Consumption of high doses of zinc and ascorbic acid (vitamin C) is not related to the improvement of COVID-19 infections, according to a small study published today in JAMA Network open.
In an open-label experiment of 214 people with COVID outpatients in Ohio and Florida, those who received one or both supplements had similar symptom reduction periods as those who received standard care.
Over the years, scientific studies have not unequivocally shown that any supplement can help overcome diseases such as colds. However, since the pandemic began, both supplements have seen an increased market due to people’s belief that it can boost the immune system. The New York Times reported zinc sales of $ 134 million, and USA Today found that vitamin C sales reached $ 209 million in the first half of 2020, an increase of 76% compared to 2019.
To see how zinc and ascorbic acid can affect COVID-19, the researchers randomly assigned 10 days of zinc gluconate (50 milligrams per day), ascorbic acid (8,000 milligrams per day), both or standard care to 58, 58, 48 and 50 people, respectively. Outpatients knew what treatment they were receiving.
The study ended early because it met the uselessness criteria, as assessed by the Cleveland Clinic’s Operational and Safety Monitoring Board. “These interventions did not significantly shorten the duration of the symptoms associated with the virus compared to the usual care,” the researchers conclude.
No significant effect on reducing symptoms
The primary outcome was to see if the supplements reduced the time for symptom reduction by 50%. The mean time it took for those receiving zinc was 5.9 (standard deviation [SD], 4.9) days. Those who received ascorbic acid reported an average of 5.5 (3.7) days, and those who received both reported an average time of 5.5 (3.4).
Symptoms were first halved in 6.7 (4.4) days in the group that received only standard care, but the researchers found no statistical significance in any of these differences.
The outpatients measured their symptoms on a four-point severity scale, the values of which were then added for the total degree of symptoms. Participants entered before 16 July 2020 only rated fever / chills, shortness of breath, cough and fatigue. But due to the updated Centers for Disease Control and Prevention guidelines, those enrolled after July 16 rated 12 symptoms, which also included headaches, loss of taste, and runny nose / congestion. Those who were asymptomatic at the start of enrollment were classified as ‘missing’ when calculating the time before the 50% symptom reduction.
No other significant benefits
The researchers also looked at hospitalization rate, mortality rate and adverse effects of receiving one of the treatments or standard of care. No part of the experiment had significantly different outcomes, but the researchers note that those who received ascorbic acid reported slightly more nausea, diarrhea, and stomach cramps.
(Both vitamin C and zinc excesses are associated with gastrointestinal intolerance, and large amounts of zinc are also associated with metallic taste or dry mouth.)
Overall, 17 outpatients (7.9%) had to be hospitalized before their individual 28-day assessment was completed, and 3 (1.4%) died from causes unrelated to the interventions. One person exacerbated chronic obstructive pulmonary disease, but it was also unrelated.
“Most consumers of ascorbic acid and zinc consume significantly lower doses of these supplements. Thus, it shows that even high doses of ascorbic acid and zinc have had no benefit, indicating a lack of efficacy,” the researchers write.
They add: ‘Recent studies have also shown that vitamin D deficiency is associated with an increased risk of SARS-CoV-2 infection and an increased risk of hospitalization, so the possible role of other supplements in the declining SARS -CoV-2 symptoms not determined. from our study. ‘
Call to focus research elsewhere
In a related commentary in the journal, two American cardiologists point out the limitations of the study, including the small patient population, the focus solely on outpatients, and the non-blinded nature of the study. However, these limitations will more than likely exaggerate the potential benefits of the supplements.
Erin D. Michos, MD, MHS, of Johns Hopkins and Miguel Cainzos-Achirica, MD, PhD, MPH, of Houston Methodist write: “Yet the study yielded zero findings, providing further reassurance that the termination of the early trial did not the detection did not disguise a real benefit. ‘
“Given the current projections that the pandemic will continue to peak worldwide in the coming weeks, along with the potential for future outbreaks, this new disappointment should not discourage further research efforts.”
However, such efforts should focus on more promising therapies for COVID, as well as on optimal policies and social interventions to combat the disease.
Regarding supplements such as zinc and vitamin C, Michos and Cainzos-Achirica write: “Despite the urgency, we suggest that a little pause is needed to move forward. Although supplements are generally considered benign because of their availability without prescription, it is not necessarily free from adverse consequences. ‘