Short-term antioxidant supplementation reduces oxidative stress in elderly patients with type 2 diabetes mellitus - A pilot study

Abstract

Aims: The aim of this pilot study was to determine what dose of which antioxidants might be studied in clinical trials by assessing the impact of vitamin (C and E) supplementation on markers of oxidative stress and LDL subfractions in patients with type 2 diabetes mellitus. Methods: Nine elderly patients with type 2 diabetes took a moderate dose combination of vitamins C (500 mg) and E (400 IU) for 4 weeks. Following a 4 week washout, the patients had a further 4 weeks of supplementation with a higher dose combination of vitamins C (1000 mg) and E (800 IU). Blood was sampled pre- and post-supplementation for vitamin E by high-performance liquid chromatography (HPLC), total antioxidant capacity by enhanced chemiluminescence, total cholesterol and lipid hydroperoxides by colour spectrophotometry and LDL subfraction profile by disc polyacrylamide gel electrophoresis. Results: Vitamin E was increased, after the moderate dose combination (59.8 ± 6 versus 36.4 ± 4 μmol/L, p < 0.001) and increased further by the higher dose (72.7 ± 11 versus 30.8 ± 5 μmol/L, p < 0.001). Total antioxidant capacity was significantly increased above baseline after both doses (508.2 ± 33 versus 436.4 ± 31, p < 0.01 (moderate); 519.3 ± 48 versus 440.8 ± 34 μmol/L trolox eq., p < 0.01 (high)). Lipid hydroperoxides were reduced more after the moderate dose combination than after the high dose (6.1 ± 1 versus 12.1 ± 2, p < 0.01; 8.0 ± 1 versus 11.6 ± 1 μmol/L, p < 0.05). LDL subfraction score showed a non-significant reduction after both periods of supplementation. Conclusions: This study has demonstrated that supplementation with modest doses of the aantioxidant vitamins C and E can significantly increase antioxidant defences and reduce oxidative damage in elderly patients with type 2 diabetes. Copyright © 2002 John Wiley & Sons, Ltd.