Is leaky gut real?

If you'd asked most doctors 10 years ago about ‘leaky gut’, the resounding response would be 'it doesn't exist'.

Yet like many things, we've since discovered it actually DOES exist - just in a different way to how we thought. And it plays a huge role in immunity and general health.

While the science is still emerging, and we don't have super clear links providing that leaky gut is responsible for all the things attributed to it, there is certainly enough research out there showing it does play and important role in areas such as inflammation, allergy risk, heart and brain health, and autoimmune disease - and this research is growing rapidly. Try typing ‘intestinal permeability ‘into a pubmed search and you'll see what we mean!!

So how does it work?

In a healthy gut, the intestinal contents (food, microbes) stay fairly separate to the rest of the body, due to the gut wall cells providing a barrier between them.

However gut wall is very thin- just one cell thick in some places- and is connected by ‘tight junctions’ that open up to let let nutrients into the body (when we digest food) , and keep germs and toxins out.

Overlying this wall is a coating of mucin, which contains antimicrobial compounds and protects the gut wall cells, keeping them intact and healthy, and reducing inflammation.

The outside of the gut wall is also lined with immune cells (gut associated lymphoid tissue, or GALT) - they actually make up 70% of the entire immune system!! These cells play a key role in ‘training our immune system, via detecting microbes, harmful substances, and allergens in our food

The bacteria in our gut (microbes) are introduced at birth via a vaginal delivery, are promoted by compounds in breast milk (human oligosaccharides) , and are influenced throughout the rest of our life in response to diet, stress, antibiotics etc.

There are 'good' and 'bad' strains - the good ones help the immune system, and reduce inflammation, among many other roles.

Good bacteria also produce short chain fatty acids (SCFA) - one called butyrate  is the main energy source for the gut wall, and helps create mucin and the proteins required to form tight gut junctions - see our posts on butyrate and fibre for more details.

When the balance of bacteria shifts to more 'bad' bacteria, this does several things :

✔️increases inflammation

✔️damages the gut lining

✔️alters immune function

The tight junctions between gut cells then ‘loosen’, and by-products of digestion and metabolism 'leak' into the body, triggering inflammation, allergy, and contributing to the health issues mentioned above, among others.

This is detected in our blood stream via lipopolysaccharides (LPA), although at present testing for these is largely limited to clinical trials (ie its not something you can reliably test for on a blood test - although this may change in future)

And our diet has a HUGE impact on this - with diets high in saturated fat, refined carbohydrates, added sugar, omega 6 and red meat, and low in fibre (aka the typical ‘Western diet’) promoting gut inflammation and 'leaky gut', as well as stimulating the growth of ‘bad ‘bacteria

Emulsifiers in processed food such as CMC, maltodextrin and polysorbate also promote gut inflammation and gut wall permeability. Artificial sweeteners may have a similar effect, although the science on this is less clear

And all of these factors play a major role in autoimmune disease, allergy, and  inflammation!

A gut healthy diet:

✔️is  high in plant foods (fibre, prebiotics, polyphenols), omega 3 and citrus

✔️is low in saturated fat /added sugar/red meat /alcohol, processed food

-✔️has adequate protein and fat soluble vitamins

✔️includes probiotics such as fermented foods

Lack of sleep, stress, excessive exercise (without adequate rest breaks) and alcohol can all also affect leaky gut and are part of the equation.

And time restricted eating (a period of at least 12 hours overnight with no calories) as well as avoiding snacking between meals may also help, as this both gives the gut cells time to ‘rest and repair’, and also promotes a healthier gut microbiome.

There is some evidence for supplements such as glutamine, zinc, and prebiotics o help improve ‘leaky gut’ as well, although these should be used in addition to lifestyle factors, rather than as a substitute for them.

So to reduce leaky gut, the advice is simple

Eat whole foods, mostly plants, not too much. And aim for a well balanced lifestyle.

Even small changes help!!