Effects of selenium supplementation on glycaemic control markers in healthy rodents: a systematic review and meta-analysis.

Overexposure to Se is detrimental to glucose metabolism, mainly because of its pro-oxidant effects and the overexpression of selenoproteins. This systematic review evaluated the effects of Se supplementation on glycaemic control in healthy rodents. The methodology followed the PRISMA. We searched the databases for articles published up to May 2022. The risk of bias and the methodological quality were assessed using the SYRCLE and CAMARADES. The results are presented as meta-analytic estimates of the overall standardised mean difference (SMD) and 95 % CI. Of the 2359 records retrieved, thirteen studies were included, of which eleven used sodium selenite and two used zero-valent Se nanoparticles as supplement. Nine studies were included in the meta-analysis. Generally, the risk of bias was high, and 23·1 % of the studies were of high quality. Supplementation with sodium selenite significantly increased fasting blood glucose (SMD = 2·57 (95 % CI (1·07, 4·07)), I2 = 93·5 % (P = 0·001). Subgroup analyses showed effect size was larger for interventions lasting between 21 and 28 d (SMD = 25·74 (95 % CI (2·29, 9·18)), I2 = 96·1 % (P = 0·001)) and for a dose of 864·7 µg/kg/d of sodium selenite (SMD = 10·26 (95 % CI (2·42, 18·11), I2 = 97·1 % (P = 0·010)). However, it did not affect glutathione peroxidase activity (SMD = 0·60 (95 % CI (-0·71, 1·91)), I2 = 83·2 % (P = 0·37)). The current analysis demonstrated the adverse effects of sodium selenite supplementation on glycaemic control in healthy rodents.

Effects of selenium supplementation on glycemic control markers in healthy rodents: A systematic review protocol.

BACKGROUND: In vivo and in vitro studies have shown that Se has an insulin-mimetic action associated with its antioxidant activity. Other studies, in turn, suggest that high Se doses and high selenoprotein expression interfere with insulin signaling. This study aims to evaluate the effects of Se supplementation on glycemic control markers in healthy rodents. METHODS: The protocol was developed according to the Preferred Reporting Items for Systematic Review and Metaanalysis Protocol (PRISMA-P) and was published in the International Prospective Register of Systematic Reviews database (PROSPERO; CRD4202121201142019119181). Experimental, randomized, or non-randomized studies of healthy rodents models will be included. All forms of supplemented Se will be considered, including organic, inorganic, and synthetic compounds, selenium-enriched yeasts, zerovalent Se nanoparticles, and selenized polysaccharides. Fasting blood glucose will be considered the primary outcome. Homeostatic model assessment, plasma and erythrocyte Se concentration, GPX activity, SELENOP concentration, and other Se biomarkers will be considered secondary outcomes. EMBASE, Scopus, Pubmed/Medline, Web of Science, and CINAHL will be searched for articles published with no language restrictions. Two reviewers will independently conduct the search and selection of articles, data extraction, and quality analysis. The risk of bias and methodological quality analyses of the included studies will be performed using the Systematic Review Center for Laboratory Animal Experimentation (SYRCLE) and Collaborative Approach to Meta-Analysis and Review (CAMARADES) tools, respectively. The results will be presented as a narrative synthesis according to the Synthesis Without Meta-analysis (SWiM) Reporting Guideline. Meta-analyses will be conducted where appropriate using random-effects models. DISCUSSION: The review may clarify the interaction between different forms of supplemented Se and glycemic control in rodents models. The results will provide evidence that will help select doses and forms of Se to administer in clinical trials while according to impact on the glycemic control while elucidating mechanisms of Se metabolism.