Background: Diabetes mellitus is a common metabolic disorders in human and affect a lot of people around the world. Curcumin is a component of turmeric and in many studies therapeutic effects such as anti-hypertensive, anti-hyperlipidemia, anti-hyperglycemia for this substance are shown. Aim: The aim of this study was to investigate the effect of curcumin supplementation on anthropometric indices glycemic control and oxidative stress in overweight patients with type 2 diabetes. Materials and methods: In this randomized, double-blind, placebo-controlled trial, 53 participants with type 2 diabetes were divided randomly into the experimental and control groups to receive either 1500 mg curcumin or placebo capsule three times in a day for 10 weeks. Result: Supplementation with curcumin in type 2 diabetes compare to placebo causes a significant changes in mean weight (− 0.64 ± 0.22 vs. 0.19 ± 0.37 p < 0.05), body mass index (BMI) (0.3 ± 0.03 vs. 0.1 ± 0 p < 0.05), waist circumference (WC) (− 1.2 ± 0.4 vs. − 0.43 ± 0.11 p < 0.05) and fasting blood sugar (FBS) (− 7 ± 2 vs. 3 ± 0.2 p < 0.05) but did not show any difference for hemoglobin A1c (HbA1c), insulin, malondialdehyde (MDA), total antioxidant capacity (TAC), Homeostatic Model Assessment for Insulin Resistance (HOMA-IR) and pancreatic B cell function (HOMA-B) at end of study. Conclusion: This study indicated that daily administration of 1500 mg curcumin has positive effects in reducing fasting blood glucose and weight in patients with type 2 diabetes. Trial registration NCT02529982. Registered 19 August 2015, http://www.clinicaltrial.gov

This study was conducted to elucidate the effects of decaffeinated green coffee bean extract (GCE) on anthropometric indices, glycaemic control, blood pressure, lipid profile, insulin resistance and appetite in patients with the metabolic syndrome (Mets). Subjects were randomly allocated to consume 400 mg GCE or placebo capsules twice per d for 8 weeks. Both groups were advised to follow an energy balanced diet. After GCE supplementation, systolic blood pressure (SBP) significantly reduced compared with the placebo group (−13·76 (sd 8·48) v. −6·56 (sd 9·58) mmHg, P=0·01). Also, GCE treatment significantly reduced fasting blood glucose (FBS) (−5·15 (sd 60·22) v. 29·42 (sd 40·01) mg/dl (−0·28 (SD 3·34) v. 1·63 (SD 2·22) mmol/l); P=0·03) and homoeostatic model of assessment of insulin resistance in comparison to placebo (−1·41 (sd 3·33) v. 1·23 (sd 3·84), P=0·02). In addition, waist circumference (−2·40 (sd 2·54) v. −0·66 (sd 1·17) cm, P=0·009) and appetite score (−1·44 (sd 1·72) v. −0·2 (sd 1·32), P=0·01) of the individuals supplemented with GCE indicated a significant decline. Besides, weight and BMI reduction in the intervention group was almost twice as much as the placebo group; however, this discrepancy was marginally significant (weight: −2·08 (sd 2·11) v. −0·92 (sd 1·30) kg, P=0·05). No difference was observed in terms of glycated Hb (HbA1c) percentage and lipid profile parameters between the two groups. To sum up, GCE administration had an ameliorating effect on some of the Mets components such as high SBP, high FBS and Mets main aetiological factors including insulin resistance and abdominal obesity. Furthermore, GCE supplementation could reduce appetite level.

The aim of this study was to investigate the association between total polyphenol intake, its subclasses (including flavonoids, phenolic acids, stilbenes and lignans), and the metabolic syndrome (MetS). This population-based cross-sectional study was conducted on a representative of 2618 adults, aged 19 to 84 years. Dietary intake was assessed using a validated food-frequency questionnaire and intakes of total polyphenol and four main subclasses of polyphenol including flavonoids, phenolic acids, stilbenes and lignans were determined. Higher consumption of flavonoid intakes was associated with lower odds of enlarged waist circumference, hypertriglyceridemia, low HDL cholesterol, hyperglycemia, hypertension and MetS. Subjects in the highest quartile of lignan intakes had higher odds of having hypertriglyceridemia and hyperglycemia. Subjects in the highest quartile of stilbene intakes had higher odds of having hypertension. Intakes of selected subclasses of polyphenol such as flavonoids are associated with a lower prevalence of MetS among Tehranians.