Natures Aid - Vitamin C 500mg (50). Vitamin C contributes to normal collagen formation, for the normal function of blood vessels, bones, cartilage, gums, skin and teeth.. Vitamin C contributes to a normal energy-yielding metabolism, normal functioning of the nervous system, normal psychological function and the normal function of the immune system.. Vitamin C also supports the protection of cells from oxidative stress, a reduction in tiredness and fatigue, and the regeneration of the reduced form of vitamin E.. Vitamin C increases iron absorption.. Vitamin C contributes to the normal function of the immune system during and after intense physical exercise.