The Effect of Quercetin Supplementation on Oxidative Stress, Glycemic Control, Lipid Profile and Insulin Resistance in Type 2 Diabetes: A Randomized Clinical Trial

Background: diabetes mellitus (dm) is closely associated withreduction of antioxidant defense system. in the present study, weinvestigated the antioxidant effect of quercetin supplementationon the glycemic control, lipid profile and oxidative stress indicesin patients with type 2diabetes.methods: forty seven patients with type 2 diabetes, aged 30-60years old, were randomly assigned to supplement their daily dietwith either an oral quercetin (250 mg/d) or identical placebo(cellulose) capsules for 8 weeks. the supplements were providedto the patients biweekly. anthropometric data as well as glycemicindices, lipid profile and oxidative stress parameters of bloodsamples were determined at the baseline and endpoint of the study.results: dietary quercetin supplementation significantlyimproved the total antioxidant capacity (tac) in the interventiongroup, when compared to the placebo group (p=0.043). italso resulted in a statistically significant reduction in serumconcentration of atherogenic oxidized ldl (ox-ldl) (p < 0.001).however, the 8-week supplementation of this natural flavonolneither altered glycemic parameters (fbs, serum insulin andglycosylated hb (hba1c) level) nor lipid profile and insulinfunction measurement in diabetic patients (p > 0.05).conclusions: oral quercetin supplementation was beneficial inimproving the antioxidant status of patients with type 2 diabeteswhile having no other significant effect on glycemic controland lipid profile; however, conducting further studies, usingdifferent doses, on the glycemiccontrol and/or hyperlipidemiaof thepopulation seems to be valuable.trial registration number: irct2012101911168n