Vitamin C supplementation lowers biomarkers of omega-6 lipid peroxidation - GreenMedInfo Summary
Vitamin C supplementation lowers urinary levels of 4-hydroperoxy-2-nonenal metabolites in humans.
Free Radic Biol Med. 2011 Jan 11. Epub 2011 Jan 11. PMID: 21236333
Linus Pauling Institute, Oregon State University, Corvallis, OR 97331, USA; Department of Pharmaceutical Sciences, Oregon State University.
The lack of suitable biomarkers of oxidative stress is a common problem for antioxidant intervention studies in humans. We evaluated the efficacy of vitamin C supplementation in decreasing biomarkers of lipid peroxidation in nonsmokers and in cigarette smokers, a commonly studied, free-living human model of chronic oxidative stress. Participants received ascorbic acid (500 mg twice per day) or placebos for 17 d in a double blind, placebo-controlled, randomized crossover design study. The urinary biomarkers assessed and reported herein are derived from 4-hydroperoxy-2-nonenal (HPNE) and include the mercapturic acid (MA) conjugates of 4-hydroxy-2(E)-nonenal (HNE); 1,4-dihydroxy-2(E)-nonene (DHN); and 4-oxo-2(E)-nonenol (ONO). Vitamin C supplementation decreased the urinary concentrations of both ONO-MA (p=0.0013) and HNE-MA (p=0.0213) by ~30%; however, neither cigarette smoking nor sex affected these biomarkers. In contrast, vitamin C supplementation decreased urinary concentrations of DHN-MA (3-way interaction p=0.0304) in nonsmoking men compared with nonsmoking women (p<0.05), as well as in nonsmoking men compared with smoking men (p<0.05). Vitamin C supplementation also decreased (p=0.0092) urinary total of metabolites by ~20%. Thus, HPNE metabolites can be reduced favorably in response to improved plasma ascorbic acid concentrations, an effect due to ascorbic acid antioxidant function.