As we have often discussed, proponents of so-called alternative medicine (SCAM), have an unfortunate tendency to mislead the public about vitamins and other supplements. Consequently, there is much uncertainty in many people’s minds. It is, therefore, all the more important to highlight new information that might counter this phenomenon.

This study tested whether high-dose zinc and/or high-dose ascorbic acid reduce the severity or duration of symptoms compared with usual care among ambulatory patients with SARS-CoV-2 infection. It was designed as a multicenter, single health system randomized clinical factorial open-label trial and enrolled 214 adult patients with a diagnosis of SARS-CoV-2 infection confirmed with a polymerase chain reaction assay who received outpatient care in sites in Ohio and Florida. The trial was conducted from April 27, 2020, to October 14, 2020.

Patients were randomized in a 1:1:1:1 allocation ratio to receive either:

  1. zinc gluconate (50 mg),
  2. ascorbic acid (8000 mg),
  3. both of these agents,
  4. standard care only.

The treatments lasted 10 days.

The primary endpoint was the number of days required to reach a 50% reduction in symptoms, including the severity of fever, cough, shortness of breath, and fatigue (rated on a 4-point scale for each symptom). Secondary endpoints included days required to reach a total symptom severity score of 0, cumulative severity score at day 5, hospitalizations, deaths, adjunctive prescribed medications, and adverse effects of the study supplements.

A total of 214 patients were randomized, with a mean (SD) age of 45.2 (14.6) years and 132 (61.7%) women. The study was stopped for a low conditional power for benefit with no significant difference among the 4 groups for the primary endpoint. Patients who received usual care without supplementation achieved a 50% reduction in symptoms at a mean (SD) of 6.7 (4.4) days compared with 5.5 (3.7) days for the ascorbic acid group, 5.9 (4.9) days for the zinc gluconate group, and 5.5 (3.4) days for the group receiving both (overall P = .45). There was no significant difference in secondary outcomes among the treatment groups.

The authors concluded that, in this randomized clinical trial of ambulatory patients diagnosed with SARS-CoV-2 infection, treatment with high-dose zinc gluconate, ascorbic acid, or a combination of the 2 supplements did not significantly decrease the duration of symptoms compared with standard of care.

This study has several limitations (and its authors are laudably frank about them):

  • Its sample size is small.
  • It has no placebo control group.
  • It is open-label.
  • Patients were not masked to which therapy they received.

The trial nevertheless adds important information about the value of using zinc or vitamin C or both in the management of COVID patients.

4 Responses to Vitamin C and/or zinc for managing COVID patients?

  • There clearly are limitations in this trial as you describe, and it is underpowered to show a small effect. A larger, placebo-controlled version would be feasible but it would require much greater numbers (perhaps thousands rather than hundreds) and would therefore be more expensive and difficult to carry out. Given that so many people are affected by Covid-19 and that both zinc and vitamin C are cheap and easy to administer this may yet be a worthwhile exercise. It is important to remember that high-dose vitamin C is not entirely free of toxicity and should not be recommended in the absence of evidence showing a benefit.

    • This ‘study’ was quickly discredited by many specialists in the field of nutrition – and NOT the so called SCAM people this forum takes delight in trashing.
      Independent comment (the list of academics and mainstream medics is too long to list here) concluded that this study was designed to fail and should not even have been published.
      So why use just two isolated nutrients to prove they don’t work in reducing covid symptoms? I think we all know the answer to that!
      My understanding as a lay person is that our immune system is extremely complex and relies on a wide variety of ‘supporting actors’ – including the following:
      Vitamin D – the active form being calcitriol produced by the liver & kidneys
      Vitamin C – from whole foods, not isolated/synthetic ascorbic acid
      Vitamin B complex
      Vitamin K2
      Omega-3 fatty acids – ALA/EPA/DHA
      and others.

      I appreciate this makes me look like a supporter of those devious SCAM practitioners and my comments will be trashed by some contributors to this forum, but I will take that risk.

      • I think that the rationale for selecting those two substances specifically is covered in the article. The Vitamin C and zinc in combination are both proposed as reducing the length of viral respiratory infection symptoms in the common cold. Of course the validity of this rationale is very much debatable but it’s there nonetheless although as we all know zinc has also been widely proposed as a subsidiary treatment for Covid-19.

      • These are all essential nutrients with well-established deficiency syndromes. They are also all toxic in higher doses. So the question becomes one of whether there is any pharmacological effect from increasing the dose over and above that required to prevent a deficiency.

        This much ought to be obvious, but as far as I can tell many people seem to take the view that if some is good then more is better. Anybody subscribing to this idea should try it next time they are cooking – I would suggest initially applying it to salt or perhaps chilli peppers.

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