Vitamin C elevates red blood cell glutathione in healthy adults.
We examined the effect of supplemental ascorbic acid on red blood cell glutathione. Subjects consumed self-selected vitamin C-restricted diets, and, under double-blind conditions, ingested placebo daily for week 1 (baseline), 500 mg L-ascorbate/d for weeks 2-3, 2000 mg L-ascorbate/d for weeks 4-5, and placebo daily for week 6 (withdraw). Mean red blood cell glutathione rose nearly 50% (P < 0.05) after the 500-mg period compared with baseline, and the changes from baseline for individual subjects ranged from +8% to +84%. However, the increases in plasma vitamin C and red blood cell glutathione were not correlated (r = 0.22). At the 2000-mg dosage, mean red blood cell glutathione was not significantly different from the value obtained at the 500-mg dosage. After the placebo-controlled withdraw period, red blood cell glutathione did not differ from baseline. These data indicate that vitamin C supplementation (500 mg/d) maintains reduced glutathione concentrations in blood and improves the overall antioxidant protection capacity of blood.
Johnston
C S
CS
Department of Family Resources and Human Development, Arizona State University, Tempe 85287.
Meyer
C G
CG
Srilakshmi
J C
JC
D000293:Adolescent; D000328:Adult; D001205:Ascorbic Acid / Q000008:administration & dosage / Q000494:pharmacology*; D004032:Diet; D004311:Double-Blind Method; D004912:Erythrocytes / Q000187:drug effects* / Q000378:metabolism; D005260:Female; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D008297:Male; D008875:Middle Aged
D005978:Glutathione; D001205:Ascorbic Acid