This post is not intended to be medical advice. Please consult with your provider if you have symptoms of COVID-19.

Vitamin D has long been recognized as critical to bone health. This is the primary focus of a recent double blind study called VALID. It is also why Vitamin D supplementation is restricted in medical warnings: too much Vitamin D can result in a condition called hypercalcemia.

A clinical nutritionist in my BNI (Business Networking International) team touts the use of Vitamin D for immune efficacy against influenza and viral infections. Noticing that immune efficacy wasn’t part of the VALID study, I did some research on the biochemistry of Vitamin D.

There has been some direct study of the role of Vitamin D in viral infections, but the rate of infection was only marginally lower. Still, we know of winter as “cold and flu season.” There’s no good reason why that should be: unlike bacteria, viruses don’t care about the weather. So there must be some weather-related effect, and a significant one is that we spend more time during Spring and Summer outside in the sun. That promotes production of Vitamin D.

Some researchers have looked for Vitamin D receptors on immune cells, and have linked them to two systems. The first promotes antimicrobial response (the body’s ability to kill BACTERIA, which doesn’t help in viral infections). The second – AND THIS IS REALLY IMPORTANT – suppresses cytokine production that causes inflammation in association with an immune response.

So Vitamin D doesn’t help prevent infection but seems to suppress inflammation. This explains why we have “cold and flu” season during winter. The lack of sun suppresses natural production of Vitamin D, so we have strong inflammation when we get sick. This causes us to feel achy. The body is trying to keep us from going out into the cold. We still get the virus in other times of the year – it’s just that we don’t feel so miserable.

Preventing inflammation is critical in fighting pneumonia. It is the swelling that causes lungs to fill with fluid and reduces oxygen intake.

Recognizing this, the Chinese developed an aggressive protocol that suppresses the immune system to reduce inflammation when the patient is close to death from COVID-19.

Apparently the same might be possible with Vitamin D supplementation.

Note that at may elder care facilities, residents are less likely to spent time outdoors. This will cause Vitamin D deficiency and thus inflammation. Caregivers in those facilities might beneficially administer Vitamin D supplements to their residents.