Someone recommended that Jenna drink "Smart Water" so I read about it. Smart Water by Glaceau is vapor distilled water with electrolytes added (magnesium, potassium and calcium) designed for rapid hydration without calories or sodium. It works like Gatorade, but without the sugar or flavoring. Maybe she will try some.
http://www.glaceau.com if you want to read more, although not much info on how much potassium is added.