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What is the immune system?

It is common knowledge that a strong immune system offers protection against viruses and diseases, while a weak one makes you more susceptible to catching a cold or worse. But what exactly is it and how does it work? Let’s take an in-depth look at immunity!

The definition of immunity

Simply put, immunity is your body’s ability to resist toxins, infections and other harmful substances or microorganisms with the use of sensitized white blood cells or specific antibodies. Think of it as a protection system – this is how your body defends itself. If it wasn’t for the immune system, various bacteria, viruses and even fungi could attack or infect your body at will. Thanks to immunity, that’s not the case.

Different types of immunity

There are 4 types of immunity – 3 natural and an additional one:

  • Innate immunity – the one we are born with. This is our innate immune system. It varies in strength; some people are born with a strong immune system, while some are born with a weak immune system.
  • Adaptive immunity – also called “acquired immunity”. The adaptive immune system protects us based on its past “experience”. This is why, after being infected with something and getting better, we are no longer (at least for some time) susceptible to the same infection.
  • Passive immunity – temporary immunity, also called “borrowed immunity”. This is an immunity which we gain from another person, i.e. a child borrowing temporary immunity from the mother through her breast milk.
  • Immunizations – we can be made immune to something – typically through the administration of a vaccine.

The purpose and functions of the immune system

The main function of the immune system is to protect you from harmful microorganisms that may cause infections. However, it doesn’t stop at prevention – if you do get sick, it is your immune system that is your body’s first line of defence. It will fight the infection and act to minimize the damage done to your body. A healthy immune system will be able to fight off most infections. A weakened immune system means your illness can last longer, and symptoms may be more severe.

Woman playing with her daughter and throwing her into the air

How to bolster your immune system

A healthy lifestyle is the best immune booster. It’s always a good idea to ensure you look after your immune system on a daily basis. Below you will find a few tips on how to keep your immune system healthy and strong through everyday activities1. Remember that if you think your immunity might be weakened, you should always consult your doctor.

  • Eat a balanced diet, including lots of fresh fruit and vegetables. A healthy diet will provide essential vitamins and minerals your immune system needs to function properly.
  • If you are not sure you are getting enough vitamins and minerals in your diet, consider adding a supplement like Cal-C-Vita® that can help strengthen your immune system2.
  • Get regular exercise3. This will help reduce stress, which negatively affects immunity, and improve blood circulation, allowing white blood cells to reach any cells affected by disease.
  • Take steps to reduce stress. If you find you are under persistent stress, you can try meditation techniques or yoga.
  • Get quality sleep. Rest allows your body to regenerate and helps your immune system to work adequately.
  • Maintain a healthy weight. People who are overweight have weakened immune function, which can make them more at risk of catching illnesses.4
  • Get proactive to avoid infection. Wash your hands thoroughly  and regularly, avoid sharing personal items if sharing space with an infected person and make sure any meat you eat is properly cooked.
  • Don’t smoke. Smoking tobacco is harmful to your immune system and can make it less effective at fighting diseases.
  • Limit alcohol consumption. Alcohol can damage your immune response.


  1. How to prevent infections. Harvard Medical School, 2016. (Accessed 10/02/2020, at
  2. Gombart AF, Pierre A, Maggini S. A Review of Micronutrients and the Immune System-Working in Harmony to Reduce the Risk of Infection. Nutrients 2020;12.
  3. Nieman DC, Wentz LM, The Compelling Link Between Physical Activity and the Body’s Defense System, Journal of Sport and Health Science, vol 8, issue 3, May 2019, p 201-217
  4. Andersen CJ, Murphy KE, Fernandez ML, Impact of Obesity and Metabolic Syndrome on Immunity, ADVANCES IN NUTRITION, Volume 7, Issue 1, January 2016, Pages 66–75,

How Cal-C-Vita®
helps support your
immune system




Your body is equipped with powerful natural defences and your immune system has many ways of dealing with threats from bacteria and viruses. The Immune system is made up of three main defences mechanisms; Physical barriers (skin and mucosa), cellular barriers (white blood cells) and antibodies. Nutrients such as vitamins and minerals are essential to the health and function of this complex network.

In our fast-paced world of fast food and pre-cooked meals, it may be challenging to consume adequate amounts of fruits and vegetables delivering all the vitamins and minerals we need to fully support our body functions. An inadequate intake of vitamins and minerals can negatively affect the immune system and overall health. That’s where Cal-C-Vita® comes in. Our range of Vitamin C products are designed to help support your immune system.

Learn more


Cal-C-Vita® for a healthier immune system

You need to look after your immune system. Even though it may not feel like it, your immune system works 24 hours a day. Just as a plant needs water and sunlight, your immune system needs regular nourishment to support the body’s defence systems.

Together with a healthy lifestyle including physical exercise and good nutrition, supplements like Cal-C-Vita® provide the foundation for a strong immune system all year round.






80 years of vitamin C expertise

In 1934, we pioneered the world’s first Vitamin C supplement, and we’ve been helping people keep their natural defenses in top shape for over 80 years. Today our range of innovative supplements helps to support your immunity every day.


Build your immunity

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