What the research on Vitamin D and immune health?
There has been a lot of research to suggest that having good vitamin D levels is helpful in the protection against RNA virus infections like the common cold, seasonal flu. Studies also suggest that vitamin D helps to fight illness in the least destructive way. People who become really sick from COVID-19 pneumonia are generally suffering from something called a cytokine storm. A cytokine storm is a disproportionate overreaction of the immune system that causes significant organ damage and can in some cases lead to death. The good news is that normal vitamin D levels have been associated with a reduction in cytokine storms. Though this is by no means conclusive, even an association like this must surely be a good thing.
However, despite the existing evidence of the link between vitamin D and immune health, in July of this year, the Scientific Advisory Committee on Nutrition (SACN) concluded that studies on using vitamin D for treating or preventing chest infections showed insufficient evidence to recommend supplementing with it. Based on this advice, the National Institute of Clinical Excellence (NICE) then suggested that there is no evidence to support taking vitamin D supplements to specifically prevent or treat coronavirus.
Interestingly, since the SACN conclusion a series of recently published studies specifically looking into Covid-19 concluded that vitamin D indeed can reduce the risk of developing COVID-19 as well as decrease the severity of the illness. In one study from the University of Chicago for example, 489 patients at the hospital were studied, it was observed that those who were deficient in vitamin D were twice as likely to test positive for Corona virus that those with normal levels of vitamin D. Another pilot randomized European clinical trial found that oral supplementation reduced the risk of ICU admissions by 93%.