Natural therapists have been talking about the concept of leaky gut for years, but now scientists are also investigating it and how dealing with the condition could hold the key to tackling other health problems – and even help you live longer…

By Helen Foster

Leaky gut – or increased intestinal permeability as it’s known in the medical world – is a situation where the lining of your gut doesn’t work as it should.

‘Your gut lining is made up of a single line of cells. It’s designed to let water and nutrients out of your gut, but keep pathogens and undigested food inside,’ explains nutritional therapist, Sarah Grant.

‘In leaky gut, the integrity of this lining is compromised. The gaps, called tight junctions, between cells open up, which allows items that shouldn’t enter your bloodstream to do so. If this happens, your immune system mounts a response to them that triggers inflammation in your body.’

Once upon a time, typing that paragraph as fact couldn’t have happened. ‘We didn’t have microscopes sensitive enough to look at the cellular layer at the level we needed,’ says Dr Alessio Fasano from the Mucosal Immunology and Biology Research Center at Massachusetts General Hospital and the world’s leading authority on the science of leaky gut.

‘Once we did, we realised the gut cells weren’t cemented directly to each other but that there was a space between them. And then we learned those spaces were more like doors that could open and close.’

‘Your gut lining is made up of a single line of cells. It’s designed to let water and nutrients out of your gut, but keep pathogens and undigested food inside.’

The leaky gut effect

In the year 2000, Dr Fasano found the key that opened the doors. A protein called zonulin, which is released in large quantities under certain stimuli, like changes in your gut microbiome.

From this point on, science has backed the theory of intestinal permeability. Even NASA started studying it in astronauts: in 2019, they discovered that the negative effect of gravity on the integrity of the gut barrier made even simple food poisoning bugs more dangerous in space.

But, while more experts now recognise that leaky gut can happen, they’re still arguing over its consequences. Specifically, whether conditions associated with leaky gut are triggered by it – or causing it.

There’s increasing evidence pointing toward the former, according to Dr Fasano. ‘Animal models have found that the inflammation triggered by leaky gut destroys cells. For example, the beta cells in the pancreas, which can lead to Type 1 diabetes,’ he tells us.

Constant inflammation may also lead the immune system to become hypervigilant. This might explain why leaky gut is linked to allergy or autoimmune problems, such as inflammatory bowel disease.

‘Inflammation triggered by leaky gut destroys cells. For example, the beta cells in the pancreas, which can lead to Type 1 diabetes.’

‘Leaky gut to be more linked to specific disease. It may even be one reason for the rapid growth in chronic inflammatory diseases in the western world.’

Leaky gut, IBS or coeliac?

Despite this knowledge, Dr Fasanostill doesn’t like the use of the phrase ‘leaky gut syndrome’. It refers to a spectrum of problems in otherwise healthy people linked to gut permeability.

Instead, he believes leaky gut to be more linked to specific diseases. It may even be one reason for the rapid growth in chronic inflammatory diseases in the western world.

He feels there’s credible evidence for a link to leaky gut in IBS (particularly diarrhoea-associated IBS), coeliac disease, Type 1 diabetes, inflammatory bowel disease, neurodegenerative disease and clinical depression.

And fascinatingly, Dr Fasano also suspects that leaky gut could play a role in how fast we age. ‘Gut barrier integrity falls with age. However, we also know that if you modify a fruit fly so that their gut barrier doesn’t break, their lifespan doubles. If we could do the same for humans, it could see us live to 160,’ he says.

Diagnosing leaky gut syndrome

The bad news is there’s no clear test for leaky gut. So, you can’t prove if it’s behind your health concerns – not yet anyway.

‘A nutritional therapist can get some clues from stool tests that measure levels of zonulin and inflammatory markers, alongside a full picture of someone’s symptoms and lifestyle. However, we can’t categorically state it to be a diagnosis,’ says nutritional therapist, Sarah.

Nor has it been proven that restoring gut function can treat the conditions potentially associated with leaky gut. However, the science is fast heading that way: an animal trial on Type 1 diabetes has shown promise.

Dr Fasano has also developed a treatment for coeliac disease, which is based on preventing the tight junctions from opening. This treatment is currently in its final stages of trials.

So, while we wait for the scientists to do their thing, there’s certainly no harm in looking at how you can protect your gut lining – just like it protects you.

6 ways to prevent leaky gut

While in some people the propensity to a leaky gut is genetic, it’s also believed that your lifestyle may play a role in its development. Here’s how to shore up your gut lining…

Get your vitamins and minerals

‘Deficiencies in vitamins A, D and zinc have been linked to leaky gut,’ says Sarah. Stock up on dairy products, fish and liver for your vitamin a hit, try shellfish and wholegrains for zinc, and fortified foods, oily fish, some mushrooms and sunlight for vitamin D.

Go for glutamine to prevent leaky gut

Supplements of this amino acid are part of the treatment protocol when doctors suspect leaky gut, but you can also increase levels in your diet for general protection. Skimmed milk, eggs, tofu and beef are good sources of glutamine.

leaky gut gluten

Consider your gluten intake

In people with genetic sensitivity to it, a protein in gluten causes the release of zonulin. This triggers the tight junctions to open.

This doesn’t mean everyone should give up gluten. However, if you have IBS or other digestive symptoms, it might be something to consider.

symptoms of hormone imbalance anxiety

Reduce stress to protect your gut

Stress can trigger the gut to leak. A fascinating study from the US even showed that couples in unhappy marriages have signs of a leaky gut in their bloodstream.

Manage your blood sugar

A study from researchers in Israel and France found that sustained high sugar levels in the blood actually reprogrammed the gut cells to become more permeable. Another reason why it’s a good idea to keep sugar levels in your diet low.

Eat a rainbow of fruit and vegetables

Serve at least seven differently coloured plant foods daily. ‘It’s my number one tip for gut health,’ says Sarah. ‘The bacteria of the gut thrive on diversity. When they eat fibres from plant foods, they produce a substance called butyrate. This plays a role in gut integrity.’

Plenty of veggies also increases fibre in the diet and the more fibre you eat, the thicker your gut lining.

Click here for more tips and expert advice on boosting your gut health!