The intestinal cells, just one cell layer thick, act as a physical barrier, as you can see in the middle part of the picture with the cells (in green, yellow, orange, blue) lined up against each other. Where the cells contact is sealed by tight junctions, only opening up to let things through that are needed by the body. Cells in the barrier also produce mucus (the blue wavy part of the picture) which essentially separates the cell layer from the gut lumen (where the food and other things like microbes are passing through) and provides extra physical protection. However it’ll also contain the immune antibody IgA, bile acids and other antimicrobial proteins, which further protects the gut lining from harmful microbes.
Underneath the cell layer, you have the lamina propria which contains further immune cells.
Then there are the protective microbes on the gut lumen side of the cell layer which can help prevent the colonisation of the more harmful ones and subsequent inflammation.
The immune setup has a special relationship with the protective microbes whereby it recognises them as being friendly and so does not react to them.

This whole mechanism, when working well, protects the body from potentially harmful substances, only allowing things like nutrients in, past the immune layers, and into circulation past the lamina propria.

But when not working optimally, things start seeping through that shouldn’t, and this is known as leaky gut.

As you can see in the upper portion of the picture, there is a gap between 2 green cells, with microbes (protective or harmful) and their toxic products like LPS, leaking through and getting into the circulation. This can then lead to local and widespread inflammation and damage to tissues in the body. But it’s not just microbes that could leak through. Undigested food and chemicals/pesticides could too.

There is something called molecular mimicry. In this, protein chains (be it from bacteria or undigested food e.g. dairy or gluten) that are leaking through set off the immune response (it’s important to note that protein chains should not be leaking through, but rather in the case of food at least, the digestive system needs to break down the protein chains into it’s amino acid constituents, which can then be safely absorbed). Now, these protein chains may look similar to a certain part of the body, e.g. the joints, or the thyroid. And now that the immune system has attacked this leaked protein chain, it can recognise one’s own similar looking protein chains in the body as foreign too, thus attacking them, causing inflammation and damage, and an autoimmune reaction!

So, if a leaky gut can be seen as a root cause for Ads, wouldn’t it make sense to address this?

So what can cause a leaky gut?….

WHAT WE CONSUME!
Low fibre diets (and higher processed and higher fat diets) can contribute to a leaky gut. Alcohol can kill good microbes (we use it medicine to kill microbes on our hands and surgical instruments!)! Then there’s other things like caffeine, soft drinks (sugar, but also sweeteners too have been shown to affect the good microbes!) and chlorinated water (remember, chlorine is also used to kill microbes!).
Our foods now also contain pesticides, herbicides, fungicides etc, with the purpose of killing and preventing microbes from growing on our food (ever seen those loaves of bread lasting weeks?!). Well guess what, they’ll also affect our beneficial and protective microbes!
All of these factors can impact on the level of protective and harmful microbes, thus compromising the intestinal defences.
Note that gluten may cause transient leaky gut normally, but it’s important to note that the vast majority of people are able to consume wheat/gluten without issue.

And then there’s antibiotics. Now antibiotics can be lifesaving, however, antibiotics don’t just target the intruder… they also kill the beneficial microbes too! Thus this can allow the more harmful bacteria to proliferate and cause inflammation.
This doesn’t mean you should never have antibiotics though. Of course when they are really necessary that’s fine. But otherwise we shouldn’t take antibiotics “just in case”.

STRESS
Stress is another factor that can cause a leaky gut. Our ancestors, when faced by a lion, needed to get into survival mode, and quick! This meant turning on the fight or flight response, leading to more blood going to the limbs and heart for obvious reasons – to run or fight! And so it made survival sense for blood not to flow to the digestive tract during such a scenario, so that it can be redistributed.
Well today, even though we don’t have a lion chasing us, we have a metaphorical lion on our back all the time with all the stressors we face with our modern lives. And the survival functions of the body have not changed, meaning that there is less blood flowing to our digestive tract due to the constant low grade fight or flight. And so this can compromise ones gut, from digestion to defence.

What are the symptoms of leaky gut?
Well, the symptoms of leaky gut could be the AD, but there may be other symptoms such as bloating, abdominal pains, diarrhoea, fatigue, food intolerances and allergies etc.

Can leaky gut be tested for?
Yes – there are sugar absorption tests, tight junction tests, and tests to measure bacterial toxins such as LPS.
Also a comprehensive stool analysis can be carried out to see if there is in imbalance (dysbiosis) in beneficial microbes, and if there is an overgrowth of harmful ones.

So is there anything that we can do to fix a leaky gut? YES!
Now every case will be different, but a general guide is the 5R protocol:

REMOVE the things that are causing an inflamed and leaky gut e.g. sugar, alcohol, wheat/gluten, animal products (as they are generally inflammatory and contain lots of antibiotics) harmful microbes

REPLACE digestive factors such as stomach acid, digestive enzymes (more on these things in another post)

REINOCULATE to bring back in the good microbes through probiotics. Allow them to thrive by feeding them the food they need – prebiotics. Prebiotics are found in fibre rich foods. Prebiotics are used by the beneficial microbes to make protective substances such as short chain fatty acids, which is an energy source for the intestinal barrier, allowing it to stay strong and intact. Short chain fatty acids also help to keep the gut immune system calm against protective microbes, recognising them as friends, thus allowing them to continue to thrive.

REPAIR the gut lining. There are many things that can help this e.g. glutamine, quercetin, prebiotics and other nutrients

REBALANCE the whole system in order to maintain gut health in the long term and prevent recurrence. This means eating right. We know that a high fibre, whole food plant based diet is highly beneficial and protective for the body. This includes fruits, vegetables, whole grains, legumes, nuts, seeds, herbs, spices, mushrooms. It can help populate the gut with those beneficial microbes and help to ensure a strong and intact gut lining. There are cases of ADs even reversing on a whole food plant based diet, as well as other chronic diseases, intolerances, allergies. Animal and processed foods on the other hand are linked to so many diseases. Clean drinking water is a necessity (tap water is not clean!), with the removal of chlorine being important. So buying a good quality water filter is worthwhile. Reducing caffeine and omitting alcohol also. And with the healing of the gut lining, wheat/gluten may be able to be brought back in.