The consumption of high doses of zinc and ascorbic acid (vitamin C) was not associated with an improvement in COVID-19 infections, according to a small study published today in Open JAMA network.
In an open trial of 214 people with COVID outpatients in Ohio and Florida, those who received one or both supplements had periods of symptom reduction similar to those who received standard treatment.
Over the years, scientific studies have not conclusively shown that any of the supplements can help overcome diseases such as the common cold. Since the beginning of the pandemic, however, both supplements have seen a growing market due to people’s belief that they 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 during 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 treatment for 58, 58, 48, and 50 people, respectively. Outpatients knew what treatment they were receiving.
The study ended early because it met the criteria for futility, as assessed by the Cleveland Clinic’s operational and safety monitoring board. “These interventions did not significantly reduce the duration of symptoms associated with the virus compared to the usual treatment,” conclude the researchers.
No significant effect on symptom reduction
The primary result was to see if the supplements cut the time needed to reduce symptoms by 50%. The average time it took for those who received 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 not reduced by half until 6.7 (4.4) days in the group that received only standard treatment, but the researchers found no statistical significance in any of these differences.
Outpatients measured their symptoms on a four-point severity scale, whose values were added to the total degree of symptoms. Participants registered before July 16, 2020, only rated fever / chills, shortness of breath, cough and fatigue. But, because of the updated guidelines from the Center for Disease Control and Prevention, registrants after July 16 assessed 12 symptoms that also included headache, loss of taste and runny nose / congestion. Those who were asymptomatic at the beginning of enrollment were classified as “absent” in the calculation of the time before the 50% reduction in symptoms.
No other significant benefits
The researchers also looked at the hospitalization rate, mortality and adverse effects of receiving one of the treatments or standard of care. No arm of the experiment had significantly different results, but the researchers noted that those who received ascorbic acid reported slightly more nausea, diarrhea and stomach cramps.
(Excessive vitamin C and zinc are associated with gastrointestinal intolerance, and large amounts of zinc are also related to 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 of causes unrelated to the interventions. One person had an exacerbation of chronic obstructive pulmonary disease, but there was also no relationship.
“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 has had no benefit suggests a clear lack of effectiveness,” the researchers wrote.
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, thus the potential role of other supplements in reducing the symptoms of SARS- CoV-2 cannot be completed from our study. “
Call to focus research elsewhere
In a related commentary in the journal, two American cardiologists point out the study’s limitations, including the small patient population, the focus only on outpatients and the non-blind nature of the study. These limitations, however, would most likely exaggerate the potential benefits of supplements.
Erin D. Michos, MD, MHS, of Johns Hopkins and Miguel Cainzos-Achirica, MD, PhD, MPH, of Houston Methodist wrote: “However, the study produced null results, providing more guarantees that the early completion of the trial will not hid the detection of a real benefit. “
“Given current projections that in the coming weeks the pandemic will continue to peak worldwide, along with the potential for future outbreaks, this new disappointment should not discourage further research efforts.”
These efforts, however, should focus on more promising therapies for COVID, as well as ideal policies and social interventions to combat the disease, they say.
Regarding supplements like zinc and vitamin C, Michos and Cainzos-Achirica write: “Despite the urgency, we suggest that a break may be necessary in the future. Although supplements are generally considered benign because of their over-the-counter availability, they are not necessarily free of adverse effects. “