Importance of vitamin D

This year's cold and flu season is supposed to be more risky than usual and I am already stocking up on supplements. I am a bit of a germophobe, so I already have the disinfecting and hand washing part covered. I have the regular preventative supplements including Echinacea and Air Borne, but this year I am including zinc tablets and vitamin D. I don't usually take extra vitamin D supplements (except for what's already in my multivitamin), but I have been reading a lot about vitamin D lately and how beneficial it is to overall health.

Vitamin D is known as the "sunshine vitamin" and is critical to keeping your immune system functioning. The immune system contains vitamin D receptors. If there is not sufficient vitamin D present to bind these receptors, immune cells become weak and cannot protect the body from infection. I used to think that I would be able to get all of my vitamin D from the sun (it is produced when ultraviolet rays from sunlight strike the skin and trigger vitamin D synthesis). There are not too many foods that contain vitamin D so it's difficult to get it from food (most foods that contain vitamin D have it added, such as milk). I read recently that in the winter, it's impossible to produce vitamin D from the sun if you live north of Atlanta because the sun never gets high enough in the sky for its ultraviolet B rays to penetrate the atmosphere. So now I am supplementing with extra vitamin D!