A randomised clinical trial of 214 patients with confirmed SARS-CoV-2 infection has demonstrated no significant difference in symptom duration between groups receiving supplementation of zinc, ascorbic acid, both, or neither.
The researchers split the patients evenly into four groups, to receive 10 days of either 50 mg of zinc gluconate, 8000 mg of ascorbic acid, both agents, or standard of care. The treatments were evaluated on the basis of how quickly each patient group reached a 50% reduction in symptoms, and as secondary endpoints, how quickly groups reached a total symptom severity score of 0, cumulative severity score at day 5, hospitalisations, deaths, adjunctive prescribed medications and any adverse reactions to the supplementation.
The study was done because there is limited evidence to suggest high doses of ascorbic acid and zinc gluconate may reduce the duration of common cold symptoms. Zinc has been said to increase polymorphonuclear cells’ ability to fight infection while ascorbic acid is an antioxidant with potential immunity-boosting effects. Unfortunately, based on the results of this study, neither supplement, individually or in combination with one another, are viable treatments to reduce symptom severity in COVID-19 patients. Indeed, the study was halted prematurely owing to the fact the patient groups exhibited no significant difference in reaching the primary endpoint or the secondary endpoints.
Patients who received ordinary care reached the primary endpoint of a 50% reduction in symptoms in an average of 6.7 days, which compared to 5.5 for those receiving ascorbic acid, 5.9 for those receiving zinc gluconate and 5.5 those receiving both supplements, which resulted in an overall P value of 0.45, indicating no significant difference.
The researchers noted several limitations, including the fact there was no placebo control group, and patients were not masked as to which treatment they were receiving. Additionally, the patients were recruited from a single health system, which may not represent the outcomes of patients in other settings. The researchers also concede a higher dose of either or both supplement may have a significant effect, but neither that, nor the effect of any other supplements were evaluated in this study. They conclude that at this time, neither supplement can be recommended to reduce symptom severity in COVID-19 patients.
