Leaky Gut – the Importance of the Barrier Wall

Is your gut leaky? More accurately called increased intestinal permeability, this condition is often unsuspected but can have a profound effect on our health. In this article we’ll have a look at the importance of our digestive lining, and how to keep it in tip-top health.

Keeping the Outside, Outside

When we eat a meal, food passes along the digestive tract, firstly through our stomach and then along the small and large intestines. However, throughout the process of digestion the food technically remains outside our body until it is absorbed.

The lining of our digestive system provides a barrier between the inside of our body and what’s outside. It’s crucial this lining allows nutrients through into the bloodstream, at the same time preventing other less desirable substances gaining access to the body.

Incredibly, the digestive lining is only one cell thick. Between each cell are tiny gaps called ‘tight junctions’. It’s important these gaps are the correct size to allow nutrients and water molecules through while preventing harmful substances from being absorbed. If the tight junctions become too large, the result is increased intestinal permeability.

This means substances which should ideally be eliminated with our stool such as bacteria, viruses or toxins, or components of food which have been incompletely digested are instead absorbed into the bloodstream.

Leaky Gut Illustration

Leaky Gut Illustration

What causes leaky gut?

A lot of different factors associated with our modern lifestyles can damage the gut lining. These include medications such as non-steroidal anti-inflammatories and aspirin, stress, alcohol, bacterial infections, constipation and nutrient deficiencies, such as lack of zinc or vitamins A and D. Even stress can contribute to the development of leaky gut.

Some foods, particularly red meat, dairy products, sugar and processed foods can encourage inflammation throughout the body and irritate the gut lining.

A protein called zonulin produced by intestinal cells causes the gaps between the tight junctions to expand.

Initially it was believed tight junctions are either open or closed, but research shows they open and close in response to many factors such as our food choices and levels of inflammation in the body. Obesity has been found to increase zonulin secretion, as has the consumption of gluten grains.

This demonstrates the importance of lifestyle and nutrition choices on the proper functioning of our intestinal lining.

What Symptoms are Caused by Leaky Gut?

It’s hard to work out which symptoms are as a result of leaky gut or whether increased intestinal permeability is simply a symptom of a digestive system which is out of balance. What we do know, however, is leaky gut accompanies a long list of chronic health problems.

Leaky gut has been linked to the following:

  • IBS
  • Chronic fatigue and fibromyalgia
  • Depression and low mood
  • Headache and migraine
  • Thyroid problems
  • Skin conditions
  • Type 2 diabetes
  • Autism
  • Alzheimer’s disease
  • Parkinson’s disease

Functional medicine practitioners notice leaky gut is frequently connected with autoimmune diseases such as multiple sclerosis, lupus and rheumatoid arthritis. Research suggests it plays a role in the development of these conditions because it’s been seen prior to their development.

Leaky gut is associated with an increase in chronic inflammation throughout the body, as well as reduced absorption of vitamins and minerals.

Leaky Gut and Food Sensitivities

If tight junctions expand, particles of food which have not yet been completely digested may be able to pass through the digestive lining. These will be detected by the immune system and can be mistaken for unfamiliar invaders. If this happens the immune system may erroneously attack them. This is what happens when we develop food sensitivities.

In a vicious cycle, if we continue to eat foods to which we’re sensitive, ongoing stimulation of the immune system will cause it to release inflammatory chemicals which can result in further damage to the intestinal lining.

Leaky Gut and the Microbiome

The intestinal lining has an intimate relationship with the trillions of bacteria living in our gut, which are called the microbiome. If we have mainly friendly bacteria living in our gut, they will produce chemicals which keep the gut lining healthy. If our gut bacteria are not so friendly, they can cause inflammation in the gut lining.

Testing for a Leaky Gut

Having a leaky gut can produce many and varied symptoms, so Functional Medicine practitioners use tests to determine the health of the intestinal lining. For example, a blood test can detect antibodies to zonulin, while a stool test can reveal the health of your microbiome.

If you are concerned your gut lining may not be as healthy as it could be, a consultation with a Functional Medicine practitioner can assess your symptoms, health history, food choices and lifestyle, as well as recommending functional tests to assess your gut function.