We are supposed to take vitamins? I have never taken them at home of on the trail. A few years ago I did try some energy drinks, once!… filled up all my water bottles with the stuff and then had to poop — opps, no water to wash my hands. Good thing my friend Wisner was around with some extra water :) Anyway the stuff tasted awful, so I went back to plain ol’ water.
Some folks who do multi-month thru-hikes seem to be okay just eating junk food or whatever they can find in gas stations or convenience stores.
I suppose vitamins might be helpful, I have no proof they are not.