Influence of Cinnamon on Glycemic Control in Individuals With Prediabetes: A Randomized Controlled Trial

CONTEXT: The identification of adjunct safe, durable, and cost-effective approaches to reduce the progression from prediabetes to type 2 diabetes (T2D) is a clinically relevant, unmet goal. It is unknown whether cinnamon’s glucose-lowering properties can be leveraged in individuals with prediabetes. OBJECTIVE: The objective of this work is to investigate the effects of cinnamon on measures of glucose homeostasis in prediabetes. DESIGN, SETTING, PARTICIPANTS, AND INTERVENTION: This double-blind, placebo-controlled, clinical trial randomly assigned adult individuals meeting any criteria for prediabetes to receive cinnamon 500 mg or placebo thrice daily (n = 27/group). Participants were enrolled and followed at 2 academic centers for 12 weeks. MAIN OUTCOME MEASURES: Primary outcome was the between-group difference in fasting plasma glucose (FPG) at 12 weeks from baseline. Secondary end points included the change in 2-hour PG of the oral glucose tolerance test (OGTT), and the change in the PG area under the curve (AUC) derived from the OGTT. RESULTS: From a similar baseline, FPG rose after 12 weeks with placebo but remained stable with cinnamon, leading to a mean between-group difference of 5 mg/dL (P < .05). When compared to the respective baseline, cinnamon, but not placebo, resulted in a significant decrease of the AUC PG (P < .001) and of the 2-hour PG of the OGTT (P < .05). There were no serious adverse events in either study group. CONCLUSIONS: In individuals with prediabetes, 12 weeks of cinnamon supplementation improved FPG and glucose tolerance, with a favorable safety profile. Longer and larger studies should address cinnamon’s effects on the rate of progression from prediabetes to T2D.