Vitamin D may help prevent lung injury and pneumonia by restoring homeostasis to the renin-angiotensin system.

“this data suggests that vitamin D may play a very important role in protecting against acute respiratory distress syndrome acute lung injury and it may do so by regulating the Rena and angiotensin system in cases where the ACE 2 levels are decreased which has been shown to happen in acute lung injury it's been shown than with SARS Cove one it may then help rebalance that ace to level by increasing the levels in that situation”

“when the active form of vitamin D called calcitriol was administered before lung injury in animals it protected them from acute lung injury by helping to balance the Rena and angiotensin system it did this by increasing ACE two levels and down regulating Rena”

“the vitamin D increased ace two receptor levels only in conditions of acute lung injury where ace 2 levels decreased when vitamin D was given to control animals that did not have an induced lung injury it did not cause or increase ace 2 receptor levels this means that vitamin D is normalizing the ACE 2 receptor levels in situations where it is down regulated or dysregulated”

“This is supported by data from animal studies where acute lung injury decreases ACE2 receptor levels and this exacerbates disease severity, but vitamin D increases ACE2 levels. And this was shown to protect against acute lung injury.”

“So that's been shown with SARS-CoV-1. And what happens when the ACE2 gets down-regulated, acute lung injury gets really bad. And so there's been some animal studies that have found, for example, if you high-dose with the active form of vitamin D, the animals, and then you cause acute lung injury, ACE2 goes down, acute lung injury goes up in the placebo group, but the vitamin D group, it normalizes the ACE2 levels.”