IMMUNE BOOSTING: Fact or fiction

By Pia Skok

“Boost your immune system today, Shield your body from infections, Strengthen your immune system to fight disease, …” These are only a few of the headlines circling the internet with companies claiming their products can boost our immune system and protect us from various diseases. The idea of strengthening our immune system gained great attention last year as people were trying to protect themselves from the unknown SARS-CoV-2. In fact, an analysis of Google searches revealed that searches for phrases like ‘immune boost’ and ‘immune boosting’ spiked in early February, 2020 – right when the COVID-19 pandemic was starting to kick off (Rachul et al., 2020). Is this just a marketing technique used by celebrities and supplement companies, or can the immune system really be boosted?

The immune system is the body’s defence against bacteria, viruses, and parasites. It is made of many different types of white blood cells, tissues, organs, and proteins that work together . This network distinguishes our cells from foreign ones, clearing up dead cells and removes the invaders before they can cause damage. When the immune system encounters a pathogen, it triggers an immune response. B lymphocytes, a special type of leukocyte, recognize an antigen on the pathogen’s surface and begin secreting antibodies specific to that antigen. The antibodies lock onto the antigen – marking the pathogen for death, which is executed by a phagocyte, another type of leukocyte. Once antibodies are produced against a specific antigen, a copy remains stored in the body so that when exposed to the same pathogen again our body can respond much quicker to destroy it. This is called immunity. However, sometimes the immune system fails in targeting and killing a specific pathogen, so we get sick (Newman, 2018). To prevent this, we would have to boost or strengthen our immune system – by increasing the number of immune cells in the body (Harvard Medical School, 2021)

It has been shown that low white blood cell count increases your risk of getting an infection (NHS, 2020). This therefore suggests that by increasing the number of white blood cells or boosting our immune system, we decrease our chances of getting sick. However, increasing the number of white blood cells is not that simple, because the immune system consists of many different cells present in our body in specific amounts. We do not know the number of which cells would have to be increased (and to what value) to strengthen our immune system (Harvard Medical School, 2021)

The two most common products advertised as “immunity boosters” are supplements and probiotics. Vitamins A, D, and C, which are present in many of the “immunity boosting” supplements, are indeed essential for a well-functioning immune system. They play an important role in lymphocyte activation and proliferation, T-helper-cell differentiation, the production of specific antibody isotypes and regulation of the immune response (Mora et al., 2008). However, there is no evidence suggesting that large doses of these vitamins prevents any illness. Most people get enough of these vitamins through their diet (vitamin D is also produced in the skin from 7-dehydrocholesterol by UV irradiation (Bikle,  2017)) and therefore have no need to take supplements. In fact, taking in too much vitamin C can cause nausea, headaches, and diarrhoea (McCallum, 2020). Therefore, vitamin supplements are not beneficial to the immune system unless the person taking them is deficient (Harvard Health Publishing, 2020).

Similar to vitamins, probiotics (living bacteria and yeast) are essential for the health and well-being of the host. However, better comprehension of the mechanisms that connect the microbiome to the immune system, as well as extensive human studies are required to validate which probiotic strains are required to strengthen our immune system and prevent diseases (Ashaolu, 2020). Therefore, the idea of boosting one’s immunity as promoted by influencers and supplement companies is misleading and scientifically inaccurate. So far, there is no evidence that any product or practice will contribute to a stronger immune system (Wagner, 2020).

Although there is no supplement or treatment that can currently boost your immune system, adopting healthy habits can play a vital role in supporting your immune system and keeping it running well. Key to a strong immune system is a healthy, well-balanced diet with sufficient amounts of all macro- and micronutrients so that there is no need for additional supplements. Additionally, exercising for 30 minutes every day and staying active stimulates the immune system as it boosts the overall circulation. It also makes it easier for immune cells to travel throughout the body to remove pathogens or dead cells. Lastly, drinking enough water ensures that the movement of the lymph, a water-based fluid that makes up the circulatory system, is not slowed down and can carry immune cells throughout the body (McCallum,  2020).

There is no current evidence that any product or practice will contribute to the increased number of immune cells and an enhanced “immune boosting” protection. However, this lack of evidence has not stopped wellness gurus, celebrities, and supplement companies from propagating notions of boosting immunity. Although immune boosting is currently unproved, this might change in the future as more research is conducted on the connectivity of the immune system and the immune cell composition for optimal function. Until then, living a healthy and well-balanced life-style is the best way to support your immune system. 


Ashaolu, T. J. 2020. Immune boosting functional foods and their mechanisms: A critical evaluation of probiotics and prebiotics. Biomedicine & Pharmacotherapy. 2020 Oct; Vol 130. [online]. Available at: [Accessed 12th Jun 2021].

Bikle, D. 2017. Vitamin D: Production, Metabolism, and Mechanisms of Action. [online]. Available at: [Accessed 12th Jun 2021]. 

Harvard Health Publishing. 2021. How to boost your immune system. [online]. Available at: [Accessed 12th Jun 2021]. 

Harvard Health Publishing. 2020. Can supplements help boost your immune system? [online]. Available at: [Accessed 12th Jun 2021].

McCallum, K. 2020. Does Getting More Vitamin C Really Keep You From Getting Sick? [online]. Available at: [Accessed 12th Jun 2021].

McCallum, K. 2020. Does Getting More Vitamin C Really Keep You From Getting Sick? [online]. Available at: [Accessed 12th Jun 2021].

Mora, J. R. et al. 2008. Vitamin effects on the immune system: vitamins A and D take centre stage. Nat Rev Immunol. 2008 Sep; 8(9): 685–698.

Newman, T. 2018. How the immune system works. [online]. Available at: [Accessed 8th Jun 2021]. 

NHS. 2020. Low white blood cell count. [online]. Available at: [Accessed 12th Jun 2021].

Rachul, C. et al. 2020. COVID-19 and ‘immune boosting’ on the internet: a content analysis of Google search results. [online]. Available at: [Accessed 8th Jun 2021]. 

Wagner, D. N. 2020. “Immune Boosting” in the time of COVID: selling immunity on Instagram. Allergy Asthma Clin Immunol 16, 76 (2020). 

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