Dietary supplementation with different vitamin C doses: no effect on oxidative DNA damage in healthy people.
BACKGROUND
Antioxidants are believed to prevent many types of disease. Some previous studies suggest that dietary supplementation with vitamin C results in a decrease in the level of one of the markers of oxidative damage-8-oxoguanine in the DNA of peripheral blood mononuclear cells (PBMC). AIM OF TRIAL: To investigate the effect of different dose levels of dietary supplementation with vitamin C on oxidative DNA damage.


METHODS
A randomised double-blind placebo-controlled trial was carried out using three different levels (80, 200 and 400 mg) of dietary vitamin C supplementation in a healthy population of 160 volunteers; supplementation was for a period of 15 weeks followed by a 10 week washout period. Peripheral blood samples were obtained every 5 weeks from baseline to 25 weeks.


RESULTS
An increase in PBMC vitamin C levels was not observed following supplementation in healthy volunteers. There was no effect found on 8-oxoguanine measured using HPLC with electrochemical detection for any of the three supplemented groups compared to placebo. 8-oxoadenine levels were below the limit of detection of the HPLC system used here.


CONCLUSIONS
Supplementation with vitamin C had little effect on cellular levels in this group of healthy individuals, suggesting their diets were replete in vitamin C. The dose range of vitamin C used did not affect oxidative damage in PBMC DNA.
Herbert
K E
KE
Dept. of Cardiovascular Sciences, University of Leicester Robert Kilpatrick Building, Leicester Royal Infirmary, Leicester LE2 7LX, UK.
Fletcher
S
S
Chauhan
D
D
Ladapo
A
A
Nirwan
J
J
Munson
S
S
Mistry
P
P
D000293:Adolescent; D000328:Adult; D000975:Antioxidants / Q000378:metabolism / Q000494:pharmacology*; D001205:Ascorbic Acid / Q000097:blood / Q000494:pharmacology*; D002851:Chromatography, High Pressure Liquid; D018592:Cross-Over Studies; D004249:DNA Damage / Q000187:drug effects*; D019587:Dietary Supplements; D004305:Dose-Response Relationship, Drug; D004311:Double-Blind Method; D005260:Female; D006147:Guanine / Q000031:analogs & derivatives* / Q000032:analysis / Q000378:metabolism; D006801:Humans; D007963:Leukocytes, Mononuclear / Q000187:drug effects* / Q000378:metabolism*; D008297:Male; D008875:Middle Aged; D010084:Oxidation-Reduction; D018384:Oxidative Stress / Q000187:drug effects
D000975:Antioxidants; C024829:8-hydroxyguanine; D006147:Guanine; D001205:Ascorbic Acid