Cocoa Flavanols Intake and Cognitive Functions:a Systematic Review and Meta-analysis of Randomised Controlled Trials

摘要

Objective The influence of cocoa flavanols(CFs)on cognitive functions in human has been investigated in some clinical trials,but the results are inconclusive.We conduct this systematic review and meta-analysis of randomized controlled trials(RCTs)to figure out whether CFs intervention have a positive effect on cognitive functions.Methods A comprehensive literature search of articles published until June 2019 was performed in PubMed,Cochrane Library,Medline,and Web of Science.Weighted mean difference(WMD)and 95%confidence interval(95%CI)were calculated to reflect the size of the combined effect.Random effect models were used for all analyses.Results A total of 9 RCT studies were finally enrolled in this meta-analysis.CFs has no notable effect on Trail Making Test-A(TMT-A)(WMD:-5.75s,95%CI:-16.71-5.21),which reflects the shifting subdomain of executive function and global executive function.CFs has no significant effect on Trail Making Test-B(TMT-B)(WMD:-11.32s,95%CI:-26.14-3.50),which reflects another specific aspect of the shifting subdomain.Gross cognitive changed as measured by mini mental state examination(MMSE)which consists of a series of items covering cognitive functions except for the executive function domain,but significantly associated with composite z score of several subdomains tests of executive function(WSD:0.40s,95%CI:0.29-0.46).Conclusion This study suggests CFs may have a positive effect on cognitive function,especially executive function.However,large scale and high quality RCTs are needed to further confirm/refute this conclusion.