The process of ageing has been repeatedly associated with increasing oxidative damage which has led to the hypothesis that reducing oxidative stress through antioxidant dietary factors may prolong lifespan. Ascorbic acid is an essential antioxidant in human diets and is widely used for supplementation. However, it is rather unclear if and to what extent ascorbic acid may affect lifespan in humans and model organisms. In our review of literature on vitamin C supplementation and its effect on lifespan in different model organisms we found that some studies suggest an increase in lifespan, other studies failed to observe any beneficial effect of vitamin C on longevity and some studies even reported a decrease in lifespan following vitamin C supplementation. Of the 14 studies included in our analysis, three were carried out in worms, four in flies and seven in rodents. The discrepancies between the studies may be related to species-specific differences, the concentration of vitamin C administered, the duration of supplementation and whether vitamin C was used alone or as part of a combined antioxidant diet. Potential underlying mechanisms through which vitamin C may influence lifespan and differences amongst species regarding the capacity to produce vitamin C endogenously are discussed.
