I didn't take anything myself, but I'm not deficient at all and from what I understand, you don't really need them. I know people recommended I did(read= positive and negative critics of fasting, read= ignorant unwashed masses), but I ignored them. Whether it has any bearing on how your fast goes, that would be a question for Mighty Sun Tzu or Chris or perhaps just any faster who is more experienced than me with the concept. As it were, I think I read something that either they don't absorb without food or that you really need them to work through food, or both.
You had asked earlier if I've managed to stay off cigarettes. I have since I started the fast, which means I haven't smoked or really wanted to much since I started my fast.