In regards to Harriet's comment that Vit D isn't really a steroid, like my doctor said it was yesterday, I googled some things and ended up with this.
From Wikipedia (paraphrasing here) the vit. word is derived from the compound word vitamine which is from vital and amine. The doctor quoted something like the vitamine word in his explaination that vD is a steroid. Well, this guy went from one thing to the next so fast I couldn't discuss... anyway I believe he was trying to tell me it was ok to take a steroid because even VD is a steroid. Bad analogy in my book, the stuff he shot me with and gave me in pills is chemicals.
Anyway, here's a very interesting link to the basis and definition of vitamins.
www.en.wikipedia.org/wiki/Vitamin
I hope that link works. It is just one page which I found interesting and comes from a published book which comes up if curser is put over the right spot.