Effect of Chronic Dark Chocolate or Cocoa Intake on Cognitive Function: A Grading of Recommendations Assessment, Development, and Evaluation (GRADE)–Assessed Systematic Review and Meta-Analysis of Randomized Controlled Trials

Context Cocoa and dark chocolate are abundant dietary sources of polyphenols and may improve cognitive performance. Previous studies have been controversial. Objective In this systematic review and meta-analysis of randomized controlled trials we aimed to review the effect of regular dark chocolate or cocoa intake on cognitive function. Data sources The literature search included the Web of Science, PubMed, and Scopus databases up to January 2025. Data extraction A random-effects model was used to calculate the weighted mean difference (WMD) and 95% CI. The Cochrane Collaboration criteria tool was used to evaluate the risk of bias for the included studies. The quality of evidence was assessed using the Grading of Recommendations Assessment, Development, and Evaluation (GRADE) system. Data analysis Eight studies of the 16 included studies of 2847 participants found a significant effect on at least 1 of the cognitive function domains. Chronic dark chocolate or cocoa intake significantly improved results of the Trail Making Test (TMT) part A (WMD, −4.51; 95% CI, −8.41 to −0.60; P = .024) and part B (WMD, −13.1; 95% CI, −17.73 to −8.47; P < .001) and verbal fluency test (VFT) (WMD, 3.15; 95% CI, 0.71-5.6; P = .012). Subgroup analysis showed that this efficacy is greater in dosages of ≥500 mg cocoa flavanol/d and duration ≥8 weeks. The results of studies on working and verbal memory were inconsistent. Participant scores on the Mini-Mental State Examination (MMSE) did not indicate any beneficial effects of chronic dark chocolate or cocoa intake. The quality of evidence was moderate and high. Conclusions Our findings suggest that chronic dark chocolate or cocoa intake has potential benefits on some dimensions of cognitive function, including executive function, attention, processing speed, language, and rote memory. Systematic Review Registration PROSPERO registration No. CRD42024568294