"THE NATIONAL INSTITUTE FOR HEALTH AND CARE EXCELLENCE (NICE) ESTIMATE THAT 1 IN 5 ADULTS AND 1 IN 6 CHILDREN IN ENGLAND ALONE MAY HAVE LOW VITAMIN D STATUS."
Vitamin D is the collective name for a group of chemicals but in short, exposure to UV light allows one variant, D3, to be made in the skin, which is then transported to the liver where it is turned into calcitriol, the active form of the vitamin. Therefore, sunlight is vital when it comes to our vitamin D status, and around 15 minutes of direct exposure, ideally between 10am and 2pm, and without blocking UV protection for enough vitamin D production to take place in the skin.
It’s not enough to have just the face in the sun, ideally the arms, legs and even some torso would be exposed too for optimal effect. The NHS suggest that this is not a problem from April until September, but in reality, sunlight is not guaranteed in this part of the world, even in the summer months.
The focus on vitamin D is quite understandable given its involvement in supporting the immune system, notably respiratory conditions, not unlike COVID. Vitamin D plays many roles including potentially enhancing the activity of T cells, which activate other immune cells in part by producing cytokines, messengers that call in various mediators of inflammation. In the short-term inflammation is an important part of repair and healing, but in the longer-term cytokines may continue to trigger an inflammatory response in the longer term, known as hyperinflammation, in which tissue damage can occur. In some cases, this can be fatal.
It has been suggested that supplementing vitamin D may play a significant role in reducing the incidence and severity of respiratory infections, yet studies have produced inconsistent results.