Investigating the effect of combined use of selenium and Myo-inositol supplements on thyroid function and autoimmune characteristics in thyroid disorders: a systematic review and meta-analysis.

BACKGROUND: This study aimed to systematically review the effect of selenium and inositol combination on thyroid function, autoimmune characteristics in thyroid diseases. RESEARCH DESIGN AND METHODS: To identify eligible studies, a systematic search was conducted in the PubMed/MEDLINE, Science-Direct, CINHAL, EMBASE, SCOPUS, Psychinfo, Cochrane, ProQuest, and Web of Science were searched using the main concepts, and all English-written articles that were published between 2007 and 2022 and had an available full text were examined. RESULTS: The data analysis of this research revealed that after the simultaneous use of selenium and inositol supplements, the level of Triiodothyronine(T3) increased by 0.105 in patients with thyroid disorders although this increase was not significant (P-value: 0.228). The level of Thyroxine (T4) significantly increased by 0.06 (P-value: 0.04). Anti-Thyroid Peroxidase Antibody (TPOAb) titer decreased by 119.36%, which was not significant (P-value: 0.070). Finally, the level of Thyroid-stimulating hormone (TSH) decreased by 1.45%, which was a significant change (P-value: 0.001). CONCLUSION: It was observed that simultaneous use of selenium and inositol supplements did not change the T3 and TPOAb titer levels; however, it leads to a decrease in TSH and increase in T4 levels. Further studies are required due to the limited number of studies.

Effects of vitamin D3 supplementation for 12 weeks on serum levels of anabolic hormones, anaerobic power, and aerobic performance in active male subjects: A randomized, double-blind, placebo-controlled trial.

Maintenance of the serum 25-hydroxyvitamin D (25-OH-D) concentration at recommended levels is essential due to its role in the regulation of anabolic hormones and athletic performance. However, the results of the clinical experiments in athletes are controversial. The present study aimed to investigate the effect of vitamin D3 supplement on serum levels of anabolic hormones, cortisol, anaerobic and aerobic performance in active males. In this double-blind, randomized controlled trial, 46 active males randomly assigned to vitamin D3 supplement (VDS; 2000 IU/day) or placebo for 12 weeks. The Wingate test, VO2max, and serum levels of 25-OH-D, Parathyroid hormone (PTH), total testosterone, growth hormone (GH), Insulin-like growth factor-1 (IGF-1), and cortisol were assessed. Subjects in the VDS group had a higher serum level of 25-OH-D (p = 0.004), VO2max (p = 0.016), and average power (p = 0.044) compared to the placebo at the end of the study. Also, lower levels of PTH (p = 0.004) and fatigue index (p < 0.001) were observed in VDS group at the end of the study. The serum cortisol levels were reduced significantly only in subjects with vitamin D deficiency in VDS group (p = 0.042). There was a significant reduction in serum testosterone levels in VDS group (p = 0.013). No change was indicated in serum levels of GH and IGF-1 in VDS group compared to the placebo (p > 0.05). The present study showed an improvement in aerobic capacity, anaerobic performance, and vitamin D status following vitamin D3 supplementation. However, more studies are required for the effect of vitamin D3 on serum concentration of anabolic hormones.

The effect of glutamine supplementation on athletic performance, body composition, and immune function: A systematic review and a meta-analysis of clinical trials.

BACKGROUND & AIM: This systematic review and meta-analysis of available evidence was conducted to obtain a conclusive result on the effects of glutamine supplementation on athletes. METHODS: Systematic review and meta-analysis. Data related to body mass, lean body mass, body fat percentage, Vo2 max, lymphocytes, leukocytes and neutrophil counts were extracted to determine the effects of GLN on performance outcomes. DATA SOURCES: The literature search was conducted across the databases Pubmed, Scopus, ISI Web of Science, SID (Scientific Information Database) and Cochrane Central Register of Controlled Trials, covering a period up to January 2017. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: Clinical trials evaluating glutamine supplementation outcomes on athletes aged over 18 were included. RESULTS: A total of 47 studies were included in the systematic review, and 25 trials matched the inclusion criteria for the meta-analysis. According to the meta-analysis, glutamine has a significant effect on weight reduction (WMD = -1.36 [95% CI: -2.55 to -0.16], p = 0.02). Moreover, neutrophil numbers were reduced following glutamine intake at doses greater than 200 mg/kg body weight (WMD = -605.77 [95% CI: -1200.0 to 52.1]; P = 0.03). Also, supplementation by glutamine dipeptide resulted in higher blood glucose after exercise (WMD = 0.51 [95% CI: 0.18, 0.83] mmol/l; P = 0.002). There was no association between glutamine ingestion and other outcomes investigated. CONCLUSION: According to this meta-analysis, generally, glutamine supplementation has no effect on athletics immune system, aerobic performance, and body composition. However, the current study showed that glutamine resulted in greater weight reduction. In addition, the present study suggests that the efficacy of glutamine supplementation on neutrophil numbers could be affected by supplement type and dose.