Well, the most common form of vitamin c, Ascorbic acid, is an acid. However, the body does very well at buffering to keep the body in a PH-balance.
If all the fruit and vegetables you have each day is a few apples, then you probably need some vitamins.. but I think the whole acidic thing is bogus.
Are there claims that regular vit-c supplements are supposed to be bad for you because of the acidic environment it creates, and if so, why is this acidic environment dangerous? common form of vitamin c, Ascorbic acid, is an acid. However, the body does very well at buffering to keep the body in a PH-balance.
EDIT: just found this:
http://www.springerlink.com/content/vrxt15218q871023/
haven’t read the entire thing yet, but it’s the only thing I can find that compares them. It seems ester-c is just an alternative for people who are sensitive to acidic foods. They also used high dosages (1000mg).