“There’s no randomized controlled trial for sure, and that’s the gold standard,” Clifford Rosen, MD told Medscape Medical News, and “the observational data are so confounded, it’s difficult to know.”
However, it is important to have some vitamin D, whether it is from diet or supplementation.
There are studies that suggest vitamin D supplementation will reduce the severity of the symptoms and there are studies to indicate that there is no benefit related to vitamin D consumption. That doesn’t mean vitamin D won’t help – it means it has not been proven to help by the scientific community. Considering adequate vitamin D exposure is generally a healthful thing, people should consider dietary intake, especially for those who have been quarantined or social distancing inside their homes.
According to Medscape news, “observational data comparing outcomes from various countries suggest inverse links between vitamin D levels and the severity of COVID-19 responses, as well as mortality, with the further suggestion of an effect of vitamin D on the immune response to infection.”
But other studies question such a link, including any association between vitamin D concentration and differences in COVID-19 severity by ethnic group.
“…while some researchers and clinicians believe people should get tested to see if they have adequate vitamin D levels during this pandemic — in particular frontline healthcare workers — most doctors say the best way to ensure that people have adequate levels of vitamin D during COVID-19 is to simply take supplements at currently recommended levels.”