Article - Curcumin extract improves beta cell functions in obese patients with type 2 diabetes: a randomized controlled trial.

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Take home message

Curcumin appears to be safe and effective for the management of patients with T2DM and obesity when given with metformin.

Evidence category

A: Meta-analyses, position-stands, randomized-controlled trials (RCTs)

Summary review

Introduction

The aim of this study was to evaluate the potential benefits of curcumin in patients with obesity and type 2 diabetes mellitus (T2DM) on β-cell function as well as metabolic and obesity markers.

Methods

Double-blind, randomised, placebo-controlled trial conducted in Thailand.
229 adults aged 35 years or over with diagnosis of T2DM within the past year and body mass index (BMI) over 23.
All subjects received metformin and education on healthy nutrition and lifestyle.
Patients were randomised to 3 x 2 curcumin capsules per day with a total daily curcuminoid content of 1500mg or matching placebo.
Duration: 12 months.
Primary outcome: β-cell function (homeostasis model assessment, HOMA-β).
Secondary outcomes: fasting plasma glucose (FPG), glycated haemoglobin (HbA1C), body weight, BMI, insulin, insulin resistance (IR, by HOMA-IR), adiponectin and leptin.

Results

At 12 months, significantly better outcomes were seen in the curcumin compared to the placebo group for all metabolic and β-cell-related measures: HOMA-β (values at 12 months: 136.20 vs 105.19, p<0.01), FPG (115.49 mg/ml vs 130.71 mg/dl, p<0.05), HbA1C (6.12% vs 6.47%, p<0.05), insulin (16.05 uU/ml vs 18.54 uU/ml, p<0.01), HOMA-IR (4.86 vs 6.04, p<0.001), adiponectin (14.51 ug/ml vs 10.36 ug/ml, p<0.001) and leptin (9.42 ug/ml vs 20.66 ug/ml, p<0.001).
At 12 months, BMI and body weight had reduced significantly more in the curcumin compared to the placebo group (values at 12 months: from 27.35 to 25.98 vs 26.94 to 27.34 and 69.92 to 66.1 kg vs 69.50 to 69.3 kg, respectively, both p<0.001, baseline values not significantly different).
In the curcumin group, there was a significant correlation between body weight and HbA1c (p=0.01). There were no significant correlations between any other parameters in either group.
In the curcumin group, 12.3% of patients experienced abdominal pain and 7.9% diarrhoea, compared to none in the placebo group. Headaches were experienced by 1.7% in the placebo and 4.4% in the curcumin group. It was not reported whether these differences were statistically significant. There were no significant differences in kidney or liver function tests between groups.

Conclusion

The authors concluded that curcumin appears to improve β-cell function, IR and body weight in patients with T2DM and obesity with only minor adverse effects.

Clinical practice applications

Curcumin can be a valid supplement alongside metformin to improve metabolic parameters and weight in patients diagnosed with T2DM within the past year and obesity.
Curcumin appears to be safe to be used alongside metformin.

Considerations for future research

Clinical trials on curcumin as a first-line treatment, in conjunction with diet and lifestyle advice, in newly diagnosed T2DM patients and/or pre-diabetics would be of value.
Clinical trials evaluating the safety and efficacy of curcumin alongside other anti-diabetic and anti-obesity drugs, such as GLP1 agonists.

Abstract

BACKGROUND

Type 2 diabetes mellitus (T2DM) is a chronic condition characterized by insulin resistance and impaired insulin production, leading to elevated blood glucose levels. Curcumin, a polyphenolic compound from Curcuma longa, has shown potential in improving insulin sensitivity and reducing blood glucose levels, which may help mitigate type 2 diabetes progression.

OBJECTIVE

To assess the efficacy of improving type 2 diabetes (T2DM).

STUDY DESIGN

This randomized, double-blind, placebo-controlled trial included subjects (n = 272) with criteria for type 2 diabetes.

METHODS

All subjects were randomly assigned to receive curcumin (1500 mg/day) or placebo with blind labels for 12 months. To assess the improvement of T2DM after curcumin treatments body weight and body mass index, fasting plasma glucose, glycosylated hemoglobin A β-cell function (homeostasis model assessment [HOMA-β]), insulin resistance (HOMA-IR), insulin, adiponectin, and leptin were monitored at the baseline and at 3-, 6-, 9-, and 12-month visits during the course of intervention.

RESULTS

After 12 months of treatment, the curcumin-treated group showed a significant decrease in fasting blood glucose (115.49 vs.130.71; P < 0.05), HbA (6.12 vs. 6.47; P < 0.05). In addition, the curcumin-treated group showed a better overall function of β-cells, with higher HOMA-β (136.20 vs. 105.19; P < 0.01) The curcumin-treated group showed a lower level of HOMA-IR (4.86 vs. 6.04; P < 0.001) and higher adiponectin (14.51 vs. 10.36; P < 0.001) when compared to the placebo group. The curcumin-treated group also showed a lower level of leptin (9.42 vs. 20.66; P < 0.001). Additionally, body mass index was lowered (25.9 4 vs.29.34), with a P value of 0.001.

CONCLUSIONS

A 12-month curcumin intervention in type 2 diabetes patients shows a significant glucose-lowering effect. Curcumin treatment appeared to improve the overall function of β-cells and reduce both insulin resistance and body weight, with very minor adverse effects. Curcumin intervention in obese patients with type 2 diabetes may be beneficial.

TRIAL REGISTRATION

Thai clinical trials regentrify no.20140303003.