Zinc supplements for covid-19 recovery?
November 10, 2022 6:41 PM   Subscribe

A friend’s doctor recommends zinc supplements (50mg, 1x per day, along with 2000mg vitamin C) to people who are recovering from covid. This strikes me as borderline quackery even if it is probably harmless, but I am not an expert on such things. What’s the deal?

My understanding is that this is not a widely accepted practice within the medical community. The NIH seems to recommend against taking large doses of zinc as a preventative measure , and asserts that “There is insufficient evidence for the Panel to recommend either for or against the use of zinc for the treatment of COVID-19.”

Perhaps “treatment” and “recovery” are distinct and zinc is beneficial for one rather than the other, I don’t know. I figure if there were substantial support for zinc improving recovery, we’d hear about it, and it would be easy to find a reputable medical association telling people to do that. I haven’t found that, but I’m not an expert, so I’m hoping someone can tell me what the current thinking is.
posted by skewed to Health & Fitness (13 answers total) 1 user marked this as a favorite
It’s unlikely to hurt anything (unless you are one of the people who are made sick to your stomach), but you are correct that there is no evidence that it will help anything. I suppose there is a small possibility it might protect against secondary infection? It’s not going to help in the way Paxlovid, Remdesivir, Bebtelovimab or even Molnupirivir will. The best thing is to treat the infection while you have it. We have no evidence for zinc.
posted by Bottlecap at 7:09 PM on November 10, 2022

Best answer: High dose zinc will compete with copper absorption and can lead to an irreversible myeloneuropathy (breakdown of spinal cord and peripheral nerves). It doesn't take much; I have seen this happen in susceptible people who use Fixodent denture cream.
posted by basalganglia at 7:14 PM on November 10, 2022 [15 favorites]

Best answer: I wonder if it's from the limited evidence that zinc can shorten a cold. But Mayo Clinic doesn't recommend.
posted by freethefeet at 8:16 PM on November 10, 2022

Best answer: That's not a high dose of zinc, and should be fine.

The fixodent problem was usually with excessive amounts of the cream because dentures didn't fit, leading to massive over ingestion.

The zinc is pretty decent advice.
It's based on studies showing that zinc (and they should be taking more zinc, more like 80-90mg) decreases length of cold and flu symptoms, eg

Further, that those low in zinc suffer from more Covid complications:
posted by Elysum at 8:20 PM on November 10, 2022 [5 favorites]

Elysium, the article you linked says 80-90mg of zinc. Not grams!
posted by kinddieserzeit at 10:51 PM on November 10, 2022 [3 favorites]

Best answer: Another toxicologist/epidemiologist here: this is borderline quackery with a few plausible mechanisms of support, but little to no evidence to support any clinical benefit.

This is succinctly put this way in the first paper BadgerDoctor linked above. "There is a paucity of data on the efficacy of zinc therapy in the management of COVID-19 patients." From my vantage point, the best possible outlook is along the lines of "mmmaaaaaaaaybe zinc does... something, at some level, at some dose, for some people, with come clinical syndromes?" That's not enough for me to add any supplement to my intake, in part because I work in the regulatory side of supplements and I have a dim view of the industry itself (i.e. production consistency and identity is always important, but if a clinical beefit relies on a very standard and consistent access to a supplement, I'm not confident that I'd get it reliably from commercial vendors).

This is jsut one of those areas where people disagree about what the existing data means so there's no real silver bullet to end the discussion yet. We may not ever get that level of certainty.
posted by late afternoon dreaming hotel at 12:55 AM on November 11, 2022 [9 favorites]

@kinddieserzeit yes? And the amount the friends Dr has recommended is also in micrograms?
It says 50mg in the post above, so take 1 & 1/2 or 2 a day to be closer to the amount recommend in the top study.

That seems fine relative to the RDI for zinc.
posted by Elysum at 1:07 AM on November 11, 2022

Elysum, your earlier post here said people should be taking 80-90g, which is what kinddieserzeit was pointing out was incorrect.
posted by tubedogg at 2:30 AM on November 11, 2022 [5 favorites]

Best answer: Personally, I don't see ANY evidence zinc has any effect on COVID, not that zinc has much effect on the common cold anyway. Meta analysis of 20+ studies done in 2021 shows that "at best" zinc can reduce sick period by 2 days, and reduce symptom severity slightly, but that's about it. There's really no evidence it has any effect on COVID, before, during, or after other than "it's kinda related to a cold, sorta..."

Don't over do it, but otherwise, I guess it wouldn't hurt.
posted by kschang at 3:46 AM on November 11, 2022

Best answer: I think it's worth unpacking what you mean by "quackery". I think of stuff like snake oil, and doing harm by taking water (homeopathic treatments) instead of known effective treatments.

That is not what this is. Zinc supplements have a wide body of research showing a) that it is safe if used as directed and b) that it can reduce the duration and severity of cold-like symptoms. It is true there is a paucity of data about zinc and Covid. Good research takes time and this is all still very new. And reasonable people can disagree for now over whether it is likely to help anyone through Covid recovery. We even see two relevant experts above disagreeing on what to take away from the same research. And that's ok!

Overall, we can't say this advice is determined by a broad body of specific evidence for this use. But lots of medical experts are ok with suggesting something that is harmless and might help. I'm a biologist but not that kind of biologist. My take is: take the zinc or don't, but don't call this poor doctor a quack over it.
posted by SaltySalticid at 5:05 AM on November 11, 2022 [11 favorites]

Response by poster: Thanks for the input everyone. I agree that I shouldn’t throw around the quackery term, this is not a doctor I’ve spoken to personally and don’t know the full context of their statements.
posted by skewed at 10:12 AM on November 11, 2022

It's also possible that the doctor thinks that zinc is unlikely to help, but is recommending it for placebo reasons. As far as it goes, that would seem reasonable to me — there is inconclusive research suggesting it could possibly help, and pretty clear evidence that it won't hurt if taken as directed. Much better than, for instance, doctors prescribing antibiotics to people with viral illnesses for placebo reasons, which is a thing that happens that absolutely should not, IMO.
posted by wesleyac at 10:17 AM on November 11, 2022

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