Influence of cinnamon on glycemic control in subjects with prediabetes: a randomized controlled trial

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 if cinnamon’s glucose-lowering properties can be leveraged in individuals with prediabetes.

To investigate the effects of cinnamon on measures of glucose homeostasis in prediabetes.

This double-blind, placebo-controlled, clinical trial randomized adult subjects meeting any criteria for prediabetes to receive cinnamon 500 mg or placebo thrice daily (n=27/group). Participants were enrolled and followed at two academic centers for 12 weeks.

Primary outcome was the between-group difference in fasting plasma glucose (FPG) at 12 weeks from baseline. Secondary endpoints included the change in 2-hr PG of the oral glucose tolerance test (OGTT), and the change in the PG area under the curve (AUC) derived from the OGTT.

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<0.05). When compared to the respective baseline, cinnamon, but not placebo, resulted in a significant decrease of the AUC PG (P<0.001) and of the 2-hr PG of the OGTT (P<0.05). There were no serious adverse events in either study group.

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.