We previously found that curcuminoids decreased blood glucose and improved insulin resistance by reducing serum free fatty acids (FFAs) 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 A1c (HbA1c,%), serum fasting glucose, FFAs, 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), HbA1c (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 FFAs (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.