Curcuminoids exert glucose‐lowering effect in type 2 diabetes by decreasing serum free fatty acids: a double‐blind, placebo‐controlled trial

Scope We previously found that curcuminoids decreased blood glucose and improved insulin resistance by reducing serum free fatty acids ( FFA s) and increasing fatty acid oxidation in skeletal muscle of diabetic rats. This study was to investigate whether curcuminoids have beneficial effects on type 2 diabetic patients, and its possible mechanisms. Methods and results Overweight/obese type 2 diabetic patients ( BMI ≥ 24.0; fasting blood glucose ≥ 7.0 mmol/L or postprandial blood glucose ≥11.1 mmol/L) were randomly assigned to curcuminoids (300 mg/day) or placebo for 3 months. Bodyweight, glycosylated hemoglobin A 1c ( H b A 1c , % ), serum fasting glucose, FFA s, lipids, and lipoprotein lipase ( LPL ) were determined. A total of 100 patients (curcuminoids, n = 50; placebo, n = 50) completed the trial. Curcuminoids supplementation significantly decreased fasting blood glucose ( p < 0.01), H b A 1c ( p = 0.031), and insulin resistance index ( HOMA ‐ IR ) ( p < 0.01) in type 2 diabetic patients. Curcuminoids also led to a significant decrease in serum total FFA s ( p < 0.01), triglycerides ( P = 0.018), an increase in LPL activity ( p < 0.01). Conclusion These findings suggest a glucose‐lowering effect of curcuminoids in type 2 diabetes, which is partially due to decrease in serum FFAs, which may result from promoting fatty acid oxidation and utilization.