If you live in the PNW or a big city with the cavernous streets, you should worry about vitamin D. Here in the south, most of us don't have to worry about that end of the spectrum. The only way to avoid sun exposure is to stay inside your house all day every day. Even in the car, we are exposed to sun. I got a suntan on my left arm from driving from home in NW Arkansas to Austin, TX, in March. The tinted window was UP the whole time. So, there are lots of factors to consider about whether you should supplement or not.

There's also the study that says vitamin D supplementation may be immunosuppressant.

http://www.sciencedaily.com/releases...0125223302.htm

I think all things in moderation, including exposure to the sun.

Karen