12.01.21
Zinc, an essential mineral long-studied for its role in immune function, may help to prevent or shorten the symptoms associated with respiratory tract infections, according to a review published in the British Medical Journal.
“Except for influenza and SARS-CoV-2 vaccinations, prophylactic and therapeutic options are limited [for respiratory tract infections]. Clinical practice guidelines focus on hand hygiene, reducing inappropriate antibiotic use, and symptomatic relief with over-the-counter medications. Some guidelines recommend zinc. However, systematic reviews of zinc are limited by variations in administration route or formulation, are outdated, have been withdrawn, or are low quality. The mechanisms for how zinc might work include broad spectrum antiviral properties in vitro against most of the common respiratory viruses, including coronaviruses. Zinc is important for immunity, inflammation, haemostasis, ACE 2 activity, and also assists with tissue responses to hypoxia.”
In the review, researchers included 28 randomized, placebo-controlled human clinical studies which comprised the health outcomes of a total of 5,446 participants. Most of the studies involved the use of zinc lozenges, followed by nasal sprays, and gels containing either zinc acetate or gluconate salts, with dosages varying significantly depending on the delivery format used.
When analyzing the results of the studies included, none of which were specific to SARS-CoV-2, the authors of the study found a number of significantly beneficial relationships between zinc supplementation and RTI outcomes, even in populations that were not zinc deficient:
- Oral or intranasal zinc prevented 5 RTIs per 100 person-months.
- On average, zinc supplementation reduced RTI symptoms 2 days earlier than placebo
- Adults who didn’t supplement with zinc were 19% more likely to remain symptomatic seven days after contracting an RTI.
For these reasons, the authors concluded that zinc might prevent RTI symptoms, and shorten their duration, although healthy adults may experience some non-serious adverse events including nausea and mouth/nasal irritation.
“Zinc is readily available for consumers to self-prescribe. The marginal benefits, strain specificity, drug resistance, and potential risks of other over-the-counter and prescription medications makes zinc a viable ‘natural’ alternative for the self-management of non-specific RTIs. It also provides clinicians with a management option for patients who are desperate for faster recovery times and might be seeking an unnecessary antibiotic prescription,” the authors wrote.
However, they noted that uncertainty remains on which zinc formulation, dose, or administration route is most effective. While the most evidence has been gathered on sublingual lozenges and gels, they said, this doesn’t mean that other administration routes are less effective, and a minimum therapeutic dose has yet to be determined.
“Except for influenza and SARS-CoV-2 vaccinations, prophylactic and therapeutic options are limited [for respiratory tract infections]. Clinical practice guidelines focus on hand hygiene, reducing inappropriate antibiotic use, and symptomatic relief with over-the-counter medications. Some guidelines recommend zinc. However, systematic reviews of zinc are limited by variations in administration route or formulation, are outdated, have been withdrawn, or are low quality. The mechanisms for how zinc might work include broad spectrum antiviral properties in vitro against most of the common respiratory viruses, including coronaviruses. Zinc is important for immunity, inflammation, haemostasis, ACE 2 activity, and also assists with tissue responses to hypoxia.”
In the review, researchers included 28 randomized, placebo-controlled human clinical studies which comprised the health outcomes of a total of 5,446 participants. Most of the studies involved the use of zinc lozenges, followed by nasal sprays, and gels containing either zinc acetate or gluconate salts, with dosages varying significantly depending on the delivery format used.
When analyzing the results of the studies included, none of which were specific to SARS-CoV-2, the authors of the study found a number of significantly beneficial relationships between zinc supplementation and RTI outcomes, even in populations that were not zinc deficient:
- Oral or intranasal zinc prevented 5 RTIs per 100 person-months.
- On average, zinc supplementation reduced RTI symptoms 2 days earlier than placebo
- Adults who didn’t supplement with zinc were 19% more likely to remain symptomatic seven days after contracting an RTI.
For these reasons, the authors concluded that zinc might prevent RTI symptoms, and shorten their duration, although healthy adults may experience some non-serious adverse events including nausea and mouth/nasal irritation.
“Zinc is readily available for consumers to self-prescribe. The marginal benefits, strain specificity, drug resistance, and potential risks of other over-the-counter and prescription medications makes zinc a viable ‘natural’ alternative for the self-management of non-specific RTIs. It also provides clinicians with a management option for patients who are desperate for faster recovery times and might be seeking an unnecessary antibiotic prescription,” the authors wrote.
However, they noted that uncertainty remains on which zinc formulation, dose, or administration route is most effective. While the most evidence has been gathered on sublingual lozenges and gels, they said, this doesn’t mean that other administration routes are less effective, and a minimum therapeutic dose has yet to be determined.
