title: Response of urinary biomarkers of systemic oxidation to oral iron supplementation in healthy men.
abstract: BACKGROUND
  Urinary biomarkers are used in assessment of severe, clinical oxidative stress. Little is known, however, about their diagnostic value within the normative range.
  
  
  OBJECTIVE
  To evaluate the response of urinary thiobarbituric acid reactive substances (TBARS) and 8-hydroxy-2-deoxyguanosine (8-OHdG) as indicators of systemic oxidation in response to short-term oral iron and antioxidant supplementation.
  
  
  METHODS
  Five healthy adult men participated in the pilot study phase and 12 in the definitive intervention trial. For 7 days each, separated by 12-day washouts, the subjects received different treatment regimens, consisting of 120 mg of iron, 120 mg of iron in refined palm oil, and 120 mg of iron in palm oil combined with one of the two doses of Carotino Tocotrienol Carotene Mixed Concentrate (CTCMC). Creatinine-normalized urinary TBARS and 8-OHdG concentrations were quantified in samples taken from subjects with and without active supplementation. Temporal and correlative associations between TBARS and 8-OHdG were explored.
  
  
  RESULTS
  Daily intake of supplemental iron failed to produce any increment in urinary excretion of TBARS or 8-OHdG. However, a significant within-individual correlation between the urinary biomarkers was observed (Spearman r = 0.697, p < .0001, n = 466). Both doses of CTCMC significantly lowered urinary excretion of both oxidation indicators.
  
  
  CONCLUSIONS
  Despite the lack of effect of oral iron on the biomarkers of systemic oxidation, they show a strong and significant mutual association within the nonpathological range of oxidative stress in healthy male adults.
authors.affiliation: Center for Studies of Sensory Impairment, Aging and Metabolism (CeSSIAM), Guatemala City, Guatemala. mnorozco@uvg.edu.gt
authors.forename: Monica N
authors.initials: MN
authors.lastname: Orozco
authors.forename: Noel W
authors.initials: NW
authors.lastname: Solomons
authors.forename: Klaus
authors.initials: K
authors.lastname: Schümann
authors.forename: James K
authors.initials: JK
authors.lastname: Friel
mesh_terms: D000080242:8-Hydroxy-2'-Deoxyguanosine; D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000627:therapeutic use*; D015415:Biomarkers / Q000652:urine; D002338:Carotenoids / Q000627:therapeutic use; D018592:Cross-Over Studies; D003849:Deoxyguanosine / Q000031:analogs & derivatives* / Q000652:urine; D019587:Dietary Supplements / Q000009:adverse effects; D005296:Ferrous Compounds / Q000009:adverse effects*; D006166:Guatemala; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D008315:Malondialdehyde / Q000652:urine*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D010865:Pilot Projects; D017392:Thiobarbituric Acid Reactive Substances / Q000032:analysis*; D024508:Tocotrienols / Q000627:therapeutic use; D055815:Young Adult
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D005296:Ferrous Compounds; D017392:Thiobarbituric Acid Reactive Substances; D024508:Tocotrienols; D002338:Carotenoids; C020748:ferrous sulfate; D008315:Malondialdehyde; D000080242:8-Hydroxy-2'-Deoxyguanosine; D003849:Deoxyguanosine