For decades, Leaky gut was considered a theory, something people thought was going on but couldn’t prove. Now, after many years, we have a lot of evidence leaky gut is real, and contributes to a wide range of conditions, including autoimmune disease.
The research into leaky gut is growing at an alarming rate, which proves it’s a significant factor. Over the past 35 years, more than 2000 scientific publications have been released. From 10 publications per year 35 years ago to now over 100 per year .
We know a lot, but still, not every aspect of this phenomenon is fully understood.
What is Leaky Gut?
The medical term for leaky gut is intestinal permeability.
Basically, what happens is things can leak through the intestinal wall that shouldn’t be able to.
The video below encompasses the general concept.
The Healthy Intestinal Barrier
We have a sophisticated gastrointestinal system, and the mucosal barrier is responsible for digestion and absorption. The mucosal barrier is supposed to be selective; only allowing certain things from our digestive tract into our bodies.
Not only is our gut lining exposed to absorbable nutrients, but also food antigens, commensal bacteria, pathogens and toxins . As such, we have a complex system protecting us.
There are a few components in our guts protecting bad things from getting absorbed into our blood stream:
- Physical barrier: cellular component consisting of blood vessels, epithelial cell lining and mucus layer 
- Next to physical barrier we have chemical substances: digestive secretions, immune molecules, cell products like cytokines, inflammatory mediators, antimicrobial peptides
- The microbiota is involved in metabolic processes, and modulates the barrier, but is not a barrier itself 
Impressively – the front line of this barrier is maintained by a single layer of specialized epithelial cells that are linked together by tiny proteins called tight junctions.
All of these layers of protection are vital to protect against leaky gut.
Mechanisms of Leaky Gut
Diet induced leakiness
- Many dietary factors alter the gut microbiota
- Vitamin D (deficiency)
- Recognized to protect against intestinal permeability 
- Low fiber diet shown to trigger mucus-degrading bacteria 
- Western-style diet
- High in fat, carbs, protein. Associated with excess amounts of circulating bacterial toxins.
- Associated with systemic inflammation, metabolic syndrome 
- We also see higher consumption of fructose in the western diet: high fructose consumption also associated with loss of tight junction proteins 
- Vitamin D (deficiency)
Stress-induced gut leakiness
- Burn injuries: a lot of proteins throughout the body are relocated – including those from the gut 
- Mainly chronic consumption; is responsible for barrier dysfunction, alterations in quality and quantity of gut microbiota and bacterial toxin translocation
- Much of the changes to intestinal permeability are related to changes in the gut flora.
- Some bacteria can produce alcohol such as E.coli and Weissella (which is one way these bugs can compromise the intestinal barrier)
- H pylori (a gram negative bacterium)
- Directly increases epithelial permeability by redistributing proteins 
Oxidative stress 
Proinflammatory cytokines 
Altered intramucosal pH 
Leaky gut is a well known phenomenon. Our guts are supposed to absorb certain nutrients from our food and exclude certain toxins, antigens and bacteria.
If the gut lining is harmed in any way, it results in leaky gut; also known as intestinal permeability. Future posts will highlight exactly how leaky gut can contribute to autoimmune disease.