Nutrients to Support the Immune System

May 28th, 2020 | Posted in Info

If you’ve read the blog post The Importance of Nutrition for the Immune System you’ll be aware that nutrients from food and supplements play an important role in the development and preservation of the immune system. Nutrient deficiencies decrease immune defences, and increase susceptibility to infection (1).

As with any health matter, it is important to adopt a holistic approach rather than just dealing with the immediate threat or symptoms. Underlying health conditions have been shown to increase the severity of the coronavirus.  Now is a good time to support your overall health. Inflammation, gut health, cardiovascular health and insulin resistance may all need to be taken into consideration when devising a diet or supplement plan for any individual.

Here are some nutrients that have been shown to support the immune system and improve health.

Vitamin A – an important antioxidant. Also involved in the regulation of the immune system (2).

Vitamin C – unlike most mammals humans do not make our own vitamin C so have to get it from food or supplements. Vitamin C is a potent antioxidant and a cofactor for various enzymes. Vitamin C deficiency results in impaired immunity and higher susceptibility to infections. Having an infection increases the body’s requirements for vitamin C. Supplementation with vitamin C has been shown to help prevent and treat respiratory and systemic infections (3).

Vitamin D – results from the Irish Longitudinal Study on Ageing (TILDA) show that Vitamin D plays a critical role in preventing respiratory infections, reducing antibiotic use, and boosting the immune system’s response to infections (4). Vitamin D is produced by the action of sunlight on bare skin.  Getting outside is important where possible. Supplementing with Vitamin D3 and K2 (which aids the use of vitamin D in the body) may be helpful during the winter months and for those who aren’t able to get outside.

A new study has found an association between low average levels of vitamin D and high numbers of COVID-19 cases and mortality rates across 20 European countries (5).

Vitamin E – supplementing has been shown to enhance the function of the immune system and reduce the risk of respiratory infections and asthma (6). It also supports other antioxidants such as selenium.

Zinc – plays a part in many enzyme systems in the body. Zinc also has anti-inflammatory and anti-oxidant properties. There are clear benefits to the immune system from zinc supplementation (7).

Selenium – supplementation with selenium or multivitamins containing selenium have been shown to confer health benefits to those suffering from some bacterial or viral infections. Furthermore, selenium deficiency may lead to infections mutating into highly pathogenic strains (8).

Probiotics – have numerous beneficial properties including stimulation of the immune system (9).

N-acetylcysteine (NAC) – shown to reduce inflammatory compounds in lung tissue (10).

L-lysine – has anti-viral and immune supportive properties (11, 12).

Always consult your doctor before making dietary changes or taking any supplements, especially if you are pregnant or taking other medications.

For more information about who may be particularly at risk of COVID-19 see blog post Why COVID-19 Affects Different People in Different Ways.


1. Cell Mol Immunol. 13, 3–10 (2016).  The cytokine storm of severe influenza and development of immunomodulatory therapy Liu Q et al.

2. J Comp Physiol A Neuroethol Sens Neural Behav Physiol. 2020 Feb 7. Vitamin A: its many roles-from vision and synaptic plasticity to infant mortality. Dowling JE.

3. 2017 Nov 3;9(11). pii: E1211. Vitamin C and Immune Function. Carr AC, Maggini S.

4. Neuroscience news. April 7 2020. Could vitamin D help in fight against COVID-19?

5. Aging Clinical and Experimental Research,2020, The role of vitamin D in the prevention of coronavirus disease 2019 infection and mortality. Ilie PC et al. 

6. IUBMB Life 2019 Apr;71(4):487-494. Regulatory role of vitamin E in the immune system and inflammation. Lewis et al.

7. 2017 Nov 25;9(12). pii: E1286. Zinc as a Gatekeeper of Immune Function. Wessels et al.

8. Adv Nutr. 2015 Jan 15;6(1):73-82. Dietary selenium in adjuvant therapy of viral and bacterial infections. Steinbrenner H et al.

9. Crit Rev Food Sci Nutr. 2014;54(7):938-56. Immune system stimulation by probiotic microorganisms. Ashraf R. Shah NP.

10. Ter Arkh. 2018 Apr 19;90(3):89-95. Effect of N-acetylcysteine on mucosal immunity of respiratory tract. Kalyuzhin OV.

11. Cytotechnology (2001) Lysine: Is it worth more? Datta D, Bhinge A et al.

12. Biochemistry & Physiology: s5, pp. 1–5. 2015. The Effect of Zinc and Lysine Supplementation on Infection Rate and CD4 Count In Elderly. Sugeng MW.