Angiotensin II (Ang II) is a natural hormone that increases blood pressure. ACE2 helps in breaking down Ang II and thereby lowers its levels.
COVID-19 infection can lower the ACE2 level, which leads to excessive accumulation of Ang II. High levels of Ang II can cause ARDS and cardiac injuries. Renin, a protein released by the kidney can boost Ang II accumulation.
A 2015 study found that mice that do not have Vitamin D receptors have increased levels of Renin and Ang II. Thus, vitamin D supplement can prevent inflammatory activity of Ang II by suppressing the release of Renin in COVID-19 patients and decreasing the risk of ARDS and cardiac issues.
Thus, vitamin D can play a role in increasing the risk of developing COVID 19 infection, mortality and severity.