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In New Zealand, at least 10 brands of coenzyme Q10 (CoQ10) supplement are available over the counter from health food shops, pharmacies, and the Internet. These products claim that supplementation with coenzyme Q10 increases energy, wellbeing, stamina and muscle performance, strengthens the heart, and scavenges free radicals. The evidence for these effects is equivocal and well-controlled studies are needed. It is also necessary to confirm the bioavailability of the available CoQ10 supplements.
Coenzyme Q10 is an essential cofactor in the mitochondrial electron transport chain and also acts as an antioxidant, sparing, the α-tocopheroxyl radical.1 In mammals, CoQ10 is synthesised in all cells--and the diet is also a source, with meat being the biggest contributor.2
It is unlikely that many healthy New Zealand adults are frankly deficient in CoQ10, but CoQ10 deficiency has been associated with various diseases including Alzheimer's disease and Parkinson's disease. It is also possible that diseases producing oxidative stress may result in CoQ10 depletion. HMG-CoA reductase inhibitor (statin) therapy also decreases CoQ10 synthesis3 and causes a potential CoQ10 deficiency, due to inhibition of the common biosynthetic pathway for cholesterol and CoQ10. Thus, CoQ10 is relevant to at least 100,000 New Zealand patients currently on statin therapy.
The available CoQ10 supplements have different formulations, which may affect absorption.4-6 In particular, supplements in which CoQ10 is dispersed in oil generally have higher bioavailability than those formulated as dry powder tablets.4,6
Therefore we have compared the bioavailability of seven different coenzyme Q10 supplement brands, and provide a basis for selecting brand(s) for clinical use.
Ten healthy adult male volunteers were enrolled in a study approved by the Canterbury Ethics Committee. Participants were excluded if they had taken CoQ10, any vitamin supplements, or medications within the previous 4 weeks. The mean age was 24.2 years (range 21-28 years), the mean height was 179.8 cm (range 173-187 cm), and the mean weight was 71.8 kg (range 60-100 kg). The study was completed between November 2003 and January 2004.
Baseline blood samples were obtained after a 10-hour overnight fast, and CoQ10 supplements were administered as a single nominal dose of 150 mg, with supplement brands given in a different randomised order for each participant and a 1-week washout period between trial days. After administration of the supplement, a...