Effect of Chromium Picolinate Supplementation Combined With Resistance Training on Liver Enzymes Levels and Insulin Resistance in Patients With Type 2 Diabetes

* Corresponding Author: Mohammad Parastesh, PhD. Address: Department of Exercise Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. Tel: +98 (933) 1528384 E-mail: m-parastesh@araku.ac.ir 1. Assistant professor, Department of Exercise Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. 2. Associate Professor, Department of Exercise Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. 3. MSc, Department of Exercise Physiology, Faculty of Sport Sciences, Arak University, Arak, Iran. *Mohammad Parastesh1 ,Abbas Saremi2 , Meisam Ebadianejad3


Introduction
here is much evidence to suggest the role of oxidative stress and subsequent production of free radicals in the pathogenesis of diabetes [3]. Eye, nervous system, kidney and liver failures have been identified as ber of insulin receptors which are the symptoms of Type 2 Diabetes (T2D) [9]. Studies have shown that serum concentrations of chromium picolinate in diabetic patients and in those with glucose intolerance are significantly lower than in controls [11].
Physical activity can enhance the skeletal muscle response to insulin by increasing the expression or activity of proteins involved in metabolism and insulin-signal transduction. Physical activity increases the glycogen synthase activity and expression of glucose transporter proteins. In diabetic patients with insulin deficiency, regular physical exercise can facilitate the entry of glucose into muscle cells and consequently, increase insulin sensitivity and cause the absence of insulin [13]. Overall, there is high controversy on the effects of chromium picolinate supplementation, and the beneficial effect of resistance training mechanism combined with chromium picolinate supplementation on liver enzymes is not clear yet.

Materials and Methods
The present study is a quasi-experimental study with pretest/post-test design. Thirty-four middle-aged men with T2D referred to Shiraz Medical Center were voluntarily participated in this study. They were randomly divided into three groups of diabetic control (n=10), resistance training with placebo (n=12) and resistance training with chromium picolinate supplementation (n=12). The subjects' skinfold thickness was measured using a caliper (Seahan, South Korea) and the fat percentage was measured according to Pollock and Jackson (1976)'s method. Blood parameters including liver enzymes were analyzed using Pars Azmoon kits (Pars Azmoon Inc., Tehran, Iran). Fasting blood glucose was measured by a glucose assay kit (Pars Azmoon) with a sensitivity of 5 mg/dL. For serum insulin level measurement, ELISA kit (Monobind Co. US) with a sensitivity of 0.15 Μg/mL was used. To observe the overload principle, intensity of exercise program from 1-4 weeks was 40-50% of one Repetition Maximum (1RM), 2-3 sets each with 15-20 reps; from 6-8 weeks, the intensity was 75%-85% of 1RM intensity, 2-3 sets each with 8-10 reps [18]. Experimental groups received chromium picolinate supplementation at a dose of 400 mg per day for 8 weeks, twice per day after breakfast and dinner.
Statistical analysis was performed in SPSS V. 22 software by using ANCOVA and Bonferroni Post Hoc test at P≤0.05 after testing the assumption of normality by Shapiro-Wilk test and the equality of variances by Levene' test.

Result
ANCOVA results showed no significant difference in fasting blood sugar (F=6.48, P=0.66) between the study groups after intervention, but in terms of serum insulin levels (F=116.97, P=0.001) and insulin resistance index (HOMA-IR) (F=23.26, P=0.001) the difference between groups was significant after intervention. Based on Bonferroni test results, the serum insulin level (P=0.001) and HOMA-IR (P=0.001) in the training group with chromium picolinate Resistance training combined with chromium picolinate supplementation (P=0.04) and resistance training with placebo (P=0.11) resulted in a significant decrease in HOMA-IR compared to the control group. Also, resistance training combined with supplementation (P=0.01) significantly reduced the waist-to-hip ratio (P=0.04) and fat percentage (P=0.01) compared to diabetic controls. Resistance training combined with supplementation (P=0.01) and placebo (P=0.01) resulted in a significant decrease in Alanine Aminotransferase (ALT) and Aspartate Aminotransferase (AST) compared to diabetic controls (Table 1).

Conclusion
It was concluded that resistance training alone can have favorable effects on hepatic markers and improvement of body composition. Supplementation of chromium picolinate can improve hepatic markers in T2D men, while combination of resistance training with chromium picolinate supplementation has a significant effect on both body composition improvement and hepatic markers in men with T2D.
Less studies have been conducted on the effect of resistance training combined with chromium picolinate supplementation on the serum levels of enzymes and liver failures in T2D men. In order to clarify and confirm the effect of chromium picolinate supplementation along with physical activity on liver enzymes, other training methods are suggested in future studies.

Compliance with ethical guidelines
This study was approved by the Research Ethics Committee of Arak University of Medical Sciences (Code: IR.ARAKMU.REC.1397.172).

Funding
This research did not receive any specific grant from funding agencies in the public, commercial, or not for profit sectors.

Authors' contributions
Conceptualization, methodology, software, validation, formal analysis, investigation, resources, data curation, writing-original draft Preparation, writing-review & editing, visualization, supervision, funding acquisition by all authors; Project administration by Mohammad Parastesh.

Conflicts of interest
The authors declared no conflict of interest.