It will weaken the candida for sure, but might weaken you too much also. All you can do it try it and if you find you are getting too weak, then stop. You do not want to get weak, weakening the immune system too much actually helps the bad guys.
Not sure vitamins will help much. Of course it depends on what you are taking, but pill form chelated usually needs food as most times they are fat soluble.
Maybe try liquid minerals in your water whil on the fast.
Try Concentrace brand liquid minerals. I got mine at amazon.com