronic high blood sugar toxins. Image of intestinal barrier showing bacteria getting through permiated intestine.

Stress and Gut Health

Psychological stress, for one, can certainly contribute to gut health issues such as leaky gut.

If something is coming in dietarily that is causing the gut barrier to break down, normally the immune system rushes in to repair these types of things. However, under chronic stress, the immune system is significantly downregulated and shows a shift in behavior in general, so the damage being caused to the intestinal barrier is outpacing the immune system’s ability to heal it. There are many other ways stress contributes to gut health and overall health, but we won’t dive into them so much here. 

Poor Diet Impacts Gut Health

The obvious elephant in the room, and also one of the biggest causes is a poor diet.

Processed foods contain numerous additives which have been shown to irritate the gut lining and gut bacteria over time. Large boluses of fructose (amounts you’d see in high fructose corn syrup-sweetened beverages, not the amounts you’d see in whole fruit) have been shown to increase gut irritation. 

Western-diet-style meals containing large amounts of saturated fat with simple sugars can cause this as well. Hyperglycemia, or chronic high blood sugar, is one of the most established causes of increased intestinal permeability that’s been seen over and over in studies, even independently of body fat levels. 

As we know, a poor diet can result in other conditions like metabolic disease or cardiovascular disease, and the chronic low-grade inflammation from these can potentially be taking immune system resources away from repairing the gut.

Gliadin, a component of gluten, causes increased permeability in everyone, but for some normal amounts don’t cause issues, and for others, it leads to medical and health issues.

Alcohol in anything more than moderate amounts contributes over time as well.

There are a lot more components to this. 

Dysbiosis (aka Gut Bacteria)

A healthy microbiome is actually a very strong regulator of intestinal permeability. A healthy microbiome creates short-chain fatty acids, which contribute to the gut’s mucus layer, protecting it from irritation and other things that could potentially cause increased permeability. 

Some bacteria in a healthy gut actually directly upregulate the amounts of the proteins that are responsible for these tight junctions between the cells. There are an incredibly large amount of metabolites that healthy gut bacteria produce that contribute to a healthy gut lining as well; these are called post-biotics. 

Medication and Gut Health

Finally, drugs can also impact gut health and contribute to a leaky gut.

NSAIDS, steroid medications, oral birth control, Motrin, aspirin, and other less common medications could contribute to intestinal permeability. 

How to Fix Leaky Gut

Gut barrier dysfunction (aka leaky gut syndrome) solutions. Image of intestine and text that says healthy, fiber rich diet arrow pointing to text that says beneficial gut microbiota leads to microbial metabolites

I’ll caveat this with the fact that going into a detailed gut protocol is out of the scope of this blog post, but let’s give some tips and considerations. 

First, if the person is obese or overweight and has glycemic dysregulation, you probably shouldn’t worry about targeting the gut first with an elimination protocol. Focus on getting rid of their metabolic issues through general lifestyle optimization through increased food quality (lower percentage of processed foods), weight loss, strength training, lots of movement, quality sleep, reduced stress, etc. In many cases, this can get rid of leaky gut without targeting it specifically.

If someone’s not obese, still focusing on the basics like getting enough fiber from diverse sources, including fermented foods, making sure they’re getting enough hydration, and ensuring the vast majority of their food choices are from whole foods can certainly help.

If they have good blood sugar regulation, are a healthy body fat percentage, are eating mostly whole foods, and aren’t under-eating or chronically under-eating, then we may be looking at an elimination protocol, which we go very in-depth about in our Functional Nutrition and Metabolism Specialization course. 

Check out my other gut health posts to dive deeper into this topic and learn how to improve overall health by addressing your gut:


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