I’ve done a bunch of long fasts and take all 7 electrolytes including bicarbonate. Balanced Electrolytes are a must for a higher energy fast.
I vitamin up as well days before and get a good dividable multi vitamin. I get really nauseas taking a full multi vitamin on long fasts. I usually break it half and take at different times.
Most vitamins are lipid soluble except your b vitamins that do also get flushed on a long fast. So get some excellent methylated B vitamins as well. Good luck.