What is the Immune System?

May 19, 2020 3:23 pm Published by

There are different branches of our immune system.  About 70% of our immune system and their related cells are located within our digestive system, lining the mucosa of our gastro intestinal (GI) tract.The health of our digestive system plays a vital role in providing a healthy immune system.  

It relies heavily on an adequate supply of nutrients to function, especially for ramping up a heavy attack on viruses and bacteria.

Body defence

Our body has three lines of defence:-

  1. External barriers – skin, mucous membranes & the GI microbiome – ‘non-specific’
  2. Internal barriers.- fever, antimicrobial cells, inflammation & the GI microbiome – ‘non-specific’
  3. Internal barrier.   – immune system, cells & antibodies, & the GI microbiome – ‘specific’

The Innate immune system

This is our first line of defence against foreign invaders, we are born with this system.  It is an immediate response but does not involve a memory to an antigen. So the inflammatory reaction is immediate and ‘non-specific’, meaning all antigens are treated the same way.

An antigen is a foreign substance such as bacteria, viruses or toxins that cause an immune response in the body.

Our bodies come into contact with microbes and pathogens on a daily basis and all have the potential to trigger an immune response, this doesn’t necessarily mean we get sick or show symptoms. Our bodies respond by removing foreign particles by various methods:-

  • Skin sweating and natural exfoliation
  • Mucous lining our digestive tract and lungs
  • The cough reflex 
  • Hairs and mucous lining our nose, tears and saliva 
  • Stomach acid, 
  • Mild fever and inflammation
  • Sometimes even vomiting and diarrhoea

The Acquired Immune system

Also called the ‘specific’ or adaptive immune system, not present at birth, it must adapt itself and learn about encountered threats. This is our second line of defence activated by the innate system.  A ‘specific’ response is created and remembered after the pathogen has been eliminated, which means a faster and stronger attack can be mounted each time this pathogen is encountered.

For these serious threats we have an army of various immune cells waiting with different skills to mount a more intense attack if necessary.  Some of their actions involve:-

  • To engulf and destroy foreign invaders 
  • To release toxic chemicals 
  • To co-ordinate an immune response
  • Chemical messengers such as cytokines, to help cells communicate
  • To produce antibodies

So digestive system function is critical to good health. 

The best approach for support is a comprehensive plan:-

  • Diet
  • Lifestyle
  • Stress management 
  • Exercises
  • Nutritional supplementation
  • The use of plant based medicines

Now more than ever, health foods should be a top priority, mindful eating habits to reduce susceptibility to infections.  There is no doubt that the western diet (high in saturated fatty acids) activates our innate immune system, causing chronic inflammation and reduces our ability to fight off viral and bacterial pathogens.

At a minimum, getting our daily dose of vitamin C, D & zinc is necessary for our immune systems to function properly.








Pizzorno J, Murray M (2007). Textbook of natural medicine. 



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