Coenzyme Q10 and Cognition: A Review.

Background and Objective: With an increase in the number of older citizens in most Western countries, cognitive decline is becoming an increasingly significant issue. Numerous age-related metabolic and physiological changes, such as increased inflammation and oxidative stress, decreased adenosine triphosphate (ATP) production, poorer cardiovascular function, and reduced cerebral blood flow, have been implicated in cognitive decline, prompting research into interventions. Among these, Coenzyme Q10 (CoQ10), an antioxidant and metabolic stimulant, has shown promise in improving some of the underlying biological mechanisms of cognitive decline. However, not much is known about the efficacy of CoQ10 supplementation on cognition in the elderly. Therefore, the aim of this review is to explore the efficacy of CoQ10 supplementation on cognitive function. Methods: We conducted a review of animal studies and human clinical trials investigating the effect of CoQ10 supplementation on cognition in samples who were healthy or with specific diseases. Overall, twelve studies demonstrated improved cognitive function and two showed a reduction in oxidative stress in response to CoQ10 supplementation, either alone or in combination with other compounds. Out of eight human clinical trials in healthy subjects (n = 2) and disease states (n = 6), four showed evidence of a beneficial effect of CoQ10 supplementation on cognition, while two demonstrated an increase in cerebral blood flow. Disparity in the results of the clinical trials presented here is likely due to differing testing procedures, inconsistent use of cognitive assessments, and/or varying bioavailability of different preparations of CoQ10. Conclusions: There is some evidence to suggest that cognition and the biological mechanisms that regulate it are positively impacted by CoQ10 therapy. However, it is crucial to note that the literature presents mixed results, with many human clinical trials also reporting no benefit of CoQ10 supplementation on cognitive performance. To fully evaluate the benefits of CoQ10 on cognitive function in ageing and in neurodegenerative diseases, future studies are needed that target possible mechanisms and utilise a wider range of cognitive assessments.