Zinc and Vitamin C fell short in a clinical trial after researchers found they made no significant difference in easing the duration of coronavirus symptoms.
Findings from the Cleveland Clinic were published in JAMA Network on Friday, drawing on results from April 27 to Oct. 14, when 214 coronavirus patients in Ohio and Florida outpatient care sites were given either 50 milligrams of high-dose zinc to be taken at night, 8,000 milligrams of Vitamin C to be taken several times throughout the day with meals, a combination of the two or standard care over a 10-day period.
These patients, averaging about 45 years old, were at home, and answered virtual surveys about their symptoms, any adverse effects, hospitalizations and other medications. Any patient that required hospitalization was considered a treatment failure, researchers said. Data shows most of the patients were experiencing mild symptoms, with very few suffering severe cases.
Patients reached a 50% reduction in symptoms after 6.7 days with usual care, 5.5 days when treated with Vitamin C, 5.9 days with zinc and 5.5 days for the combo treatment.
“These findings suggest that treatment with zinc, ascorbic acid, or both does not affect SARS-CoV-2 symptoms,” study authors wrote.
The scientists ended the trial early because the supplements weren’t having any effect. Study authors noted four serious events, including three deaths due to COVID-19, not believed to be tied to the treatment. More patients receiving Vitamin C reported side effects like nausea, diarrhea and cramps.
The study authors said there has been “inconsistent” evidence for zinc and Vitamin C as a beneficial treatment for colds.
The Cleveland Clinic study authors noted that zinc is known to help cells fight infection and boost the immune system, and Vitamin C “is an antioxidant that may play a role in immune response,” though the role of Vitamin C and zinc in treating coronavirus is less clear.
“However, based on the current study, these supplements cannot be recommended to reduce symptom morbidity in such patients,” the study reads. “High-dose zinc gluconate, ascorbic acid, or both supplements did not reduce SARS-CoV-2 symptoms. Most consumers of ascorbic acid and zinc are taking significantly lower doses of these supplements, so demonstrating that even high-dose ascorbic acid and zinc had no benefit suggests clear lack of efficiency