Background Selenium is an essential nutrient with antioxidant, anti-inflammatory, and immuno-regulatory properties. Studies have displayed that in critically ill patients, selenium supplementation may be a potentially promising adjunctive therapy. Objective We aimed to present an overview of the effects of selenium supplementation in adult critically ill patients based on published systematic reviews and meta-analyses (SRMAs) of randomized controlled trials (RCTs). Methods A literature search in three electronic databases, PubMed, Scopus, and Web of Science, was performed to find eligible SRMAs until July 2022. For each outcome, the risk ratios (RRs) or mean differences (MDs) and 95% confidence intervals (CIs) were recalculated using either random or fixed effect models. The methodological quality and quality of evidence of the SRMAs were assessed by applying “A Measurement Tool to Assess Systematic Reviews” (AMSTAR2) and Grading of Recommendations Assessment, Development, and Evaluation(GRADE) tools, respectively. Results We included 17 meta-analyses containing 24 RCTs based on inclusion criteria. Selenium supplementation can reduce the incidence of mortality (RR: 0.83, 95% CI 0.71, 0.98, P = 0.024) and incidence of acute renal failure (RR: 0.67, 95% CI 0.46, 0.98, P: 0.038) significantly; however, the certainty of evidence was low. Moreover, with moderate to very low certainty of evidence, no significant effects were found for risk of infection (RR: 0.92, 95% CI 0.80, 1.05, P: 0.207), pneumonia (RR: 1.11, 95% CI 0.72, 1.72, P: 0.675), as well as the length of ICU (MD: 0.15, 95% CI − 1.75, 2.05, P: 0.876) and hospital stay (MD: − 0.51, 95% CI − 3.74, 2.72, P: 0.757) and days on ventilation (MD: − 0.98, 95% CI − 2.93, 0.98, P: 0.329). Conclusions With low quality of evidence, the use of selenium supplementation could improve the risk of mortality and acute renal failure, but not other outcomes in critically ill patients.

Background: It has been recently reported that lipoprotein-associated phospholipase A2 (Lp-PLA2) may predict the risk of cardiovascular disease. The effect of multi-strain probiotics on Lp-PLA2 in patients with type 2 diabetes is still not clear. This study aimed to determine the effect of multi-strain probiotic supplementation on lipoprotein-associated phospholipase A2, and glycemic status, lipid profile, and body composition in patients with type 2 diabetes. Methods: In this randomized double-blind placebo-controlled clinical trial, 68 participants with type 2 diabetes, in the age group of 50-65 years, were recruited and randomly allocated to take either probiotic (n= 34) or placebo (n= 34) for 12 weeks. The primary outcome was lipoprotein-associated phospholipase A2, and secondary outcomes were glycemic parameters, lipid profile, anthropometric characters, and body composition (fat mass and fat-free mass). Results: There was a significant reduction in serum lipoprotein-associated phospholipase A2, in the probiotic group, it dropped by 6.4 units at the end of the study (p <0.001) compared to the placebo group. Probiotic supplementation also resulted in a significant improvements in the hemoglobin A1c and high-density lipoprotein cholesterol 1.5% (p <0.001) and 6 mg/dl (p 0.005). There were no significant changes in other outcomes. Conclusion: We showed that probiotic supplementation was beneficial for reducing Lp-PLA2 and hemoglobin A1c and improving high-density lipoprotein cholesterol which may suggest an improvement in the prognosis in patients with type 2 diabetes.