Evaluation of the effect of curcumin and zinc co-supplementation on glycemic measurements, lipid profiles, and inflammatory and antioxidant biomarkers in overweight or obese prediabetic patients: a study protocol for a randomized double-blind placebo-controlled phase 2 clinical trial

BACKGROUND: The prevalence of prediabetes is increasing worldwide. Unfortunately, prediabetes is related to non-communicable diseases. A high risk of developing type 2 diabetes mellitus (T2DM) is reported in people with prediabetes. Curcumin, a polyphenol, might lead to its therapeutic role in obesity and some obesity-related metabolic diseases. Zinc is a trace element that plays a key role in the synthesis and action of insulin, carbohydrate metabolism, and decreasing inflammation. There has been no clinical trial of zinc and curcumin co-supplementation in patients with prediabetes. In previous studies, the single administration of zinc or curcumin has not been conducted on many of the studied markers in prediabetic patients. METHODS: The purpose of this randomized double-blind placebo-controlled clinical trial is to investigate the effect of curcumin and zinc co-supplementation on glycemic measurements, lipid profiles, and inflammatory and antioxidant biomarkers among 84 prediabetic patients with body mass index (BMI) between 25 and 35. Also, liver enzyme, serum zinc, urine zinc, blood pressure, anthropometric parameters, quality of life, adherence to co-supplementation, the side effects of co-supplementation, physical activity, and dietary intake will be assessed. Women or men (18–50 years old for men and 18 years to before menopause for women) will be followed for 3 months (90 days). This study will be conducted at Yazd Diabetes Research Clinic, Shahid Sadoughi University of Medical Sciences. DISCUSSION: A diet rich in antioxidants, polyphenols, and phytochemicals has been shown to have a beneficial role in prediabetes. According to the beneficial properties of curcumin or zinc and inadequate evidence, RCTs are needed to assess the effect of curcumin and zinc co-supplementation in native prediabetes patients. We hope the results of the present trial, negative or positive, fill this gap in the literature and facilitate the approach for a much larger, multi-center clinical trial. In conclusion, a synergic effect of co-supplementation along with a weight-loss diet may delay the progression to type 2 diabetes mellitus. TRIAL REGISTRATION: Iranian Registry of Clinical Trials (IRCT) IRCT20190902044671N1. Registered on 11 October 2019