Coenzyme Q10 improves blood pressure and glycaemic control:: a controlled trial in subjects with type 2 diabetes

Objective: Our objective was to assess effects of dietary supplementation with coenzyme Q(10) (CoQ) on blood pressure and glycaemic control in subjects with type 2 diabetes, and to consider oxidative stress as a potential mechanism for any effects. Subjects and design: Seventy-four subjects with uncomplicated type 2 diabetes and dyslipidaemia were involved in a randomised double blind placebo-controlled 2x2 factorial intervention. Setting: The study was performed at the University of Western Australia, Department of Medicine at Royal Perth Hospital, Australia. Interventions: Subjects were randomly assigned to receive an oral dose of 100 mg CoQ twice daily (200 mg/day), 200 mg fenofibrate each morning, both or neither for 12 weeks. Main outcome measures: We report an analysis and discussion of the effects of CoQ on blood pressure, on long-term glycaemic control measured by glycated haemoglobin (HbA,c), and on oxidative stress assessed by measurement of plasma F-2-isoprostanes. Results: Fenofibrate did not alter blood pressure, HbA(1c), or plasma F-2-isoprostanes. There was a 3-fold increase in plasma CoQ concentration (3.4 +/- 0.3 mumol/l, P < 0.001) as a result of CoQ supplementation. The main effect of CoQ was to significantly decrease systolic (-6.1 +/- 2.6mmHg, P=0.021) and diastolic (-2.9 +/- 1.4mmHg, P=0.048) blood pressure and HbA(1c) (-0.37 +/- 0.17%, P=0.032). Plasma F-2-isoprostane concentrations were not altered by CoQ (0.14 +/- 0.15nmol/l, P=0.345). Conclusions: These results show that CoQ supplementation may improve blood pressure and long-term glycaemic control in subjects with type 2 diabetes, but these improvements were not associated with reduced oxidative stress, as assessed by F-2-isoprostanes. Sponsorship: This study was supported by a grant from the NHMRC, Australia.