Why Zinc Lozenges for Coronavirus?

Chickpeas in a bowl. Chickpeas, like legumes, are a rich source of zinc. Why zinc lozenges when chickpeas are a good source of zinc as part of a balanced diet?
Chickpeas are a rich source of zinc. Ionized zinc may play a role in reducing duration of common colds.

With all the coronavirus home treatments, why zinc lozenges? Zinc has long been studied for anti-viral properties but also has a confusing history because of many different formulations (acetate, gluconate, picolate, sulfate, etc.) and forms (pills vs lozenges). We have preliminary studies to suggest zinc supplementation might protect against COVID-19 but not direct evidence of efficacy yet. There are other reasons to take zinc, so read ahead to safely decide for yourself!

Zinc is an antioxidant and involved in many biochemical pathways in the body, including DNA synthesis and wound healing. It has long been studied for anti-viral properties against the the common cold.

Why zinc lozenges for coronavirus?

Zinc has been studied in vitro against SARS-CoV (the “first” SARS coronavirus). It has also been studied against numerous other viruses. Lozenges specifically may help zinc dissolve in close proximity to infected cells in your throat, more on that below.

But remember, in vitro studies are not easily applied to humans! They look at results in a petri dish, not in human trials.

In vitro studies of zinc against SARS-CoV showed decreased replication and decreased virulence. While they don’t constitute evidence of benefit in humans, they are a good starting point.

A family medicine physician in New York state famously sent a letter to the United States president describing his protocol for treating COVID-19 patients with a combination of hydroxychloroquine, azithromycin, and zinc. One of hydroxychloroquine’s actions is to allow zinc to enter cells. Theoretically, that combination could enhance zinc’s antiviral activity against SARS-CoV-2.

Legumes, including beans, in a bowl. Legumes are a family of foods that are rich in zinc. Why zinc lozenges when legumes are such a healthful source of zinc?
Legumes, including beans and lentils, are another good source of zinc.

Other evidence for zinc as an anti-viral?

Yes and no. We believe the mixed results are because of the zinc formulations used. There have been decades of research, but if we focus on the more recent studies:

If we look at earlier studies, the trend remains more favorable than unfavorable, though negative studies certainly exist. The pattern appears to be based on the formulation of zinc used. This is problematic when trying to compare results because of considerable variance in dose and formulation.

Why zinc lozenges instead of tablets?

Zinc lozenges dissolve in the mouth and theoretically release zinc in closer proximity to the upper airways. Viruses enter our respiratory tracts through cells in these areas. Releasing zinc in that area would theoretically be more beneficial. Fortunately, regardless of where your zinc absorbs, it will circulate throughout your entire body, but the concentration will vary.

So what about the different doses and formulations? Sounds confusing…

You’re right, zinc supplementation can be confusing. The problem is that ionized zinc shows in vitro anti-viral activity, and not all zinc supplements provide ionized zinc. In fact, some supplements don’t provide any ionized zinc! This may explain why some of the zinc studies are negative.

Inactive ingredients in supplements can prevent zinc from ionizing.

Inactive ingredients (called “excipients”) are common in supplements, often to enhance flavor, appearance, or stability. Common culprits are sugars, like mannitol and sorbitol. Tartate salts are also common additives. These added ingredients can prevent the active (ionized) form of zinc from being absorbed.

If it’s helpful, why zinc lozenges only during sickness?

The upper limit of zinc is 40mg per day. Most lozenges put you above that dose. This is one reason to use zinc lozenges for less than a week. There are serious harms from excessive zinc intake, and longer term supplementation should be done under physician supervision.

Harms from Zinc?

Side effects from excess zinc include nausea, vomiting, abdominal pain, and fatigue. More seriously, nasal zinc applications (gels and swabs) can cause permanent loss of smell. Zinc supplementation can also decrease copper and magnesium absorption.

Brazil nuts next to a bowl. Brazil nuts are a rich source of zinc. Why zinc lozenges when you can acquire zinc from whole food sources?
Brazil nuts are yet another rich plant-based source of zinc.

Why zinc lozenges instead of from food?

Getting minerals in whole food form is always my recommendation. That being said, there are two relevant reasons to consider supplementation during the COVID-19 crisis:

  • Modern diets may be deficient in zinc from:
    • Diet quality.
    • Agricultural practices that may reduce zinc content in modern foods.
  • Anti-viral properties of zinc likely require higher concentrations than are readily obtained from diet alone. Zinc lozenges can fill that gap.

Note that some individuals need to be on long term zinc supplementation for malabsorptive diseases (gastric bypass, Crohn’s disease, celiac disease, etc.). Anyone on long-term zinc supplementation should be supervised by a physician.

Zinc is also found most concentrated in meat products. Vegetarians are hence at risk of zinc deficiency. Absorption of zinc from grains and nuts can be increased by pre-soaking (this is because of phytates in those foods).

Conclusions

  • Evidence supports a role for ionized zinc in reducing duration of common colds.
    • In vitro evidence supports zinc’s activity against SARS-CoV, but we don’t have evidence against SARS-CoV-2.
  • Zinc acetate and gluconate tend to release more ionized zinc than other zinc formulations.
  • Inactive ingredients in supplements can prevent zinc from ionizing, so try to avoid any extra ingredients.
  • Lozenges, unlike capsules or tablets, may release zinc directly in the mouth where it theoretically may be more helpful.
  • Limit zinc lozenge use to less than 1 week because of the risk of excess zinc intake.
  • Always look for the ingredients of a zinc supplement to verify the dose, formulation, and presence of inactive ingredients.
  • I recommend third party testing of your zinc supplement to ensure potency and that you’re actually getting what’s printed on the label.

Even though we don’t yet have concrete evidence that zinc will prevent or reduce the severity of COVID-19, recognizing how zinc lozenges work can help you decide if supplementation is right for you. Independent of using zinc lozenges, never forget the importance of whole food sources of zinc for your baseline health!


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The information provided in this post in intended for general education. It is not medical advice. While I make every effort to provide the most up-to-date information, please note that new data is continuously becoming available and may change the conclusions I present here.

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