In a recent systematic review and meta-analysis report (Nutrients 2016, 8, 57), we critically appraised and summarized current evidence to determine the effects of chicken essence in improving cognitive functions as well as its safety. [...].
Chicken essence (CE) is a popular traditional remedy in Asia, which is believed to improve cognitive functions. CE company claimed that the health benefits were proven with research studies. A systematic review was conducted to determine the cognitive-enhancing effects of CE. We systematically searched a number of databases for randomized controlled trials with human subjects consuming CE and cognitive tests involved. Cochrane's Risk of Bias (ROB) tool was used to assess the quality of trials and meta-analysis was performed. Seven trials were included, where six healthy subjects and one subject with poorer cognitive functions were recruited. One trial had unclear ROB while the rest had high ROB. For executive function tests, there was a significant difference favoring CE (pooled standardized mean difference (SMD) of -0.55 (-1.04, -0.06)) and another with no significant difference (pooled SMD of 0.70 (-0.001, 1.40)). For short-term memory tests, no significant difference was found (pooled SMD of 0.63 (-0.16, 1.42)). Currently, there is a lack of convincing evidence to show a cognitive enhancing effect of CE.