Originally Posted by
rsvman
Zinc actually inhibits the coronavirus polymerase; this has been known for at least a decade. Zinc supplementation is one of the very few things that has ever been shown to shorten the duration of a common cold (fair warning, though: in doses high enough to really be effective, zinc side effects for many people in the trials were actually worse than the disease they were treating). Zinc may also play a role in downregulation of the over-active immune reaction to SARS-CoV-2, although I don't really know a lot about that or what its mechanism might be.
The study they were talking about was actually not a cause-effect study, but rather an ecological study. What the researchers found was that patients who had lower zinc levels at the time they came into the hospital with COVID-19 were more likely to have severe disease and more likely to die from the infection. That doesn't necessarily mean that taking zinc and raising your levels of zinc would be protective, but it is suggestive, certainly.
Another recent study showed the same finding with regard to vitamin D levels. As far as vitamin C goes, I'm not sure whether it would have any benefit. Some people think it has a general effect on helping to decrease respiratory viral infections, but studies have shown inconsistent results. There was a recent study just published in August that showed that, in one center, about 90% of patients admitted to the hospital with severe COVID-19 had undetectable levels of vitamin C in their blood. There was no control group, and it is not clear from the study whether low vitamin C levels caused patients to be more susceptible or predisposed them to worse infection, or whether, perhaps, vitamin C levels are adversely affected by infection with SARS-CoV-2. There are some bench-top studies that suggest some degree of protection from rapid replication in a chick embyo cell monolayer. It also, in general, has some mild anti-inflammatory effects. Since vitamin C is a water-soluble vitamin, you can take a bunch of it without fear of a hypervitaminosis; your body will just excrete what it doesn't need. That isn't to say that it doesn't have side effects; high doses of vitamin C cause a lot of people to have gastrointestinal distress.
Bottom line of all this? Do I think supplementation with any/all of these is worthwhile? Here are my thoughts:
Vitamin D
1) If you have had vitamin D levels drawn in the past, and know that you are vitamin D deficient, you should supplement and get your vitamin D levels into the normal range. Supplementation for low vitamin D levels can be done in many ways; you should contact your doctor to see if a really high-dose prescription vitamin D that is taken once a week would be of potential use for you.
2) If you have had vitamin D levels drawn and know your levels are good, you probably do not need to take high-dose supplements. Taking a "one-a-day" type of over-the-counter multivitamin (not the kind with megadoses of everything) is probably not a bad idea.
3) If you have never had a vitamin D level drawn, and thus have no idea whether you have adequate vitamin D levels or not, you should probably get your doctor to order a level for you, so you can see whether supplementation would be worthwhile/required.
4) If you don't know, but have no desire to be tested, taking a regular OTC multivitamin to boost levels is probably not a bad idea, as a fair proportion of the US population has low-ish vitamin D levels.
Vitamin C
1) I don't know if it would help, but it probably/certainly wouldn't hurt to have enough vitamin C in your blood. Supplementation of vitamin C, if your stomach can tolerate it, is probably not a bad idea. I don't see any role for mega-doses of vitamin C of the type advocated by Dr. Linus Pauling, but boosting your vitamin C is not going to be harmful to you.
Zinc
1) About 12% of the US population is said to be zinc deficient, with that number going up to maybe 35% among the elderly. So zinc deficiency is nowhere near as common as vitamin D deficiency. Zinc supplementation can fairly easily be overdone. Zinc supplementation causes a lot of gastric upset, cramping, diarrhea, nausea, and vomiting in many people. High levels of zinc lower your HDL (the good cholesterol). High levels of zinc can also interfere with copper metabolism. If you feel like you want to supplement your zinc levels, you should do it carefully. Adults only need about 11-12 mgs a day. Given the risks and side effects of zinc supplementation, if you decide to do zinc in any form other than just a daily multi-vitamin, you should probably discuss it with your doctor before starting, particularly if you have high cholesterol.
2) Whatever you do, do NOT use the "zinc swabs" that you inoculate directly into your nose ("Zicam"). These swabs have no proven benefit in any respiratory viral infection and carry the potential to cause anosmia (yes, loss of smell). You can see how this might cause confusion and problems in the midst of a pandemic caused by a virus that often induces anosmia as a consequence of infection. Unlike the anosmia caused by the virus, the anosmia linked to Zicam swabs has often been irreversible. This is a "drug" that has absolutely ZERO scientific evidence of efficacy, but has the potential for lifelong side effects.