Yeah, I think nutrient supplimenting during a fast is fine. Your body actually has stores of many of the vitamins and minerals it would need and uses those stores during a fast, but I don't see what supplimenting would harm. The only thing I found that I really needed to suppliment during a fast are the electrolytes (calcium, magnesium, and potassium.) Otherwise, my heart rate is sometimes a bit irregular. Anyway, I'd say go for it you feel safer that way. Peace of mind during a fast is definitly important. Best wishes!!!