Randomised controlled clinical trials have shown supplementation with CoQ10 or CoQ10 plus selenium reduces mortality by approximately 50% in patients with cardiovascular disease, or in the normal elderly population, respectively. Similarly, CoQ10 supplementation improves glycaemic control and vascular dysfunction in type II diabetes, improves renal function in patients with chronic kidney disease, and reduces liver inflammation in patients with non-alcoholic fatty liver disease. The beneficial role of supplemental CoQ10 in the above disorders is considered to result from a combination of its roles in cellular energy generation, as an antioxidant and as an anti-inflammatory agent.

The rationale for CoQ10 supplementation in these disorders is based on its key role in cellular metabolism; in addition to its role in cellular energy generation, CoQ10 has antioxidant and anti-inflammatory action

Meta-analyses of clinical studies have demonstrated that supplementation with CoQ10 significantly reduces levels of the inflammatory mediators C-reactive protein (CRP), interleukin-6 (IL-6) and tumour necrosis factor alpha (TNF-α) respectively.

Most of the body’s daily CoQ10 requirement is derived from endogenous synthesis, and this is known to decline substantially with age [7]. This age-related decline in endogenous CoQ10 synthesis may, therefore, be directly linked to longevity via the development of these degenerative disorders.

The role of CoQ10 supplementation in the treatment or prevention of cardiovascular disease has been detailed in previous reviews [9,10].

Two recently published randomised, double-blind, placebo-controlled clinical trials have demonstrated the efficacy of supplementation with CoQ10 (Q-SYMBIO) or CoQ10 plus selenium (KISEL-10) in substantially reducing mortality risk in patients with heart failure, or in the normal elderly population, respectively.

The potential benefit of CoQ10 supplementation in type II diabetes has been shown repeatedly in studies. A number of studies have identified depleted blood CoQ10 levels in patients with type II diabetes.

Over a dozen controlled clinical trials supplementing CoQ10 (typically 100–200 mg/day for 3–6 months) in type II diabetic patients

CoQ10 supplementation significantly improved fasting plasma glucose and HbA1c (glycated haemoglobin )levels.

Similarly, glycaemic control and blood antioxidant levels were significantly improved in type II diabetics following supplementation (100 mg/day for three months) with the reduced (ubiquinol) form of CoQ10 [29

Supplemental CoQ10 may benefit type II diabetes via several mechanisms, for example by promoting enhanced levels of cellular energy required for glucose metabolism, or via direct modulation of the expression of genes relevant to glucose metabolism, or via its antioxidant action [35].

The use of statins (particularly simvastatin) has been associated with an increased risk of between 10% and 40% of developing type II diabetes [40,41]; this is thought to result from statin-induced depletions of circulatory levels of CoQ10, adiponectin and glucose transporter-4 (GLUT4) protein [42]. Although CoQ10 administration has been shown to prevent simvastatin-induced GLUT4 protein levels in cell culture [43],