Role of Vitamin D on glycemic control and oxidative stress in type 2 diabetes mellitus

Abstract

Background:Vitamin D deficiency may play a key role in the development of impaired glucose tolerance, type 2 diabetes mellitus (T2DM), and metabolic syndrome. Several studies have shown that Vitamin D has an antioxidant property. We aimed to investigate 25-hydroxy Vitamin D (25[OH]D) levels in patients with T2DM and in nondiabetic healthy controls and to ascertain the impact of 25(OH)D levels on glycemic control and oxidative stress in T2DM patients.Materials and Methods:Thirty male patients with T2DM and twenty age- and socioeconomic status-matched male healthy controls were included in the study. Fasting and postprandial blood sugar and glycated hemoglobin (HbA1c) were measured. Enzyme activity of superoxide dismutase (SOD) and glutathione peroxidase (GPx) was determined by spectrophotometric assay, and serum levels of 25(OH)D were measured using radioimmunoassay.Results:Serum Vitamin D levels were significantly lower in patients with T2DM than healthy controls (P = 0.015). There was a significantly lower GPx activity in patients with T2DM than controls (P = 0.048), but the difference in SOD activity did not reach statistical significance. There was a significant negative correlation between serum Vitamin D levels and HbA1c (P = 0.016), but no statistical correlation was shown between serum Vitamin D levels and GPx and SOD.Conclusion:We conclude that low level of Vitamin D might play a significant role in T2DM pathogenesis. Hence, Vitamin D supplementation may improve glycemic control and oxidative stress in T2DM.

Vitamin D supplementation does not improve plasma thiol/disulfide homeostasis

“…Studies on the effect of vitamin D supplements on oxidative stress have reported conflicting results. For example, in contrast to George et al, who found an increase in hepatic glutathione peroxidase gene expression in streptozotocininduced diabetic rats, 20 Bhat et al reported reduced activity of GSH-dependent enzymes, glutathione peroxidase, and glutathione reductase in rats with depleted vitamin D. 21 Similarly, despite the availability of research suggesting that vitamin D supplementation in human beings reduces oxidative stress in conditions such as type 2 diabetes, 16,22 polycystic ovary syndrome, 23 and non-alcoholic fatty liver disease, 24 as well as in asymptomatic individuals, 25 other studies have shown that oxidative stress was not improved in type 2 diabetes 26 or in gestational diabetes. 27 The current study also found that vitamin D supplementation did not reduce oxidative stress.…”

“…In another study evaluating healthy adults, the total oxidant status and ischemia-modified albumin, a marker of protein oxidation, were increased while the total antioxidant status was decreased in the vitamin D deficiency group. 14 Vitamin D deficiency has also been associated with increased oxidative stress in type 2 diabetic rats, 15,16 nutritional rickets, 17 multiple sclerosis, 18 and in healthy children. 19 All these data are consistent with the present results.…”

The Effects of Vitamin D Supplementation on Biomarkers of Inflammation and Oxidative Stress in Diabetic Patients: A Systematic Review and Meta-Analysis of Randomized Controlled Trials

“…However, in another meta-analysis study conducted in the obese and overweight people, supplementation with vitamin D did not have a significant impact on changes in selected inflammatory biomarkers levels [14]. Recently, a number of clinical trials evaluating vitamin D administration on different populations have been performed to determine if circulating levels of inflammatory markers and biomarkers of oxidative stress are affected among diabetic patients [15][16][17][18]. However, the sample size of these trials was small, the quality of the studies was variable, and the results were inconsistent.…”

The Impact of Different Regimens of Vitamin D3 on Glucose Homeostasis in Type 2 Diabetic Patients

“…Previous observational studies showed that 25(OH)D3 levels were lower in patients with T2DM than in non-diabetic patients, and there was an inverse association between 25(OH)D3 levels and glycemic control parameters and inflammatory mediator [4][5][6][7]26]. However, the findings of interventional studies regarding the effect of Vitamin D3 administration on the control of T2DM are controversial [17].…”

“…Recently, particular attention has been focused on the relationship between Vitamin D deficiency and a wide array of diseases, including T2DM [4][5][6][7][8]. In addition to the Vitamin D effects on calcium (Ca) homeostasis and bone health, Vitamin D also mediates non-calcemic actions in different tissues through Vitamin D receptors (VDRs) [9,10].…”