Do we really need to be boosting our immune system?

There is a lot of information on social media at the moment promoting ways to build immunity to protect you from Covid 19. Taking vitamin pills, apple cider vinegar shots and gargling with hot water will not stop you from getting Covid 19 or any virus for the matter however there are things we can do to support a healthy functioning immune system. Before we look at the practical things we can do, let’s take a look at how the immune system works.

The Immune System

The immune system is a highly intricate and complex system which consists of organs, specialised cells and chemicals that monitor and fight pathogens. The immune system consists of antibodies, white blood cells, the lymphatic system, the spleen, the thymus, and bone marrow.

Our immune system works as a gate keeper, recording and monitoring every pathogen it comes come into contact with, by means of B- and T-lymphocytes, white blood cells known as memory cells. This occurs so that if these pathogens enter the body again, they are dealt with quickly and efficiently before they can cause severe damage to the body.

The immune system consists of the following:

White blood cells

White blood cells are the really important players in immune system defence. They are made in your bone marrow and are part of the lymphatic system.

White blood cells travel through the body searching for foreign invaders or pathogens such as bacteria, viruses, parasites and fungi. If pathogens are found the white blood cells launch an immune attack to keep these invaders at bay. White blood cells consist of B-cells, T-cells and natural killer lymphocyte cells and many other types of immune cells.


Antibodies recognise substances called antigens on the surface of the pathogen, or in the chemicals they produce, which mark the microbe or toxin as being foreign. The antibodies then tag these antigens for destruction. Many cells, proteins and chemicals are involved in this attack.

Complement system

The complement system is made up of proteins that complement the work carried out by the antibodies.

Lymphatic system

The lymphatic system is comprised of a network of lymphoid tissues and organs that help to rid the body of toxins, waste and unwanted materials and debris. The primary function of the lymphatic system is to transport lymphatic fluid, a fluid containing white blood cells or lymphocytes throughout the body.


The spleen is an organ that filters our blood by removing microbes and destroying old or damaged red blood cells. It also makes disease-fighting components of the immune system (including antibodies and lymphocytes).

Bone marrow

Bone marrow is the spongy tissue found inside your bones. Most blood cells are made in your bone marrow. This process is called haemopoiesis. Bone marrow produces red blood cells which our bodies need to transport oxygen, white blood cells to help fight infection, and platelets which help our blood clot.


The thymus filters and monitors the contents of our blood. It produces white blood cells called T-lymphocytes. The thymus shrinks with age.

Our immune system works closely with a diverse number of gut microbes to develop tolerance for beneficial microbes and to create cellular defences against pathogenic microbes. The immune system and the gut microbiota have a mutualistic relationship, communicating to support and regulate each other. The importance of this interaction is highlighted by the fact that 70 –80% of the body’s immune cells are found in the gut.

The Gut

The gut epithelial cells are found from the mouth to the anus and are the mission control centre for the gut ecosystem. The epithelial cells are stimulated by gut environmental factors particularly microbes which interact with the immune cells to modulate gut immune cell responses.

The lumen of the gastrointestinal tract could be considered as outside of the body and much of it is heavily populated with potentially pathogenic microorganisms. It is therefore important that the immune system establishes and maintains a strong presence at this mucosal boundary. The digestive tube is heavily laden with immune cells such as lymphocytes, macrophages and other cells that participate in immune responses.

GALT or Gut Associated Lymphoid tissue is the underlying immune network. The GI immune system is present in the mucosa and submucosa of the GI tract, but especially prominent in the oropharynx, tonsils, subjacent to the mucosa – Peyer's patches and appendix.

In addition to the GALT, lymph nodes that receive lymph draining from the gut (mesenteric nodes) and Kupffer cells (phagocytic cells in the liver) play important roles in protecting the body against invasion.

The body has several other ways to defend itself against microbes. These systems work in harmony with the immune system to help us stay fit and well.

Other defence systems of the body

The skin

The skin is an interface with the outside environment and is colonized by microorganisms such as bacteria, fungi, viruses and mites. The beneficial microbes found on the skin help to protect us by communicating with the billions of T cells found in the skin.

The lungs

Mucous in the lungs or phlegm traps foreign particles whilst small hairs (cilia) wave the mucous upwards so it can be coughed out. Deep breathing, regular exercise and not smoking helps to keep the lungs healthy.

Body fluids

Sebum, saliva and tears contain anti-bacterial enzymes that help reduce the risk of infection. Staying hydrated and keeping up fluid intake is therefore important.

There is no single vitamin or mineral that will magically strengthen the immune system. In order for all the intricate systems of the body to be working effectively we need to ensure that our diet has the right amount of healthy nutrients. We need to include foods rich in healthy fats, proteins, fibre, antioxidants, vitamins particularly vitamin A, vitamin B6, folate, vitamin B12, vitamin C, vitamin E, vitamin D and minerals particularly zinc, selenium, magnesium and iron. Specific phytonutrients found in plant foods help the body to switch on its own cellular defence systems by natural gene expression, antioxidant cell production and by down regulating pro inflammatory pathways. If we are low in specific nutrients this could compromise our immune system. Likewise if our gut microbes are out of balance and we have an increase in pathogenic bacteria and compromised enterocyte cell function this will also influence the immune system response and may affect our ability to be able to efficiently deal with viruses, colds and flu.

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