The efficacy of nutritional phytochemical compounds in improving cognition

The incidence of cognitive disorders is rising, and medications to address cognitive impairments are limited. Phytochemical compounds have had some success in improving cognitive outcomes in preclinical studies. However, the evidence surrounding the implementation of these compounds routinely in (1) improving cognition in healthy individuals or (2) as prophylaxis and treatment against the cognitive sequelae of neurological insult has not been collated. To address this, the evidence base surrounding the impact of phytochemical agents on cognitive function in healthy individuals was reviewed. Web of Science, PubMed, PsycNET, and AYUSH Research Portal were systematically searched for double-blind and single-blind randomized controlled trials assessing the efficacy of Curcuma longa, Bacopa monnieri, Ocimum tenuiflorum, Camellia sinensis, Centella asiatica, Ganoderma lingzhi, and Rosmarinus officinalis on cognitive function. Seven studies met inclusion. These examined the impact of B. monnieri, O. tenuiflorum, or C. sinensis. There was no benefit of B. monnieri or C. sinensis on processing speed, attention, working memory, language, psychomotor function, or overall cognitive performance. O. tenuiflorum improved reaction times on an executive function task. Further, more methodologically robust trials of longer duration are recommended to investigate the efficacy of phytochemical supplementation for cognition.