Has anyone got study/s that indicates over 500mg of vit c is pro oxidant?

controv subject.....and id doubt wed ever get to the bottom of this one...

interestingly there's IV protocols out there that would push in up to 10g Vit C (but in the Sodium Ascorbate form).

I think that when taking Vit C in 500mg+ doses Vit E is needed (natural mixed Vit E). afaik this allows better absorption of the Vit C thus preventing unabsorbed Vit C from "floating about" making a nuisance of itself. I take 1g Vit C with 400mg Vit E after training with first solid meal as an example. In a day I probably consume <=500mg of Vit C spread out with other supps.

Most vits & minerals work synergistically with each other and so are often best taken together.

There's a study from 1998 that showed some DNA damage with 500mg doses. The study is controversial and further studies have mixed reviews. A later study showed no damage with 260mg doses. What is more certain is that in the presence of iron ascorbic acid tends to turn pro-oxidative, results are from in vitro or animal models though. So, what to do? Spread the doses, avoid taking it with iron supplements (or avoid taking iron since vitamin C increases its bioavailability) and take it with other anti-oxidants, vitamin E is very good to take with vitamin C.

Some links:

http://jn.nutrition.org/cgi/content/full/134/2/435
http://www.fasebj.org/cgi/content/full/13/9/1007#T2