The effect of curcumin and piperine co-supplementation on glycemic indices in prediabetes: A triple-blind randomized controlled trial.

Objective: Patients with prediabetes are at a higher risk of cardiometabolic diseases. There has been growing attention to the role of phytochemicals and nutraceuticals against prediabetes. Previous research supports the efficacy of curcumin in controlling blood glucose level in diabetes but its effect on prediabetes has not been adequately studied. This study aimed to evaluate the effect of curcumin and piperine on prediabetes. Materials and Methods: This triple-blind, randomized controlled trial was performed on patients with prediabetes. The intervention group (n=34) received curcumin + piperine tablets (containing 500 mg curcumin plus 5 mg piperine), while the control group (n=34) used placebo for three months. Before and after three months, fasting blood glucose (FBG), hemoglobin A1c (HbA1c), HOMA-IR, C-reactive protein (CRP), insulin, and anthropometric indices were assessed. The measurements were analyzed using SPSS software. Results: The mean age of participants was 48.4±10.82 years, and 55.8% were females. After the intervention, FBG and HbA1c did not differ significantly between the groups. After 3 months, CRP was significantly reduced in the curcumin + piperine group (p=0.01), while the insulin level increased significantly (p=0.03). After adjustment for CRP and weight at baseline, the difference in changes in insulin, HOMA-IR, and CRP levels between the two groups disappeared. Moreover, there were no changes in anthropometric indices in either group during the study period. Conclusion: Our study revealed that the combination of curcumin and piperine had no significant impact on glycemic indices in patients with prediabetes. Evaluation of the precise effect of this combination on prediabetes requires more clinical trials with varying dosages and durations.