The effect of vitamins C and E on biomarkers of oxidative stress depends on baseline level.

Block G, Jensen CD, Morrow JD, Holland N, Norkus EP, Milne GL, Hudes M, Dalvi TB, Crawford PB, Fung EB, Schumacher L, Harmatz P
Free Radic Biol Med. 2008 45 (4): 377-84

PMID: 18455517 · PMCID: PMC2750000 · DOI:10.1016/j.freeradbiomed.2008.04.005

Oxidative stress is elevated in obesity, and may be a major mechanism for obesity-related diseases. Nonsmokers (n=396) were randomized to 1000 mg/day vitamin C, 800 IU/day vitamin E, or placebo, for 2 months. Treatment effect was examined in multiple regression analyses using an intention-to-treat approach. Vitamin C (P=0.001) and vitamin E (P=0.043) reduced plasma F2-isoprostanes. In the overall sample, changes from baseline were +6.8, -10.6, and -3.9% for placebo, vitamin C, and vitamin E groups, respectively. However, a significant interaction with baseline F2-isoprostane was found. When baseline F2-isoprostane was >50 microg/mL, vitamin C reduced F2-isoprostane by 22% (P=0.01). Vitamin E reduced it by 9.8% (P=0.46). Below that cut point, neither treatment produced further reductions. F2-isoprostane>50 microg/mL was strongly associated with obesity, and was present in 42% of the sample. Change in malondialdehyde concentration was minimal. These findings suggest a role for vitamin C in reducing lipid peroxidation. Future research on effects of vitamins C or E on plasma F2-isoprostane should limit participants to those with baseline levels >50 mug/mL. Further studies are needed to establish whether treatment with vitamins C or E in persons with concentrations above that cut point could slow the development of cardiovascular disease.

MeSH Terms (13)

Adult Ascorbic Acid Biomarkers F2-Isoprostanes Female Humans Male Middle Aged Obesity Oxidative Stress Placebos Regression Analysis Vitamin E

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