I'm posting this because it is important that people, particularly dark skinned people, understand the consequences of vit D deficiency. Here's a good explainer from nutraingredients.com
Dr Davies points out there’s a very specific reason this hormone is important with the COVID-19 virus, due to the mechanism by which it enters our cells.
“It targets a protein spike on cell surfaces called ACE2 which is part of something called the renin-angiotensin system or RAS. Among other things, the RAS regulates blood pressure and inflammatory response. To use a metaphor, it’s like an engine with an accelerator and a brake. To tackle an infection the accelerator is pressed to ramp up inflammatory response to deal with the invading pathogen, but the brake also is depressed to keep things under control.
“When the invasion is dealt with, the accelerator comes off and the brake brings everything down to an idling state again. The ACE2 protein is the brake, but ACE2 is depleted as the virus replicates which effectively breaks the brake. With only an accelerator, the RAS quickly runs out of control leading to cytokine storm, out-of-control inflammation and the lungs fill up causing pneumonia. This is what kills people. Vitamin D helps here by keeping the accelerator under control by suppressing a mechanism further upstream that activates it.
“We also know that the ACE2 receptors are normally ‘invisible’ when the RAS is in its idle state, as they ACE2 receptors form a bound complex with another cell receptor. This complex comes apart during the inflammatory response when ACE2 is needed, but this also makes it visible to the virus. Vitamin D helps to keep the RAS calm so that ACE2 remains hidden.”
This is why The Ghost tries to do his running between 10AM and 2PM when the sun is strongest (except in summer) and supplements D in the fall through spring. Melanin in the skin refracts UV radiation which is why black people aren't [as] susceptible to developing skin cancer and conversely why red headed white people are VERY susceptible to developing skin cancer. However; the cost of that protection is that it takes a lot more sun exposure time to make Vit D. In Africa or other equatorial locations, this isn't usually a problem. but in extreme northern and southern latitudes, such as the northern US, Europe, the available sunlight is far less and the additional clothing worn reduces the amount of skin available to make vit. D
So if you find yourself in one of these climate zones take a Vit D supplement. Take your Zinc and if you're likely to be around a crowd of people, hit your mouth with some oil of Oregano. Not that these things will make you invincible and unable to get sick. No, it helps you keep [some] diseases from hitting you hard and may just keep you out of the hospital and the attendant bills.