Science. 2006 Mar 24;311(5768):1770-3.
- They shift further North or South?
- They move into cities?
If we get colds and flu due to getting cold, then why is it that people who work the skifields, including pro skiers always seem to be very healthy?
Why is it that flus and colds are worst during winter, despite the fact that these bugs are present in populations year round?
Why is it that flu outbreaks in the tropics are worst during the rainy season?
The answer may be due to my pet topic for some years now: Vitmain D deficiency which is present in populations and worst during winter. We are learning all the time just why the body produces massive amounts of this vitamin when the skin is exposed to sunlight. The latest finding is that it may exert a powerful antibiotic effect on both bacteria and viruses.
When people move North or South and into cities, they tend to get much less year-round sunlight and dark-skinned people are poorly adapted for low sunlight. During the rainy season in the tropics, there may be no sunlight for weeks on end. This is exacerbated nowadays in many lands by air pollution that blocks UV. People who work on skifields get constant exposure to high levels of UV radiation, thus producing vitamin D despite the cold.
Commonsense tells us that the human body must be making Vitamin D for very good reasons. The list of good reasons grows longer by the day.