The effects of high-dose vitamin E supplementation on biomarkers of kidney injury, inflammation, and oxidative stress in patients with diabetic nephropathy: A randomized, double-blind, placebo-controlled trial

Abstract

Limited data are available that evaluated the effects of high-dose vitamin E supplementation on biomarkers of kidney injury, inflammation, and oxidative stress in patients with diabetic nephropathy (DN). This study was conducted to evaluate the effects of high-dose vitamin E supplementation on biomarkers of kidney injury, inflammation, and oxidative stress in patients with DN. This randomized double-blind placebo-controlled clinical trial was carried out among 60 patients with DN. Patients were randomly allocated into two groups to take either 1200 IU/d of vitamin E supplements (n=30) or placebo (n=30) for 12weeks. Fasting blood samples were obtained at the onset of the study and after 12-week intervention to assess biomarkers of kidney injury, inflammation, and oxidative stress. After 12weeks of intervention, compared with the placebo, vitamin E supplementation resulted in a significant increase in serum vitamin E levels (+42.3±13.4 vs -0.8±0.8nmol/mL, P<.001) and a significant decrease in urine protein (-6.8±4.3 vs -1.0±8.0mg/dL, P=.001) and protein-to-creatinine ratio (-0.2±0.1 vs 0.0±0.1, P<.001). In addition, a significant reduction in serum tumor necrosis factor-α (-35.4±34.9 vs+5.6±6.2ng/L, P<.001), matrix metalloproteinase-2 (-556.7±485.9 vs+60.4±53.7ng/mL, P<.001), matrix metalloproteinase-9 (-1461.5±1456.0 vs+225.7±488.2ng/L, P<.001), malondialdehyde (-0.9±0.5 vs+0.3±0.4μmol/L, P<.001), advanced glycation end products (-1832.2±1941.6 vs+177.3±324.1 arbitrary unit, P<.001), and insulin concentrations (-0.5±2.7 vs+0.7±1.0 μIU/mL, P=.03) was seen after the administration of vitamin E supplements compared with the placebo. Supplementation with vitamin E had no significant effects on other biomarkers of kidney injury, fasting plasma glucose, and insulin resistance compared with the placebo. Overall, our study demonstrated that oral high-dose vitamin E supplementation for 12weeks among DN patients had favorable effects on biomarkers of kidney injury, inflammation, and oxidative stress.