title: Association of selenium status and blood glutathione concentrations in blacks and whites.
abstract: Selenium deficiency has been linked with increased cancer risk and, in some studies, selenium supplementation was protective against certain cancers. Previous studies have suggested that selenium chemoprevention may involve reduced oxidative stress through enhanced glutathione (GSH). Our objectives were to examine the relationships between selenium and GSH in the blood and the modifying effects of race and sex in free-living adults and individuals supplemented with selenium. Plasma selenium concentrations and free and bound GSH concentrations and γ-glutamyl cysteine ligase (GCL) activity in the blood were measured in 336 healthy adults (161 Blacks, 175 Whites). Plasma selenium and blood GSH were also measured in 36 healthy men from our previously conducted placebo-controlled trial of selenium-enriched yeast (247 μg/day for 9 mo). In free-living adults, selenium concentrations were associated with increased blood GSH concentration and GCL activity (P < 0.05). Further, selenium was significantly higher in Whites than in Blacks (P < 0.01). After 9 mo of supplementation, plasma selenium increased 114% in Whites and 50% in Blacks (P < 0.05), and blood GSH increased 35% in Whites (P < 0.05) but was unchanged in Blacks. These results indicate a direct association between selenium and GSH in the blood of both free-living and selenium-supplemented individuals, with race being an important modifying factor.
authors.affiliation: Department of Public Health Sciences, Penn State Hershey Cancer Institute, Penn State University College of Medicine, Hershey, Pennsylvania 17033, USA. jrichie@psu.edu
authors.forename: John P
authors.initials: JP
authors.lastname: Richie
authors.forename: Joshua E
authors.initials: JE
authors.lastname: Muscat
authors.forename: Irina
authors.initials: I
authors.lastname: Ellison
authors.forename: Ana
authors.initials: A
authors.lastname: Calcagnotto
authors.forename: Wayne
authors.initials: W
authors.lastname: Kleinman
authors.forename: Karam
authors.initials: K
authors.lastname: El-Bayoumy
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D000975:Antioxidants / Q000008:administration & dosage; D001682:Biological Availability; D015415:Biomarkers; D044383:Black People; D019587:Dietary Supplements; D004311:Double-Blind Method; D005260:Female; D005978:Glutathione / Q000097:blood* / Q000187:drug effects; D006801:Humans; D008297:Male; D008875:Middle Aged; D009518:New York; D018384:Oxidative Stress; D012643:Selenium / Q000008:administration & dosage* / Q000097:blood*; D012907:Smoking; D044465:White People; D055815:Young Adult; D001741:Black or African American
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D005978:Glutathione; D012643:Selenium