Coenzyme Q10 is a naturally occurring substance found in every body cell. It is an essential component of the mitochondria, the energy producing organelles within our cells. CoQ10 is part of the electron transport chain and participates in aerobic cellular respiration leading to the production of ATP, the energy molecule. Organs which have the highest energy requirements such as the heart, liver and kidney have the highest CoQ10 concentrations.
The biosynthesis of coenzyme Q10 involves three major steps. Firstly, the synthesis of the benzoquinone structure from either tyrosine or phenylalanine, two amino acids. Secondly, the synthesis of the isoprene side chain from acetyl-coenzyme A (CoA) via the mevalonate pathway, and thirdly, the joining or condensation of these two structures.
The enzyme hydroxymethylglutaryl (HMG)-CoA reductase plays a critical role in the regulation of coenzyme Q10 synthesis as well as the regulation of cholesterol synthesis.
During gastrointestinal uptake, dietary CoQ10 is efficiently reduced to the antioxidant-active ubiquinol with a low redox potential after its oxidation; the respiratory chain recycles CoQ10 back to its reduced form. CoQ10 is metabolised in all tissues, while a major route for its elimination is biliary and faecal excretion. After withdrawal of CoQ10 supplementation levels return to normal within a few days.
Cooking by frying has shown to reduce the CoQ10 content in food by 14–32%, however no detectable destruction of CoQ10 is found when food is boiled.