Potential Benefits of Selenium Supplementation in Reducing Insulin Resistance in Patients with Cardiometabolic Diseases: A Systematic Review and Meta-Analysis

Abstract

Background: Selenium is a trace element that has been reported to be effective in regulating glucose and lipid metabolism. However, there is conflicting evidence from different clinical trials of selenium supplementation in treating cardiometabolic diseases (CMDs). Objective: This meta-analysis aimed to identify the effects of selenium supplementation on insulin resistance, glucose homeostasis, and lipid profiles in patients with CMDs. Methods: Randomized controlled trials (RCTs) of selenium supplementation for treating CMDs were screened in five electronic databases. Insulin levels, homeostatic model assessment of insulin resistance (HOMA-IR), fasting plasma glucose (FPG), and glycosylated hemoglobin A1C (HbA1c) were defined as the primary outcome markers, and lipid profiles were considered the secondary outcome markers. Results: Ten studies involving 526 participants were included in the meta-analysis. The results suggested that selenium supplementation significantly reduced serum insulin levels (standardized men difference [SMD]: −0.53; 95% confidence interval [CI] [−0.84, −0.21], p = 0.001, I2 = 68%) and HOMA-IR (SMD: −0.50, 95% CI [−0.86, −0.14], p = 0.006, I2 = 75%) and increased high-density lipoprotein cholesterol (HDL-C) levels (SMD: 0.97; 95% CI [0.26, 1.68], p = 0.007, I2 = 92%), but had no significant effect on FPG, total cholesterol (TC), triglycerides (TG), low-density lipoprotein cholesterol (LDL-C), and very low-density lipoprotein cholesterol (VLDL-C). Conclusion: Current evidence supports the beneficial effects of selenium supplementation on reducing insulin levels, HOMA-IR, and increasing HDL-C levels. Selenium supplementation may be an effective strategy for reducing insulin resistance in patients with CMDs. However, more high-quality clinical studies are needed to improve the certainty of our estimates.

Selenium Biomarkers and Their Relationship to Insulin Resistance in Women With Obesity

“…Attention should be drawn to the fact that the dietary evaluation of selenium is considered a marker of limited sensitivity because the concentrations of this mineral vary with the soil, which translates into a great oscillation in the amounts present in foods [10,54]. Associated to this, the scarcity of information about the nutritional composition of selenium in foods produced in the several Brazilian geographic regions leads to the use of foreign tables, which implies in over or underestimation of the amount of this mineral [28].…”

“…It is noteworthy that Brazil nuts are the main food source of this trace element, which is also present in meat, foods of animal origin, vegetables, cereals and fruits [7][8][9]. The literature has demonstrated that this mineral presents antioxidant and anti-in ammatory actions, and also participates of the insulin metabolism, with an impact on the glycemic pro le and other aspects related to insulin action [10][11][12].…”

Selenium Species in Diabetes Mellitus Type 2

“…The recent surveys have focused mainly on the correlations between type 2 diabetes mellitus and selenium intake [ 29 , 34 , 80 – 83 ], its level in plasma or serum blood [ 31 , 37 , 84 – 86 ], and Se metabolic comorbidities [ 87 ], and metabolic syndrome [ 88 ]. The association of selenium status with insulin resistance was also examined [ 6 , 89 , 90 ]. Several types of research observational and analytical studies have been used to estimate selenium safe dose and the risk of T2DM, each with its advantages and limitations [ 91 , 92 ].…”

“…As conflicting results have been reported regarding the association of selenium with diabetes mellitus meta-analysis was applied to develop a more correct estimate of the effects’ magnitude [ 28 , 31 , 90 , 93 , 94 ]. That study design reduces bias and produces more reliable findings [ 95 ].…”

“…The meta-analysis aimed to identify the effects of selenium supplementation on insulin resistance and glucose homeostasis presented the opposite conclusion [ 90 ]. This study included 10 randomized controlled trials conducted in Iran and involving 526 participants with treatment periods between 4 and 24 weeks.…”