Can Zinc Help You Fight COVID-19?
Dr. Ian Tullberg bears no responsibility for the above comparison. But as far as helping patients get over colds, “there’s good evidence that oral zinc works well,” the medical director of UCHealth Medical Group Urgent Care said.
With respect to the specific coronavirus that is causing the pandemic now, “the problem is that this is still so early that we don’t have the knowledge if it works or not,” Tullberg said. “However, zinc is something that will not hurt you, and there may be some benefit.”
Those who swear by zinc as a cold remedy know to take it when they first start to feel a scratchy throat. They try to hit it early – right when the cold’s coming on. Research spanning decades has shown that using zinc lozenges through the course of the cold does make a difference.
The data around Zinc and coronaviruses
A study published in 1996 shuffled 100 Cleveland Clinic employees who self-reported catching colds into two groups. Fifty took lozenges containing 13.3 milligrams of zinc gluconate – the dosage of today’s Cold-Eeze and other over-the-counter lozenges – every two hours as long as they had cold symptoms. Fifty others took placebo lozenges. The study was double-blind, so neither patients nor researchers knew which patients had the placebo. The findings: the zinc group cleared symptoms more than three days earlier – 4.4 days versus 7.6 days of the placebo group, and, until that point, suffered fewer days with cough, headache, hoarseness, nasal congestion, and sore throat (fever, muscle aches, scratchy throat and sneezing remained similar during the cold’s duration). Zinc has side effects – “bad-taste reactions” (understandable) and, among 20 percent of those taking zinc, nausea.
That study wasn’t, it turned out, a fluke. A Cochrane review updated in 2013 summarized 18 randomized controlled trials involving 1,781 participants across all age groups found that zinc – particularly in lozenge or syrup form – “inhibits replication of the virus” that cause the common cold and shortens average duration of the common cold when taken within 24 hours of onset of symptoms at a dose of more than 75 milligrams a day.
A 2010 study led by University of Leiden Medical researchers in the Netherlands sought to understand how zinc inhibited that replication. The team reported that zinc inhibits a cousin of SARS-CoV-2: SARS-CoV, the original SARS of the 2003 outbreak. Click through for details, which get into the biochemical nitty-gritty, but the gist is that zinc throws a wrench in the virus’s RNA-synthesis machine.
Now, there are caveats with zinc. First, like everything else, there can be too much of a good thing – more than 150 milligrams a day for adult. That’s about 11 lozenges; the recommended zinc-lozenge maximum for adults being six and just four for children ages 12-17 (research has shown younger children to not benefit from taking zinc). Second, zinc nasal sprays shouldn’t be used, Tullberg says. In 2009, the U.S. Food and Drug Administration warned against such products because people who used them lost their sense of smell.
What does that background say about the effectiveness of zinc and the SARS-CoV-2 now known as coronavirus? It is, at best, effectiveness by association. But an email that recently went viral as a blog post indicates that Tullberg is in good company with his openness to zinc lozenges as a way to at least try and mitigate COVID-19 flu symptoms.
A virologist’s take on Zinc and COVID-19
The email was one that James A. Robb sent to friends and family. He is University of Colorado School of Medicine MD, a pathologist, and molecular virologist who, while at the University of California, San Diego in the 1970s, did pioneering work in understanding coronaviruses. He wrote:
For all updates and to read more articles about the new coronavirus, please visit uchealth.org/covid19
Stock up now with zinc lozenges. These lozenges have been proven to be effective in blocking coronavirus (and most other viruses) from multiplying in your throat and nasopharynx. Use as directed several times each day when you begin to feel ANY “cold-like” symptoms beginning. It is best to lie down and let the lozenge dissolve in the back of your throat and nasopharynx. Cold-Eeze lozenges is one brand available, but there are other brands available.
Snopes.com, a website dedicated to debunking (or confirming) internet myths, investigated after his words were twisted by others and reposted with exaggerated claims such as zinc being a “silver bullet” against coronavirus. In an email to Snopes, Robb confirmed that he’d written the above and added, “In my experience as a virologist and pathologist, zinc will inhibit the replication of many viruses, including coronaviruses. I expect COVID-19 will be inhibited similarly, but I have no direct experimental support for this claim. I must add, however, that using zinc lozenges as directed by the manufacturer is no guarantee against being infected by the virus, even if it inhibits the viral replication in the nasopharynx.”
In short, if COVID-19 is like other “common cold” causing corona viruses zinc lozenges may be something that helps the immune system stay in shape and be even more ready to take it on but we don’t know for sure. Zinc in daily doses under 40 mg has no side effects so what can it hurt.
How does Zinc work?
Zinc is needed for the proper growth and maintenance of the human body. It is found in several systems and biological reactions, and it is needed for immune function, wound healing, blood clotting, thyroid function, and much more. Meats, seafood, dairy products, nuts, legumes, and whole grains offer relatively high levels of zinc.
Zinc plays a key role in maintaining vision, and it is present in high concentrations in the eye. Zinc deficiency can alter vision, and severe deficiency can cause changes in the retina (the back of the eye where an image is focused).
Zinc might also have effects against viruses. It appears to lessen symptoms of the rhinovirus (common cold), but researchers can’t yet explain exactly how this works. In addition, there is some evidence that zinc has some antiviral activity against the herpes virus.
Low zinc levels can be associated with male infertility, sickle cell disease, HIV, major depression, and type 2 diabetes, and can be fought by taking a zinc supplement.
*Note that many zinc products also contain another metal called cadmium. This is because zinc and cadmium are chemically similar and often occur together in nature. Exposure to high levels of cadmium over a long time can lead to kidney failure. The concentration of cadmium in zinc-containing supplements can vary as much as 37-fold. Look for zinc-gluconate products. Zinc gluconate consistently contains the lowest cadmium levels.