Zinc is an essential trace element that has a crucial role for growth, development, and the maintenance of antiviral immunity. Its influence reaches all organs and cell types, representing an integral component of approximately 10% of the human proteome, and encompassing hundreds of key enzymes and transcription factors.
Zinc deficiency is strikingly common, affecting up to a quarter of the population in developing countries. But also affecting distinct populations in the developed world as a result of lifestyle, age, and disease-mediated factors. Consequently, zinc status is a critical factor that can influence antiviral immunity. Particularly as zinc-deficient populations are often most at risk of acquiring viral infections such as HIV or hepatitis C virus.
This review summarizes current basic science and clinical evidence examining zinc as a direct antiviral, as well as a stimulant of antiviral immunity. An abundance of evidence has accumulated over the past 50 y to demonstrate the antiviral activity of zinc against a variety of viruses, and via numerous mechanisms. The therapeutic use of zinc for viral infections such as herpes simplex virus and the common cold has stemmed from these findings. However, there remains much to be learned regarding the antiviral mechanisms and clinical benefit of zinc supplementation as a preventative and therapeutic treatment for viral infections.
Although zinc is a component of ∼10% of the human proteome, zinc in different forms (free compared with protein-bound) can stimulate a variety of signaling events, including the antiviral response. In vitro studies suggest that free zinc may possess potent antiviral effects. These are supported by trials of creams, lozenges, and supplements with high free zinc content. Moreover, zinc-binding proteins such as the metallothioneins may possess antiviral roles, although their specific function remains uncertain.
Nonetheless, zinc treatment applied at a therapeutic dose and in the right form has the potential to drastically improve the clearance of both chronic and acute viral infections, as well as their accompanying pathologies and symptoms. Consequently, the role of zinc as an antiviral can be separated into 2 categories. 1) Zinc supplementation implemented to improve the antiviral response and systemic immunity in patients with zinc deficiency. And 2) Zinc treatment performed to specifically inhibit viral replication or infection-related symptoms.
The Role of Zinc in Antiviral Immunity, Scott A Read,1,2 Stephanie Obeid,3 Chantelle Ahlenstiel,3 and Golo Ahlenstiel1,2
1Blacktown Medical School, Western Sydney University, Blacktown, New South Wales, Australia; 2Storr Liver Centre. The Westmead Institute for Medical Research, The University of Sydney and Westmead Hospital,Westmead, New SouthWales, Australia. And The Kirby Institute, University of New SouthWales, Sydney, New SouthWales, Australia
Adv Nutr 2019;10:696–710; doi: https://doi.org/10.1093/advances/nmz013
