The Short-term Effects of Antioxidant and Zinc Supplements on Oxidative Stress Biomarker Levels in Plasma: A Pilot Investigation

center dot PURPOSE: To determine if short-term Age-Related Eye Disease Study (AREDS) antioxidant and zinc supplementation affects biomarkers of oxidative stress, possibly serving as a predictor of their efficacy. center dot DESIGN: Prospective interventional case series. center dot METHODS: Nineteen subjects, 12 with intermediate or advanced age-related macular degeneration (AMID) (AREDS categories 3 or 4) and 7 non-AMID controls, were admitted to the Vanderbilt General Clinical Research Center and placed on a controlled diet for 7 days. Antioxidant and zinc supplements were stopped 2 weeks prior to study enrollment. Dietary supplementation with 500 mg vitamin C, 400 IU vitamin E, 15 mg beta-carotene, 80 mg zinc oxide, and 2 mg cupric oxide per day was instituted on study day 2. Blood was drawn on study days 2 and 7, and plasma concentrations of cysteine (Cys), cystine (CySS), glutathione (GSH), isoprostane (IsoP), and isofuran (IsoF) were determined. center dot RESULTS: Short-term AREDS supplementation significantly lowered mean plasma levels of CySS in participants on a regulated diet (P = .034). No significant differences were observed for Cys, GSH, IsoP, or IsoF. There were no significant differences between AMD patients and controls. center dot CONCLUSIONS: This pilot interventional study shows that a 5-day course of antioxidant and zinc supplements can modify plasma levels of CySS, suggesting that this oxidative stress biomarker could help predict how likely an individual is to benefit from AREDS supplementation. Further, CySS may be useful for the evaluation of new AMD therapies, particularly those hypothesized to affect redox status. (Am J Ophthalmol 2012;153: 1104-1109. (C) 2012 by Elsevier Inc. All rights reserved.)