What causes leaky gut?
'Leaky gut' is a term you've probably heard of - it's a huge area of research. Yet like many things, there's also lots of misinformation around about it!!
Leaky gut is called intestinal permeability in the science world - it means a digestive system that allows things into the blood stream that should not be there
It's been linked to various diseases including :
✔️ irritable bowel ( people with IBS have significantly higher rates)
✔️ inflammatory bowel disease ( often precedes this by years, and is thought to potentially be a trigger)
✔️ type 2 diabetes, metabolic disease
✔️ neuro degenerative disease such as parkinsons and alzheimers
✔️ autoimmune disease
✔️ multiple sclerosis
✔️ allergies
✔️ arthritis
✔️ liver disease ie fatty liver
✔️mood disorders ie depression and anxiety
✔️ageing (due to a process called ‘inflammaging’)
In some of these, evidence is limited ie people with the disease have higher rates of leaky gut but we don't know if the leaky gut causes it - research is ongoing. In others the science is much clearer. As with many things in health, leaky gut isn't usually the sole cause of illnesses - but it's thought to play a significant role in many.
A healthy gut is made up of several layers :
✔️ two mucus layers (a loose outer layer where bacteria live, and a tight inner layer that covers gut cells)
✔️Our gut microbiota (the microorganisms that inhabit our digestive tract), which live near the mucus layer, crowding out unfamiliar microbes.
✔️ antibacterial proteins and IgA secreted by gut immune cells (paneth cells) that defend against microbes and toxins
✔️ epithelial cells (gut cells) that are normally tightly connected
✔️ lamina propria (inner layer), that contains nerve and immune cells
In a healthy gut, the mucus layers and cell junctions stop or limit bacteria and bacterial toxins from getting into the blood stream.
This layer, referred to as the intestinal epithelium, must be permeable to nutrients yet impermeable to pathogens. Ie it lets us absorb nutrients from our food, but stops the bad stuff getting through
The gut wall creates a barrier between gut contents and the rest of the body - as most molecules in our gut are ‘foreign’ to our body, and need to be kept away from our immune cells, to avoid triggering an immune reaction.
However if the mucus layer is damaged, or the cell junctions become 'leaky', byproducts from digestion such as lipopolysaccharide (LPS) can get into the circulation and travel to other parts of the body, such as our liver, brain, fat cells, arteries, and muscle
These can trigger an inflammatory response in these tissues, which may then trigger off the development of other diseases.
Gut wall damage from coeliac disease, gut infections, and IBD also cause 'leakage' but they are not technically leaky gut (as they are due to cell damage rather than leaky junctions)
Leaky gut can occur from :
✔️ high fat Western diets (note whole food ketogenic diets may not have the same effect)
✔️ gut infections
✔️ altered gut microbiome
✔️ physical or emotional stress
✔️ pregnancy
✔️ NSAID drugs
✔️ dietary emulsifiers
✔️ high blood sugars, and potentially high sugar diets
We'll cover what to do about leaky gut in a separate post - please check it out if you'd like to know more 😊
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