Avoid the Cold, Take Some Vitamin D

We've all heard about vitamin C and the immune system.

And we know our lifestyle choices directly influences our chances of getting sick.

But most of us don't know about Vitamin D and how important it is for our immune system.

Or in medical jargon:

"As the vitamin D receptor is expressed on immune cells (B cells, T cells and antigen presenting cells) and these immunologic cells are all are capable of synthesizing the active vitamin D metabolite, vitamin D has the capability of acting in an autocrine manner in a local immunologic milieu"

It's not just physiology.  There's also outcome based studies showing its importance.

"One report studied almost 19,000 subjects between 1988 and 1994. Individuals with lower vitamin D levels (<30 ng/ml) were more likely to self-report a recent upper respiratory tract infection than those with sufficient levels, even after adjusting for variables including season, age, gender, body mass and race"

In other words, Vitamin D is important for our immune systems.  And many people are deficient, especially those who spend less time outdoors in the sun.  Which often occurs in the fall, when many people get sick...