RATIONALE: Several randomized controlled studies have addressed the effects of cinnamon on changes in glycated hemoglobin (HbA1c) and fasting plasma glucose (FPG) in adult patients with T2D. Almost all studies showed a significant 10-20% decrease in FPG from baseline and improvements in HbA1c, although the latter change often did not achieve statistical significance. These findings in patients with T2D provide the rational to test whether cinnamon exerts similar beneficial effects in patients with prediabetes.