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The gut immune connection

Gut Immune Connection

Main functions of the Immune System

The immune system protects our body from foreign substances, cells and tissues, and includes the thymus, spleen, lymph nodes, and special lymphoid tissue found in the gastrointestinal tract and bone marrow. It is an internal communication system, made up of networks of integrated cells, which are there to protect our body.

A good analogy is to imagine the human immune system as an entire military force in place ready to recognise, attack and destroy any "invaders" in order to preserve health.

The immune system has three main functions, these are to:

  • Identify foreign substances such as bacteria, viruses, parasites and chemical toxins.
  • Destroy each specific type of foreign substance (one plan of attack does not apply to all invaders).
  • Maintain a "built-in" memory to recall the specific type of invader next time it enters the body.When the immune system is not able to differentiate between the host (you) and an invader it may begin to destroy healthy cells and tissues in our body. This is referred to as an autoimmune disorder.

Previously we posted an article that discussed the strong link between our gut and the brain (The Gut Brain Connection). This mentioned the enteric nervous system (ENS), which is imbedded in the lining of the gastrointestinal tract, and how it has a complex interaction with the gut and the immune system.

The gastrointestinal associated lymph tissue is the largest immune compartment in the body. Many people do not realise that approximately 80% of our immune system is located in our digestive system, which explains why it is vital to maintain a healthy gut to ensure optimal health.


Maintain a healthy gastrointestinal tract through gut flora

A vital component of a healthy gastrointestinal tract is gut flora. The normal bacterial population in the human gut is equal to the total number of cells in our entire body.

This complex "army" of bacteria is made up of more than twenty trillion cells. Dr. Natasha Campbell-McBride MD, MMedSci (neurology), MMedSci(nutrition), explains in her book (Gut and Psycholgy Syndrome) how the “essential or beneficial bacteria in our digestive system engage a very important member of the immune system – the lymphoid tissue of the gut wall – and take part in the production of huge numbers of lymphocytes and (therefore the production of) immunoglobulins.”

These are key elements of the immune system. She also writes how scientific research has shown that people with damaged gut flora have far fewer lymphocytes in their gut wall, which leaves it (and therefore the rest of their body) poorly protected from any invaders.

When there is a deficiency of beneficial bacteria in the gut, lymphocytes are not the only immune cells that are compromised; macrophages and neutrophils, which gather in inflamed and infected tissues and clean them up by engulfing and destroying viruses, toxins, bacteria and cellular debris, are not able to carry out their job properly either.

Healthy gut flora also plays a vital role in the production of many other active regulators of the immune response.


Gut flora health has an influence beyond the gut itself

Dr. Natasha Campbell-McBride believes the influence of our gut flora on the immune system reaches far beyond the gut itself. With research showing that damaged gut flora can not only cause the levels of lymphocytes, macrophages, interferons, cytokines, IgA, etc. in the digestive system to drop but the whole immune system in the body to get out of balance.

Abnormal gut flora can also cause the gastrointestinal wall to become damaged and “leaky”, which may result in a stream of invaders and undigested food coming through the damaged barriers of the gut and into the bloodstream. This will place additional strain on an already compromised immune system (please see my previous newsletter on Leaky Gut Syndrome for more information on this topic).


The immune system needs constant nourishment

The immune system cannot function without constant nourishment; it requires most known vitamins and minerals, fats and amino acids to be able to do its job properly.

Some of the key areas in our daily lives which may have a detrimental effect on the immune system are:

  • A lack of healthy (preferably) organic whole food to nourish immune protection.
  • An incorrect balance of fats, carbohydrates and proteins in our diet.
  • Being subjected to excessive, prolonged stress (whether it be physical, emotional or psychological). This will eventually manifest as a stressed immune system unable to provide maximum protection. It's been likened to depleting the army's ammunition little by little, and then when it's needed for a battle, little, if any, remains to be used for defence.
  • Intestinal toxicity; this can exceed the liver's ability to neutralise toxins, potentially causing autointoxication, toxaemia and immune system disorders.
  • Excess consumption of alcohol and/or prescription drugs – specifically antibiotics, which attack the "good" and "bad" bacteria, and leave the host vulnerable when an invasion occurs, especially to infections like yeast.

There is also an intimate connection between our gut and the liver through the hepatic portal vein; however this is a big topic for another blog article.



As stated in previous articles, most biomedical practitioners will agree that cleaning up the gut is the first priority in the treatment of many conditions. If you do not clean up the gut, the rest of the healing effort will be more complicated and less effective.

Jon Pangborn (PhD) and Sidney Macdonald Baker (MD) go as far to say... “be wary of any report you read about this or that treatment that has not worked in children with autism, if the researchers have failed to address gut issues first”.

We have a wide range of probiotics available at Kingsway Compounding. As well as prebiotics and many other supplements which have demonstrated an ability to help support gut health.


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