Study confirms high doses of vitamin D have no effect on COVID-19
There have been numerous investigations into a possible role for vitamin D in preventing both SARS-CoV-2 infections and COVID-19 complications.
These studies have drawn conflicting conclusions. Now, a study from researchers in Brazil provides a more robust answer to at least one key question: can vitamin D help prevent COVID-19 complications in particularly ill hospitalized patients? According to the results, the answer appears to be no.
The study found that high doses of vitamin D administered to hospital patients with moderate or severe COVID-19 did not affect the course of the disease.
“In vitro studies or trials with animals had previously shown that in certain situations, vitamin D and its metabolites could have anti-inflammatory and antimicrobial effects, as well as modulating the immune response,” explains Rosa Pereira, principal investigator for the study.
“We decided to investigate whether a high dose of the substance could have a protective effect in the context of an acute viral infection, reducing either the inflammation or the viral load.”
Based on the study’s results, says Pereira, “So far, we can say there’s no indication to administer vitamin D to patients who come to the hospital with severe COVID-19.”
The research appears in JAMA.
COVID-19 and vitamin D
Scientists at the University of São Paulo’s Medical School (FM-USP) in São Paulo, Brazil, conducted the randomized, double-blind, and placebo-controlled clinical trial. The researchers say this study is the first of its kind.
The team tracked the experiences of 240 volunteers receiving treatment for COVID-19 symptoms at FM-USP’s Hospital das Clínicas and the Ibirapuera Park field hospital in São Paulo City, from June to August 2020. All participants had tested positive for SARS-CoV-2 using a polymerase chain reaction test or via antibody testing.
All of them received treatment with standard COVID-19 protocols that include antibiotic and anti-inflammatory medications. The researchers then divided them into two equal groups at random.
The scientists gave participants in the first group a single 200,000-unit dose of vitamin D3 dissolved in peanut oil. They gave those in the second group unaltered peanut-oil placebos.
The design of the study was to discover whether a high dose of vitamin D was associated with a shorter hospitalization — the researchers found that it was not.
The investigation also found no evidence that vitamin D made a person less likely to be admitted to the intensive care unit or less likely to need intubation.
Vitamin D also seemed to have no effect on mortality, although Pereira cautions that a larger study with more participants is required before researchers can draw final conclusions.
More vitamin D studies needed
The study conclusively rules out vitamin D as a “magic bullet” for treating COVID-19.
Co-author Bruno Gualano, a researcher at FM-USP, says, “But that does not mean continuous use of vitamin D cannot have beneficial effects of some kind.”
Having suggested that a single high dose of vitamin D is not a solution to severe COVID-19, Pereira is now leading a new study to determine whether a vitamin D deficiency has any effect on a person’s ability to overcome SARS-CoV-2.
Pereira is also looking to establish the amount of vitamin D a person should have in their bloodstream to promote good health. This threshold will vary depending on an individual’s characteristics. Younger, generally healthy people should have at least 20 nanograms per milliliter of blood (ng/ml). Whereas for older people, for example, and those with osteoporosis, the minimum is 30 ng/ml.
Pereira says, “The ideal approach is case-by-case analysis, if necessary dosing the substance periodically by means of blood work, with supplementation if a deficiency is detected.”