The immune system’s functions & how you can strengthen it

The immune system’s functions & how you can strengthen it

07 Sep 2021

The immune system consists of organs, cells, and chemicals that battle infection. It is the body’s first line of defence against harmful entities that enter our body (1). Our immune system consists of the following:

  • White blood cells
  • Antibodies
  • The lymphatic system
  • Spleen
  • Complement system
  • The thymus
  • Bone marrow

Each component of the immune system plays a specific part in actively fighting against infections and keeping us healthy.

How the immune system works

Active Immunity

Depending on the cause and site of infection, part of the immune system first recognises invader cells that have managed to enter the body. It then communicates this information to all other parts of the system (3).

The immune system’s frontline is the skin. Our skin resists the quick absorption of water and other substances to protect us from infection. It secretes oil that potentially kills off bacteria that sticks to us as we go on about our day (4).

Next in line are the white blood cells. They originate in the bone marrow and can be found in the lymphatic system. They often move around the blood to find any possible infection-causing microbes.

When identifying any microbe or foreign cell, the immune system launches an immune attack. Our immune system “remembers” infections it has dealt with before (5), thus protecting us from similar infections should they reoccur. In fact, this explains much of how vaccines work.

A vaccine safely injects the body with weakened strains of microbes or harmful proteins. Then, the body recognises the foreign bodies, so that it responds immediately with an attack. The immune system remembers this and can protect us from getting sick in the future.

Passive Immunity

Passive immunity is provided when a person is given antibodies to a disease rather than producing them through his or her own immune system.

One example is maternal passive immunity. A newborn baby acquires passive immunity from its mother through the placenta to protect the child from illness. An infant continues to receive passive immunity from disease through antibodies found in breast milk.

Artificial passive immunity comes from injected antibodies created within a different person or an animal. People may get passive immunity through antibody-containing blood products such as immune globulin.

How the immune system adapts to seasonal changes

Zinc benefits

Winter is a demanding season for the body (6). The body tends to adapt in physiological and behavioral ways when it comes to coping with the colder seasons.

Due to this, it is possible that the immune system can be compromised when subjected under severely stressful climate conditions (6). Which is why the flu is more common during winter. However, the immune system does its best in battling against infections by working overtime when weather conditions are harsh (6).

Top nutrients for immune health

A healthy diet can go a long way in boosting our immune system, especially when it includes fruits, vegetables, and whole grains (7). Each of these items can contribute the right nutrients that your immune system needs to function at its best. Here are examples of those nutrients:

Vitamin A

Vitamin A boosts the production of antibodies that battle foreign cells in the body (8). The best source for vitamin A is through food.

There is a certain type of vitamin A in organic foods that can fight inflammation in the body called carotenoids that are mostly found in green vegetables and sweet potatoes (9). Anti-inflammatory retinoids can also be found in milk, shrimp, and eggs.

Vitamin C

Vitamin C is essential in fighting colds and absorbing other nutrients, especially iron. It also plays a role in collagen synthesis, which keeps the skin healthy and glowing (10).

Vitamin C is also an antioxidant, helping other antioxidants like vitamin E regenerate more quickly. This process decreases the likelihood of infections in the body (11).

Good sources of vitamin C are strawberries, citrus fruits, tomatoes, and broccoli.

Vitamin D

Vitamin D functions more as a hormone than a vitamin. It plays a very unique role in strengthening immune responses—signaling the body to form compounds that boost the immune system (12).

Gain Vitamin D by spending time in the morning sun. Even five minutes of exposure can have plenty of benefits (12).

The foods rich in vitamin D are limited, but still accessible. Mackerel, sardines, egg yolks, and mushrooms can all provide you with sufficient vitamin D.


Long term zinc deficiency can increase production of pro-inflammatory cytokines (chemical messengers in the immune system) which can result in chronic inflammation and lead to the development of some autoimmune diseases.

With multiple components that communicate with each other, the immune system is reliant on nutrients and minerals to keep it working effectively and efficiently.

Among these is zinc. Not only does zinc benefit in boosting immunity, it also assists the brain’s multiple functions, synthesising DNA and proteins in the body (13).

Zinc is able to assist neutrophils and macrophages, which are immune cells. It has antiviral properties which help the body in fighting bacteria (13).

Good sources of zinc are beef, yogurt, chicken, and cashews.

Protect your immune system so it protects you

The immune system is a high-maintenance part of your body that requires constant sustenance and strengthening.

Especially in “the new normal”, minerals like vitamins A, C, D and zinc play an important role in shoring up immunity to help you fight infections and remain healthy.

Now that you know how to introduce the best benefits for your immune system, why not look to improve other areas of your health too? Get your very own custom supplements with Vitable and pair them up with a healthy lifestyle for maximum benefits. We'll give you the option to put together a mix of these supplements to create a personalised vitamin subscription pack. We'll even take care of the vitamin delivery right to your doorstep in Australia.

Learn more about other areas that zinc can help you with, plus other supplements that can benefit in different ways:

Zinc | Iron | Astaxanthin | Ashwagandha | Probiotics SB | B complex | Vitamin C | Vitamin D | Daily probiotics | Vitamin B12 | Fish oil | Biotin

*Always read the label. Follow the directions for use. If symptoms persist, talk to your health professional. Vitamin and/or mineral supplements should not replace a balanced diet.


1. BetterHealth. Immune system explained. BetterHealth. Published 2015 on . Accessed on 13 August 2021.

2. International immunopharmacology. SARS-Cov-2 infection: Response of human immune system and possible implications for the rapid test and treatment. di Mauro, G., Scavone, C., Rafaniello, C., Rossi, F., & Capuano, A. (2020). , 84, 106519.

3. National Center for Biotechnology. How does the immune system work? Institute for Quality and Efficiency in Health Care. Published  23 April 2020  on /. Accessed on 13 August 2021.

4. International journal of molecular sciences, 20(8), 1811. The Dynamics of the Skin's Immune System. Nguyen, A. V., & Soulika, A. M. (2019).

5. Janeway CA Jr, Travers P, Walport M, et al. Immunobiology: The Immune System in Health and Disease. 5th edition. New York: Garland Science; 2001. Immunological memory.

6. National Library of Medicine. Seasonal changes in immune function. R.J. Nelson, G. E. Demas. Published 7 December 1996 on . Accessed on 13 August 2021.

7. Childs, Caroline E et al. “Diet and Immune Function.” Nutrients vol. 11,8 1933. 16 Aug. 2019, doi:10.3390/nu11081933

8. Journal of Clinical Medicine. Role of Vitamin A in the Immune System. Zhiyi Huang, Yu Liu, Guangying Qi, David brand, Song Guo Zheng. Published 6 September 2018 on Accessed on 13 August 2021

9. HealthDirect.   Vitamin A.   HealthDirect. Published March 2019 on Accessed on 13 August 2021.

10. HealthDirect   Vitamin C   HealthDirect  Published  March2020  on . Accessed on  13 August 2021

11. National Center for Biotechnology   Vitamin C and Immune Function   Anitra Carr, Silvia Maggini  Published  3November2017  on . Accessed on  13 August 2021

12. BetterHealth.  Vitamin D. BetterHealth. Published  2017  on Accessed on 13 August 2021.

13. HealthDirect.  Vitamins and Minerals. HealthDirect. Published May 2020 on Accessed on 13 August 2021.