title: Potential problems of ascorbate and iron supplementation: pro-oxidant effect in vivo?
abstract: The comparison was undertaken between the effects of ascorbate versus ascorbate plus iron supplementation on DNA damage. Twenty healthy subjects with initial levels of plasma ascorbate of 67.2 +/- 23.3 micromol/l were randomly assigned to and cycled through one of three supplementation regimes: placebo, 260 mg/d ascorbate, 260 mg/d ascorbate plus 14 mg/d iron for 6 weeks separated by 8-week washout periods. Supplementation did not cause a rise in total oxidative DNA damage measured by GC-MS. However, a significant decrease occurred in levels of 8-oxo-7,8-dihydroguanine by ascorbate supplementation and 5-hydroxymethyl uracil by both ascorbate and ascorbate plus iron supplementation, relative to the pre-supplemental levels but not to the placebo group. In addition, levels of 5-hydroxymethyl hydantoin and 5-hydroxy cytosine increased significantly, only relative to pre-supplementation, by ascorbate plus iron treatment. No compelling evidence for a pro-oxidant effect of ascorbate supplementation, in the presence or absence of iron, on DNA base damage was observed.
authors.affiliation: Wolfson Centre for Age-Related Diseases, GKT School of Biomedical Sciences, King's College London, St. Thomas' Street, London, SE1 9RT, United Kingdom.
authors.forename: A R
authors.initials: AR
authors.lastname: Proteggente
authors.forename: A
authors.initials: A
authors.lastname: Rehman
authors.forename: B
authors.initials: B
authors.lastname: Halliwell
authors.forename: C A
authors.initials: CA
authors.lastname: Rice-Evans
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001205:Ascorbic Acid / Q000097:blood / Q000494:pharmacology*; D018592:Cross-Over Studies; D004247:DNA / Q000187:drug effects* / Q000378:metabolism; D004249:DNA Damage; D004032:Diet; D019587:Dietary Supplements / Q000009:adverse effects; D004311:Double-Blind Method; D004435:Eating; D005260:Female; D006801:Humans; D007501:Iron / Q000097:blood / Q000494:pharmacology*; D008297:Male; D008875:Middle Aged; D016877:Oxidants / Q000494:pharmacology*
chemical_list: D016877:Oxidants; D004247:DNA; D007501:Iron; D001205:Ascorbic Acid