Effects of curcumin on glycemic control and lipid profile in prediabetes and type 2 diabetes mellitus: A systematic review and meta-analysis

SCOPE: Studies have demonstrated inconsistent effects of curcumin on glycemic outcomes and lipid parameters in patients with prediabetes and type 2 diabetes mellitus (T2DM). This study aimed to assess the effect of curcumin on glycemic control and lipid profile in prediabetes and T2DM. METHODS AND RESULTS: A systematic search of randomized controlled trials (RCTs) was conducted from inception to June 2018 in electronic sources including AMED, ANZCTR, BioMed Central, CENTRAL, CINAHL, ClinicalTrials.gov, Expanded Academic Index, Google Scholar, ISRCTN, LILACS, MEDLINE, NCCIH, Science Direct, Scopus, Web of Science, and WHO ICTRP. Hand search was also performed. Of the total 486 records, four trials (N = 508) and eight trials (N = 646) were eligible for the meta-analysis of individuals with prediabetes and T2DM, respectively. Curcumin significantly reduced glycosylated hemoglobin (HbA1c) in prediabetics (MD: -0.9%, 95% CI: -1.7 to -0.1%, p = 0.03). Furthermore, T2DM subjects gained favorable reduction in both HbA1c (MD: -0.5%, 95% CI: -1.0 to -0.0%, p = 0.04) and fasting plasma glucose (MD: -11.7 mg/dL, 95% CI: -22.1 to -1.3 mg/dL, p = 0.03). Tendency of lipid profile improvement was also observed. CONCLUSION: Our findings may encourage curcumin supplementation based on its meaningful effect on glycemic control and positive trend on lipid outcomes in prediabetes and T2DM.