The use of nutraceuticals in the prophylaxis of Covid-19 continues to arouse debate in the scientific community.
Thus, a working group coordinated by Salvatore Corrao, director of the Department of Internal Medicine at Arnas Civico Di Cristina Benfratelli in Palermo, has taken the trouble to examine what is currently available in the literature on the use of nutraceuticals to control aspects of the inflammatory state related to the disease.
The use of nutraceutical supports may play a role on some aspects of the inflammatory state, thus representing a supportive strategy to control the outcomes of the ongoing pandemic. Platelet and coagulation activation, inflammation, and immunological response are the three mechanisms that play a key role in defining the course of the Covid-19 syndrome caused by the coronavirus.
Using a rigorous Cochrane methodology there was a selection of systematic reviews of controlled studies, selected for relevance to the objective set.
a literature search was performed on PubMed using specific search strings. After an evaluation of relevance and quality, the following were selected: 250 reviews on vitamin D, 75 on vitamin C, 39 on melatonin, and 77 for zinc. In the end, the included meta-analyses were.
Vitamin D showed efficacy on reducing C-reactive protein, or Pcr, with an intake of 50,000 Ui/month. In addition, this dose is in agreement with both that suggested to reduce inflammatory activation and the recommendations not to exceed 4000 IU/day to avoid toxic effects.
Regarding vitamin C, the analysis suggests that the effective dose is between 1 and 2 g per day is involved both in reducing Pcr and in improving endothelial function. Because of the impracticality of intravenous administration under community medical policy, oral intake is recommended.
With reference to melatonin, it seems to show good evidence of efficacy in reducing Pcr, Tnf, and Il 6 with a dosage between 5 and 25 mg/day. However, the correct daily dose should be adapted to age and clinical conditions, in order to avoid possible adverse effects, such as drowsiness: in our opinion it should be around 6-10 mg/day.
Literature data on zinc show a lower strength of evidence compared to other compounds. Only one systematic review was found with an intervention duration between 6 and 25 weeks. Analysis of this single study showed positive results on Pcr. The effective dosage is 50 mg/day of elemental zinc supplementation.
According to selected systematic reviews, the nutraceuticals of vitamin C, vitamin D, melatonin, and zinc have anti-inflammatory actions. Therefore, their large-scale use seems to represent a useful and feasible approach during the Covid-19 pandemic, obviously not to be understood as a substitute for vaccines and medical treatments that may be available.
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