Why Vitamin C, helps fight infections?

Question

Why Vitamin C, helps fight infections?

Answer 1

Linus Pauling, the Nobel-winning biochemist, hypothesized that it would. Subsequent study has failed to show significant benefit, but since vitamins are food supplements, the FDA can't regulate health claims on advertising, so the myth has persisted.

Answer 2

Vit C is a mild anti-biotic. Ascorbic acid has been used as a food preservative, too.

Answer 3

It is claimed to help with the common cold. Certainly an acute shortage [aka scurvy] hinders your ability to fight any infection.

But I have heard no claim that Vitamin C helps fight bacteria or fungi - only some viruses.

It is not clear to me that it actually does, and I think the clinical evidence is equivocal.