Vitamin C and genomic stability

Vitamin C, a water-soluble glucose derivative, has considerable antioxidant activity in vitro, in part because of its ease of oxidation and because th e semidehydroascorbate radical derived from it is of low reactivity. Vitami n C in vivo is an essential cofactor for a range of enzymes involved in div erse metabolic pathways, but much recent Literature has focused on its anti oxidant effects. Consumption of foods rich in Vitamin C (fruits and vegetab les) is associated with decreased risk of cardiovascular disease, of many t ypes of cancer and possibly of neurodegenerative disease, but the extent to which Vitamin C contributes to these effects Is uncertain. Data using biom arkers of oxidative damage to DNA bases have given no compelling evidence t o date that ascorbate supplements can decrease the levels of oxidative DNA damage in vivo, except perhaps in subjects with very low Vitamin C intakes, Similarly: there is no conclusive evidence from studies of strand breaks, micronuclei, or chromosomal aberrations for a protective effect of Vitamin C. There is limited evidence that supplements of Vitamin C might have benef icial effects in disorders of vascular function, and that diet-derived Vita min C may decrease gastric cancer incidence in certain populations, but it is not clear whether it is the antioxidant or other properties of ascorbate that are responsible for these two actions. (C) 2001 Elsevier Science B.V. All rights reserved.