Zinc is a crucial mineral necessary for all aspects of immunity. Zinc is present in all tissues and body fluids, and plays such an important role in general physiology, that it is obvious a deficiency of this mineral will seriously impair homeostasis and health.

In fact zinc is part of more enzyme systems than any other mineral. Some of the functions of zinc-dependent enzymes include the disposal of carbon dioxide in red blood cells, alcohol breakdown, bone formation, protein digestion, haeme synthesis, folate metabolism, DNA and RNA transcription, cell growth, skin integrity (membrane stability), insulin signalling and basal metabolism.¹

The list includes immune defences necessary to protect against any pathogen including those common cold viruses we face on a daily basis. Unfortunately, SARS-CoV-2 is becoming one of the several coronaviruses that circulate each year along with adenoviruses, rhinoviruses, enteroviruses and flu viruses.

Even with many countries mandating vaccination, and schedules already reaching three or four shots with more to come, it is clear that other measures are going to be critical for maintaining immune health alongside effective vaccines (my double Astra-Zeneca is now obsolete in Australia). In fact, New Zealand, a country which once had a rigid COVID-zero policy like Australia, abandoned its vaccine mandates for most non-healthcare workers after it became obvious that the virus was widespread even with widespread vaccination (500,000 cases in a population of 5.1 million, 95% double vaccinated).

Most people should now be aware that vaccines assist the body to fight an infection, they don’t prevent infection (your body must fight something). Unfortunately, this is a particularly virulent virus which actively suppresses immunity, delaying antibody synthesis up to 2 weeks.² Yes, vaccination does give a valuable head start with antibodies active from day 1 in this period of natural antibody suppression, and the improved prognosis of infected patients bears this out; however, a dilemma is the relatively short-term protection provided by vaccines due to antibody fade, compared to long-term persistence with other effective vaccination programs such as those for measles and polio.

In Australia, people are still being given the ultimatum of getting ‘the jab’ or losing their job, despite ATAGI recommending a four month deferral after a PCR-confirmed natural infection. My doctor told me that the booster is advised even one week after an infection, as if a natural infection offered no equivalent immune response (whatever happened to herd immunity through infection?). In any case, he told me that even as a medical expert he can’t give an exception to satisfy my employer, I have to apply for it through bureaucratic channels, a process which may take several months.

Nevertheless, it is clear on the street that not enough people care anymore about the only measures that offer common-sense protection for the herd during this ongoing crisis as was learned in the SARS epidemic (2002-2004) when no vaccination was available: masks, social distancing, hand washing and staying home when sick. On top of these basic measures, the best ways to maintain immune health is to eat a healthy diet, avoid factory foods, get plenty of exercise, rest adequately after hard work and illness, and avoid stress. Long-term stress saps immunity like nothing else.

Long before the modern era in medicine, Hippocrates wrote about the importance of what was known as diet and regimen, or nutrition and healthy lifestyle. Two thousand years later the vitamin pioneer Dr Robert McCarrison investigated and discovered the role that a deficiency of essential nutrients plays in disease aetiology.³ Anaemia, scurvy, pellagra, rickets, goitre and many other conditions were soon found to have a simple cure in the provision of a healthy diet, a lesson that is still often overlooked today due to our obsession with complex medical procedures and expensive cutting-edge drugs.

Add to the widespread deficiency of nutrients in a diet consisting of high levels of ultra-processed foods a rising level of toxic endocrine-disrupting chemicals, and the problem of an adequate diet takes on startling dimensions.⁴ Our medical forebears could never have imagined that pesticides, herbicides, plasticisers, flame retardants and so on, in concentrations a slow as parts per trillion, could affect health, not only in our generation, but be passed on epigenetically to those of the future.⁵

As far as zinc is concerned, it should be obvious that a deficiency of this crucial mineral would seriously suppress innate and adaptive immune defences. A recent study in India tested COVID patients in a clinic against healthy volunteers and measured significant zinc deficiency in the patients at 27/47, compared to 4/45 for the healthy volunteers. The patients with zinc deficiency experienced a longer hospital stay with more corticosteroid administration, ICU stay and deaths, compared to patients with normal zinc levels. All patients were given hydroxychloroquine, antibiotics, multivitamins and zinc (150mg) after testing. The researchers could not be certain if the zinc deficiency preceded infection or resulted from it; nevertheless, both scenarios argue for an adequate provision of zinc in the diet as well as supplementation for increased protection and treatment during illness.⁶

A feature of COVID is a disordered inflammatory response that in some cases results in a cytokine storm. This appears to occur later in the infection at around 10 days after innate immune mechanisms have produced an initial inflammatory response. This later stage occurs when the adaptive response produces antibodies in the blood specific for the virus. The initial infection prompts a non-specific reaction which inhibits viral replication by producing type-I interferons (IFN), IFN-α and IFN-β. Meanwhile, T and C lymphocytes begin maturation in lymph nodes and when the resulting antibodies appear in the blood they initiate a second wave of inflammation. Zinc deficiency leads to the reduction of important immune cells (lymphopenia), reduces survival of remaining immune cells, hinders phagocytosis and viral cell killing, as well as inhibiting the activation of both T helper and CD8+ cells.⁷

It is obvious therefore that zinc supplementation can improve innate defences as well as adaptive defences. Of the first type, zinc improves ciliary function in the lungs and thereby clearance of the virus, as well as lowering the risk of secondary bacterial infection (pneumonia). It also improves epithelial barriers (skin integrity) against entry by viral particles. The general inflammatory response is also modulated as mentioned above, tending to inhibit the progression of a dysregulated cytokine storm. Interestingly, zinc also plays a role as an antioxidant nutrient, being able to help reduce collateral damage caused by local inflammation in lung tissue and in other organs arising from systemic inflammation. In addition, zinc may be considered a specific antiviral nutrient: ‘zinc can prevent fusion with the host membrane, decreases the viral polymerase function, impairs protein translation and processing, blocks viral particle release, and destabilizes the viral envelope.’⁸

Importantly, the above paper mentions that around 50% of COVID deaths involved bacterial or fungal infections, indicating the need for broad immune system support. This may include straightforward measures that can help build protection against COVID infection beyond the measures already mentioned for diet and regimen. These include the consumption of specific antioxidant and anti-inflammatory superfoods, other minerals, vitamins, and antiviral herbal medicines (echinacea, liquorice, andrographis, garlic).

In this respect, the literature provides evidence-based studies to support selenium, vitamin D, vitamin C and melatonin supplementation. Vitamin D, which is commonly found to be deficient in the elderly, modulates T-cell cytokines, corrects excessive antibody production, suppresses viral adhesion and cell entry, as well as disrupts viral membranes; vitamin C is an immune modulator, combats oxidative stress, is anti-viral and anti-inflammatory; selenium forms antioxidant glutathione, as well as inhibiting SARS-CoV-2; while melatonin is also immuno-regulatory and an antioxidant, while population studies show higher levels are associated with reduced chances of being infected with COVID.^9,10

A word of caution, studies concerning zinc often use high doses to correct deficiency which will cause nausea in the sort-term and copper or iron deficiency in the long-term. The diet can provide adequate zinc if it consists of unrefined wholefoods such as grains and seeds, organ meats, beef, organic eggs and shellfish. The RDA is 15mg.

Special:

If you would like to know more about medicinal herbs and wholefoods an A-Z eBook is available which is comprised of essays with references from traditional herbals as well as the current medical evidence-base. Many of these essays are also available free on this website in abridged form under the wholefoods and herbs tab.

Disclaimer:

This article is intended for the purpose of general education only, and is not a substitute for a diagnosis, treatment advice, or a prescription given in a consultation with a qualified physician.

References:

1.         Gropper, Smith, Groff. Advanced Nutrition And Human Metabolism. 5th ed. Wadsworth: Cengage Learning; 2009.

2.         Jeyanathan M, Afkhami S, Smaill F, Miller MS, Lichty BD, Xing Z. Immunological considerations for COVID-19 vaccine strategies. Nat Rev Immunol 2020;20:615–32.

3.         McCarrison R. Studies in deficiency disease. London: Frowde, Hodder & Stoughton; 1921.

4.         Machado PP, Steele EM, Levy RB, et al. Ultra-processed food consumption and obesity in the Australian adult population. Nutr Diabetes 2020;10:1–11.

5.         Leu A. The Myths Of Safe Pesticides. US: Acres; 2014.

6.         Jothimani D, Kailasam E, Danielraj S, et al. COVID-19: Poor outcomes in patients with zinc deficiency. Int J Infect Dis 2020;100:343–9.

7.         Pal A, Squitti R, Picozza M, et al. Zinc and COVID-19: Basis of Current Clinical Trials. Biol Trace Elem Res 2021;199:2882–92.

8.         Wessels I, Rolles B, Rink L. The Potential Impact of Zinc Supplementation on COVID-19 Pathogenesis. Front Immunol 2020;11:1712.

9.         Alexander P. It Could Be Allergy And It Can Be Cured. Dee Why: Ethicare; 1990.

10.       Corrao S, Mallaci Bocchio R, Lo Monaco M, et al. Does Evidence Exist to Blunt Inflammatory Response by Nutraceutical Supplementation during COVID-19 Pandemic? An Overview of Systematic Reviews of Vitamin D, Vitamin C, Melatonin, and Zinc. Nutrients 2021;13:1261.