The effects of selenium supplementation on blood lipids and blood pressure in adults: A systematic review and dose-response meta-analysis of randomized control trials

Background: Previous studies evaluating the effects of selenium supplementation on lipid profile and blood pressure (BP) offer contradictory findings. This systematic review and meta-analysis assessed the effects of se-lenium supplementation on these lipid profile and BP.Methods: In order to identify interrelated clinical trials, we performed a comprehensive literature search in the online databases, including PubMed, Scopus, Embase, and ISI web of science, up to December 2021.Results: The analysis of the data established that selenium supplementation did not significantly affect TG level (WMD:-0.84 mg/dL; 95 % CI:-4.74, 3.05, p = 0.671), LDL-C (WMD: 0.86 mg/dL; 95 % CI:-1.21, 2.95, p = 0.416), and HDL-C (WMD: 0.3 mg/dL; 95 % CI:-0.66, 1.27, p = 0.535). however, there was a significant reduction in TC levels following selenium supplementation (WMD:-2.11 mg/dL; 95 % CI:-4.09,-0.13, p = 0.037). After subgroup analysis, when the baseline levels of LDL-C were < 130 mg/dL, selenium supplementation elicited a significant increase in LDL-C levels (WMD: 2.89 mg/dL; 95 % CI: 0.26, 5.51, p = 0.031). For BP, se-lenium supplementation significantly increased SBP (WMD: 2.02 mmHg; 95 % CI: 0.50, 3.55, p = 0.009), while it had no significant effect on DBP (WMD: 0.39 mmHg; 95 % CI: (-0.89, 1.68, p = 0.551)).Conclusion: Although our findings suggest selenium may have possible therapeutic effects in improving TC and VLDL, because of its negative effects on LDL and BP, selenium supplementation for cardiovascular protection should be recommended with caution.