Oral supplementation of turmeric attenuates proteinuria, transforming growth factor-β and interleukin-8 levels in patients with overt type 2 diabetic nephropathy: A randomized, double-blind and placebo-controlled study

Abstract

Objective. End-stage renal disease (ESRD) due to type 2 diabetic nephropathy is a very common condition which is increasing in prevalence, and is associated with high global levels of mortality and morbidity. Both proteinuria and transforming growth factor-β (TGF-β) may contribute to the development of ESRD in patients with diabetic nephropathy. Experimental studies indicate that turmeric improves diabetic nephropathy by suppressing TGF-β. Therefore, this study investigated the effects of turmeric on serum and urinary TGF-β, interleukin-8 (IL-8) and tumour necrosis factor-α (TNF-α), as well as proteinuria, in patients with overt type 2 diabetic nephropathy. Material and methods. A randomized, double-blind and placebo-controlled study was carried out in the Diabetes Clinic of the Outpatient Department of Shiraz University of Medical Sciences on 40 patients with overt type 2 diabetic nephropathy, randomized into a trial group (n = 20) and a control group (n = 20). Each patient in the trial group received one capsule with each meal containing 500 mg turmeric, of which 22.1 mg was the active ingredient curcumin (three capsules daily) for 2 months. The control group received three capsules identical in colour and size containing starch for the same 2 months. Results. Serum levels of TGF-β and IL-8 and urinary protein excretion and IL-8 decreased significantly comparing the pre- and post-turmeric supplementation values. No adverse effects related to turmeric supplementation were observed during the trial. Conclusion. Short-term turmeric supplementation can attenuate proteinuria, TGF-β and IL-8 in patients with overt type 2 diabetic nephropathy and can be administered as a safe adjuvant therapy for these patients.

Key Words::

• diabetic nephropathy
• IL-8
• proteinuria
• TGF-β
• turmeric

Acknowledgement

This study was funded by the Shiraz Nephro-Urology Research Center of Shiraz University of Medical Sciences, Shiraz, Iran.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.