The Effect of Flavanol-Rich Cocoa on Insulin Sensitivity in Overweight and Obese Individuals: A Meta-Analysis

Objective. This review aims to assess the effects of flavanol-rich cocoa for insulin sensitivity in overweight and obese individuals. Methodology. A structured search strategy using the MeSH, PubMed and Cochrane Library databases was done. A fixed effects meta-analysis of randomized controlled trials assessing the effects of flavanol-rich cocoa products on insulin sensitivity/resistance studies meeting the inclusion criteria was conducted. The primary outcome measures were the Quantitative Insulin Sensitivity Check Index (QUICKI) and the Homeostasis Model of Assessment (HOMA) between treatment and control groups. Results. Three randomized controlled trials consisting of 118 and 101 individuals were included in the QUICKI and HOMA arm analyses, respectively. The populations studied were either overweight or obese adults. Treatment duration was a minimum of 2 weeks. The mean QUICKI and HOMA in the treatment arms across all trials were: -0.00 [95% confidence interval (CI), -0.01, -0.00], p = 0.39; and -0.36 (95% CI, -0.56, -0.15), p = 0.0006 respectively. Conclusion. The meta-analysis suggests that flavanol-rich cocoa is superior to flavanol-poor cocoa in increasing insulin sensitivity among overweight and obese individuals. There was significant statistical heterogeneity across studies. Further investigations on the preparation, appropriate amount and treatment duration are warranted before cocoa products can be recommended for this purpose.