A Systematic Review And Meta-Analysis On The Effect Of Curcumin (Turmeric) On Fasting Blood Glucose And Glycated Haemoglobin In Patients With Type 2 Diabetes Mellitus

BackgroundHyperglycemia is a recurring metabolic condition known as diabetes mellitus. When glycated haemoglobin (HbA1c) >6.5% and fasting blood glucose (FBG) continuously falls below 126 mg/dl, it is clinically diagnosed. Type 2 diabetes (T2DM) and the emergence of diabetic complications are mostly mediated by oxidative stress and chronic inflammation. Research on the use of natural anti-inflammatory and antioxidant substances, such as curcumin (turmeric), as an adjuvant treatment in the management of T2DM is becoming more and more popular. However, the effects of curcumin on glycemic control in T2DM patients have varied according to the outcomes of randomised control trials. Therefore, this systematic review/meta-analysis was aimed at synthesizing findings from different RCTs to determine the effect of curcumin on fasting blood glucose and glycated haemoglobin in patients with T2DM. MethodSearches were conducted in electronic databases and other sources such as PubMed, CINAHL, CENTRAL, ProQuest, Web of Science, Health Technology Assessment (HTA), Scopus, LILACS, clinicaltrials.gov and google scholar. Key search terms use included curcumin, fasting blood glucose, glycated haemoglobin, and type 2 diabetes mellitus. Relevant RCTs conducted within the last 12 years (2009-2022) were selected and assessed against the inclusion criteria. A summary of the search strategy was presented on a PRISMA flow chart. Data were extracted using standardised data extraction forms and meta-analysis was performed using the RevMan version 5.3. and results presented using forest plots. ResultsFive RCTs with a total of 349 participants were included in the meta-analysis. Curcumin supplementation significantly reduced fasting blood glucose and glycated haemoglobin in patients with type 2 diabetes mellitus when compared with the usual drugs. FBG (MD: -1.84, 95% CI: -4.92 to 1.24, P=0.24, I2=15%). HbA1c (MD: -0.24, 95% CI: -0.55 to 0.07, P=0.13, I2=0%). ConclusionCurcumin supplementation is effective in the management of T2DM and diabetic complication. Further research on ways to bypass the challenges of bioavailability such as the use of nano-micelles may produce greater therapeutic effects on diabetes management.