BACKGROUND: The role of selenium (Se) in the management of type 2 diabetes mellitus (T2DM) remains unclear. We systematically assessed the effectiveness and safety of Se supplementation in adults with T2DM. METHODS: MEDLINE, EMBASE and the Cochrane Library were searched up to April 2018 for randomised controlled trials (RCTs) evaluating the effectiveness of Se against a comparator on DM-related outcomes. RESULTS: Four RCTs (241 participants) were included. In individual RCTs, Se supplementation significantly reduced fasting insulin levels [mean difference (MD) = -3.6 μIU mL-1 ; 95% confidence interval (CI) = -6.36 to -0.84; MD = -5.8 μIU mL-1 ; 95% CI = -9.23 to -2.37], homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (MD = -1; 95% CI = -1.79 to -0.21; MD = -1.6; 95% CI, -2.58 to -0.62) and homeostasis model of assessment-estimated B cell function (HOMA-B) (MD = -13.6; 95% CI = -23.4 to -3.8; MD = -22.6; 95% CI = -36.39 to -8.81). No effects of Se were noted on most of the other outcomes of interest. None of the RCTs assessed the mortality, diabetes-related complications, non-high-density lipoprotein (non-HDL), blood pressure and health-related quality of life. The impact on HDL and fasting plasma glucose (FPG) was ambiguous. Only one adverse event (nausea) was reported as a reason for discontinuing the intervention; however, among the studies, the reporting was not accurate. Furthermore, only one RCT reported increase in FPG level in the Se group (MD = 36.38 mg dL-1 ; 95% CI = 15.39-57.37). CONCLUSIONS: Currently, there is no evidence to support the effectiveness of Se supplementation in the T2DM population.
BACKGROUND: The role of selenium (Se) in the management of type 2 diabetes mellitus (T2DM) remains unclear. We systematically assessed the effectiveness and safety of Se supplementation in adults with T2DM. METHODS: MEDLINE, EMBASE and the Cochrane Library were searched up to April 2018 for randomised controlled trials (RCTs) evaluating the effectiveness of Se against a comparator on DM-related outcomes. RESULTS: Four RCTs (241 participants) were included. In individual RCTs, Se supplementation significantly reduced fasting insulin levels [mean difference (MD) = -3.6 μIU mL-1 ; 95% confidence interval (CI) = -6.36 to -0.84; MD = -5.8 μIU mL-1 ; 95% CI = -9.23 to -2.37], homeostasis model of assessment-estimated insulin resistance (HOMA-IR) (MD = -1; 95% CI = -1.79 to -0.21; MD = -1.6; 95% CI, -2.58 to -0.62) and homeostasis model of assessment-estimated B cell function (HOMA-B) (MD = -13.6; 95% CI = -23.4 to -3.8; MD = -22.6; 95% CI = -36.39 to -8.81). No effects of Se were noted on most of the other outcomes of interest. None of the RCTs assessed the mortality, diabetes-related complications, non-high-density lipoprotein (non-HDL), blood pressure and health-related quality of life. The impact on HDL and fasting plasma glucose (FPG) was ambiguous. Only one adverse event (nausea) was reported as a reason for discontinuing the intervention; however, among the studies, the reporting was not accurate. Furthermore, only one RCT reported increase in FPG level in the Se group (MD = 36.38 mg dL-1 ; 95% CI = 15.39-57.37). CONCLUSIONS: Currently, there is no evidence to support the effectiveness of Se supplementation in the T2DM population.