Immune health
What is the immune system?
Our immune system is a complex network of organs, cells and chemicals that work together to protect our body from infection. Without an immune system, we would be vulnerable to a host of bacteria, viruses, fungi and parasites that could potentially threaten our life.
A healthy immune system can distinguish our tissue from foreign tissue. If it comes into contact with a pathogen (organism that causes disease), it mounts an immune response to fight off this threat.
Immune systems that don’t work properly (i.e. underactive or overactive immune systems) or that are affected by chronic health conditions, can lead to health problems. Taking care of our immune health is vital to keep our body healthy and strong.
Parts of the immune system
Many parts of the body make up our immune system and each one has an important role to play in protecting our health. The immune system is made up of:
Skin —Our body’s first line of defence as it helps prevent pathogens from entering our body.
Bone marrow — Our immune cells are made in our bone marrow.
Thymus — This is a gland in the upper chest where some immune cells mature.
White blood cells — Also called leukocytes, white blood cells move through our body looking for microbes such as bacteria, viruses, and fungi. There are many types of white blood cells, each with its own purpose. They include lymphocytes, such as B-cells and T-cells. If white blood cells come across harmful microbes (or bacteria), they launch an immune attack to fight them to keep us healthy.
Antibodies — An antibody is a protein component of the immune system that neutralises antigens (the protein component of bacteria, viruses and fungi). Once we have been exposed to a foreign substance, antibodies continue to circulate and provide protection against future exposures to that antigen.
Lymphatic system — This is a network of tiny vessels that allow immune cells to travel between tissues and blood cells.
Lymph nodes — Also called lymph glands, these small lumps are found in our groin, neck, armpit and other areas of our body. They contain immune cells that analyse the pathogens in our body and are responsible for sending off the specific white blood cells to fight off the pathogen.
Spleen — Our spleen filters blood, removes microbes and destroys old or damaged red blood cells. It also makes important components of our immune system including antibodies.
Tonsils and adenoids — These are located in the throat and nasal passages and play an important role in trapping pathogens as soon as they enter our body. They have immune cells which help protect us from throat and lung infections.
Mucous membranes — These membranes line the respiratory, digestive, urinary and reproductive tracts. Mucous membranes produce mucous. This mucous either traps germs (in the case of the respiratory tract) or contains antibodies to kill microbes.
Stomach and bowel — Stomach acid can kill many bacteria if they enter, while good bacteria in our bowels (intestines) can kill harmful bacteria. Lining the mucous membrane of the small intestine is what’s known as ‘Peyer’s Patches’- groupings of lymphoid follicles which play an important role in monitoring for potential pathogens in your digestive system.
How does the immune system work?
When harmful pathogens enter our body, the immune system launches an ‘attack’ called an immune response, to help fight this invasion. White blood cells identify the pathogen, antibodies are released to fight it, and other immune responses such as fever and inflammation may occur.
A rise in body temperature (fever) is designed to kill some microbes, as well as trigger the body’s repair processes. When inflammation occurs, damaged cells release chemicals including histamines, which cause blood vessels to leak fluid into the tissues causing swelling. This swelling helps prevent pathogens from having further contact with the body’s tissues.
What is immunity?
There are three types of immunity. These are:
Innate immunity
These are the defence systems that we are born with. Examples include:
o skin
o stomach acid
o mucous
o the cough reflex
o enzymes in tears and skin
Acquired immunity
This is the type of immunity we develop when we’re exposed to various antigens. Once our body has come into contact with an antigen for the first time, it usually stores information about it and how to fight it. When it recognises the antigens again, our body can fight them straight away. We can acquire immunity through:
o vaccines
o exposure to an infection or disease
Passive immunity
This is temporary immunity we gain due to antibodies produced by another body other than our own. An example of this is babies being born with antibodies that were transferred through the placenta from their mother.
What are the signs of a weak immune system?
The primary symptom of a weak immune system is increased susceptibility to illness or infection. Someone who is immunocompromised (has a weakened immune system) may get infections more frequently than most people, or their illnesses may be more severe or harder to treat. Signs of a weak immune system include:
frequent colds and other infections such as pneumonia and bronchitis
digestive problems such as frequent diarrhoea, constipation or bloating
wounds that take longer than normal to heal
fatigue
skin infections
delayed growth and development
autoimmune disorders
What causes a weak immune system?
Several factors can cause a weakened immune system. These include8:
smoking
drinking alcohol
poor nutrition
stress
obesity
aging
medical conditions such as HIV, diabetes, cancer and recent serious infections
medications such as steroids or chemotherapy
What about immune system disorders?
Sometimes there can be problems with our immune system that means it doesn’t work as it should. These are classified as immune system disorders and there are four categories9:
1. Primary immune deficiency— being born with a weak immune system
2. Autoimmune disease— this is when our immune system attacks normal healthy tissue in our bodies. Examples include:
type 1 diabetes
rheumatoid arthritis
inflammatory bowel disease
multiple sclerosis
lupus
Guillian-Barre syndrome
psoriasis
Graves’ disease
Hashimoto’s thyroiditis
3. Acquired immune deficiency— getting a disease that weakens your immune system (e.g HIV/AIDS), or having a condition or taking medication that temporarily weakens your immune system (e.g. flu, mononucleosis, or measles, as well as chemotherapy drugs or organ transplant anti-rejection drugs)
4. Overactive immune system— this is when your immune system overreacts to substances and causes an allergic reaction. Examples include:
asthma
eczema
hayfever
How does immunisation work?
Immunisation (also known as vaccination) works by triggering the immune system’s ‘memory’. Small doses of antigen, such as dead or weakened live viruses, or mRNA (messenger ribonucleic acid) are injected into the body. The body then makes antibodies in response to these. If an immunised person is exposed to the actual virus at some point later on (e.g. the flu), then there is a reduced risk of getting sick (or seriously ill) because the body is more likely to recognise it and know how to attack it.
It’s worth noting that not all vaccinations provide complete protection from becoming sick. Instead, they may reduce the seriousness or length of the illness.
When to see a doctor
If you seem to get sick a lot or experience symptoms that never disappear, it’s worth visiting your doctor for a check-up, as they may be signs of a problem with your immune system, or may be linked to another health condition. Visit your doctor if you notice:
you’re always tired
you have sore, aching muscles or fever that you can’t attribute anything to
hair loss
inflammation or rashes anywhere on your body
fingers or toes that tingle or are numb
repeat infections or illnesses
How to boost your immune system
There are many things you can do to help keep your immune system healthy. These include:
not smoking
eating a healthy diet rich in fruit and vegetables
taking a multi-vitamin supplement if nutritional intake is not sufficient
limiting alcohol consumption
maintaining a healthy weight
getting plenty of sleep
regular exercise or movement
reducing stress
practising good hand hygiene
staying up-to-date with vaccines, especially your yearly flu shot or COVID-19 vaccine
Your local MediADVICE Pharmacist is available to help you manage your health. We can recommend a range of products, including vitamin supplements to help boost your immune health. We can also administer several vaccines including the annual Flu Vaccination, measles-mumps-rubella, meningococcal, whooping cough and COVID-19. Speak to your MediADVICE Pharmacist about your symptoms so we can recommend products and medications that may be suitable for you.
Book a vaccination at MediADVICE today