Over the last ten or so years I have seen so many articles telling us/me that cold weather in itself does not cause colds. These articles generally point out that cold weather does not cause colds and that probably the reason we get colds in winter is simply due to the cyclic nature of viruses—and they tend to come around in the same cycle as the cold weather.
Well, based on new research and the impact of vitamin D, maybe cold winter weather has more to do with catching a cold than previously thought.
Research recently published by the University of Copenhagen indicates that our immune system is practically useless without a good supply of vitamin D available. It seems that vitamin D is vital for the immune system to do its work. Vitamin D turns the normally benign immune system T cells into virus hating and destroying warriors. Without vitamin D around to trigger this transformation in the nature of the T cells our immune system is next to useless.
The article, as published in the UK Telegraph, can be found here [Ctrl+Click to open in a new Tab].
How does this relate to cold wet weather?
Well, typically, when the conditions are cold and wet there is little or no sun—and the primary and most plentiful source of vitamin D is sunshine. So, little or no sun equates to lowered vitamin D supplies in the body, which, we now know, then equates to a less than fully effective immune system because the T cells cannot transform into virus killing warriors.
You can get relatively small doses of vitamin D from some foods, and vitamin derivatives can be obtained from vitamin pills, but by far the most effective was to dose up on vitamin D is to get some sun on your skin. You don’t need a lot of sun to get the required amount of vitamin D. When the UV rating is high, up in the 7 or 8 range, you only need about 20 minutes of sun per week on arms and face—which is less than three minutes per day. When the UV rating is low, in the range 3 to 4, you need about 2 hours of sun per week on arms and face—which is about 15 minutes per day. Apparently exposing more skin does not increase the amount of vitamin D produced by the body, which I find rather odd, but that’s what they say.
So, for someone driving to work each day in their car, providing your arms are not covered, you will likely get more than sufficient vitamin D produced by the sun’s UV rays just travelling to and from work. Even if your side windows are UV treated you will sill get enough sunlight through the untreated front windscreen reflecting off your bonnet.
Update: Looking around the Web I found this link on vitamin D as well. This link has pictures.