Zinc deficiency and the immune system
Ask any of the local LifeLab phlebotomists that work in proximity to our office and they’re likely to tell you that I order lots of serum zinc tests. Ask our staff and you’ll also find that there is hardly an IV bag administered that doesn’t contain it.
So why am I so bullish on zinc?
Lots of reasons, including...
It’s vital for growth and development. It’s critical to wound healing. It helps maintain healthy bones, skin, hair, and nails. It’s absolutely vital to optimizing neurotransmitter function and neuropsychology. It impacts digestive and cardiovascular health. It plays a role in visual function, hearing, and taste.
Zinc is also absolutely critical in helping optimize immune function.
Acting as second messengers, zinc helps modulate and control virtually all aspects of our immune response. Second messengers are intracellular signalling molecules and without them, the immune system effectively shuts down. Beyond this vital role in cell-mediated immunity, zinc also acts as an antioxidant and as an anti-inflammatory. (1)
As COVID cases continue to escalate globally, it’s easy to see why the interest in zinc has also piqued.
More on this a little later.
The correlation between zinc and the immune function first came to light in the 1960s when doctors found underdeveloped people in small villages in rural Iran who were dying of intercurrent infections before the age of 25. One of the principal culprits was a zinc deficiency due to the high phytates (zinc-binding) present in their wheat dominant diet. (2)
Zinc deficiency was a controversial medical idea in the 1960s and it wasn’t until 1974 that zinc was deemed an essential nutrient for human health by the Academy of Sciences. (3)
My lab tests would suggest that the problem with zinc deficiency hasn’t gone away. The World Health Organisation (WHO) would likely concur. According to their published report, one-third of the entire global population is mildly to moderately deficient in zinc. (4)
Back to COVID.
These last several weeks heralded the news of two potential vaccines that may be used as prophylaxis against the virus. At the present moment however, therapeutic strategies are only supportive and the only deemed effective preventive measures include those associated with basic infection control including wearing masks and social distancing.
This hasn’t stopped clinicians and scientists from dreaming aloud however as one wrote in the Journal of Medical Hypotheses, “Zn supplementation may be of potential benefit for prophylaxis and treatment of COVID-19, since it possesses a variety of direct and indirect antiviral properties, which are realized through different mechanisms.” (5)
In fact numerous review articles have surfaced over the last six months hypothesizing zinc’s potential protective role against COVID-19.
The leap seems pretty simple. Beyond its antiviral and immunomodulatory properties, zinc helps suppress inflammatory cytokines, has been shown to inhibit SARS-coronavirus RNA polymerase activity, and is even a potential risk factor for pneumonia in the elderly. (6,7)
Exciting stuff! Here’s the issue...
There is no direct clinical data supporting the use of zinc with COVID-19 specifically.
In conducting a literature review hoping to corroborate the above hypotheses linking “Zinc and COVID-19”, I found a whopping zero published clinical case studies and a further zero meta analyses examining the two.
So clearly our ability to overly project benefit should be radically tempered.
But here’s what the research does show according to a published article in this month’s International Journal of Infectious Diseases. (8)
Patients with coronavirus disease 2019 (COVID-19) had significantly low zinc levels in comparison to healthy controls.
Zinc deficient patients developed more complications (70.4% vs 30.0%, p = 0.009).
Zinc deficient COVID-19 patients had a prolonged hospital stay (7.9 vs 5.7 days, p = 0.048).
So where does that leave us, practicing naturopathic medicine in the trenches with our patients, who lie in wait for the development and distribution of a safe vaccine?
The answer is simple.
Check Zinc status. Improve zinc status.
What about vitamin D or vitamin C status? What about sleep or stress? What about obesity or diabetes? What about…
Stay tuned, more to come.
(1) Haase, Hajo, and Lothar Rink. “Functional significance of zinc-related signaling pathways in immune cells.” Annual review of nutrition vol. 29 (2009): 133-52. doi:10.1146/annurev-nutr-080508-141119
(2) Prasad, Ananda S. “Zinc in human health: effect of zinc on immune cells.” Molecular medicine (Cambridge, Mass.) vol. 14,5-6 (2008): 353-7. doi:10.2119/2008-00033.
(3) Prasad, Ananda S. “Discovery of human zinc deficiency: its impact on human health and disease.” Advances in nutrition (Bethesda, Md.) vol. 4,2 176-90. 1 Mar. 2013, doi:10.3945/an.112.003210
(5) Kumar, Amit et al. “Potential role of zinc supplementation in prophylaxis and treatment of COVID-19.” Medical hypotheses, vol. 144 109848. 25 May. 2020, doi:10.1016/j.mehy.2020.109848
(6) Skalny, Anatoly V et al. “Zinc and respiratory tract infections: Perspectives for COVID‑19 (Review).” International journal of molecular medicine vol. 46,1 (2020): 17-26. doi:10.3892/ijmm.2020.4575
(7) te Velthuis, Aartjan J W et al. “Zn(2+) inhibits coronavirus and arterivirus RNA polymerase activity in vitro and zinc ionophores block the replication of these viruses in cell culture.” PLoS pathogens vol. 6,11 e1001176. 4 Nov. 2010, doi:10.1371/journal.ppat.1001176
(8) Jothimani, Dinesh et al. “COVID-19: Poor outcomes in patients with zinc deficiency.” International journal of infectious diseases : IJID : official publication of the International Society for Infectious Diseases vol. 100 (2020): 343-349. doi:10.1016/j.ijid.2020.09.014