The scientific literature about probiotic intake and its effect on sports performance is growing. Therefore, the main aim of this systematic review, meta-analysis and meta-regression was to review all information about the effects of probiotic supplementation on performance tests with predominance of aerobic metabolism in trained populations (athletes and/or Division I players and/or trained population: ≥8 h/week and/or ≥5 workouts/week). A structured search was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA^®) statement and PICOS guidelines in PubMed/MEDLINE, Web of Science (WOS), and Scopus international databases from inception to 1 November 2021. Studies involving probiotic supplementation in trained population and execution of performance test with aerobic metabolism predominance (test lasted more than 5 min) were considered for inclusion. Fifteen articles were included in the final systematic review (in total, 388 participants were included). After 3 studies were removed due to a lack of data for the meta-analysis and meta-regression, 12 studies with 232 participants were involved. With the objective of assessing the risk of bias of included studies, Cochrane Collaboration Guidelines and the Physiotherapy Evidence Database (PEDro) scale were performed. For all included studies the following data was extracted: authors, year of publication, study design, the size of the sample, probiotic administration (dose and time), and characteristics of participants. The random effects model and pooled standardized mean differences (SMDs) were used according to Hedges’ g for the meta-analysis. In order to determine if dose and duration covariates could predict probiotic effects, a meta-regression was also conducted. Results showed a small positive and significant effect on the performance test with aerobic metabolic predominance (SMD = 0.29; CI = 0.08–0.50; p < 0.05). Moreover, the subgroup analysis displayed significant greater benefits when the dose was ≥30 × 10⁹ colony forming units (CFU) (SMD, 0.47; CI, 0.05 to 0.89; p < 0.05), when supplementation duration was ≤4 weeks (SMD, 0.44; CI, 0.05 to 0.84; p < 0.05), when single strain probiotics were used (SMD, 0.33; CI, 0.06 to 0.60; p < 0.05), when participants were males (SMD, 0.30; CI, 0.04 to 0.56; p < 0.05), and when the test was performed to exhaustion (SMD, 0.45; CI, 0.05 to 0.48; p < 0.05). However, with references to the findings of the meta-regression, selected covariates did not predict probiotic effects in highly trained population. In summary, the current systematic review and meta-analysis supported the potential effects of probiotics supplementation to improve performance in a test in which aerobic metabolism is predominant in trained population. However, more research is needed to fully understand the mechanisms of action of this supplement.

Over the last two decades, a plethora of disease models and human studies have confirmed the beneficial effects of molecular hydrogen (H₂), a simple biotherapeutic gas. Recent small-scale studies evaluating the effects of hydrogen-rich water (HRW) on various metabolic conditions pointed to advantageous effects of HRW in regulating blood lipid profiles. However, to the best of the authors’ knowledge, no systematic review and/or meta-analysis (SRMA) were published considering HRW consumption and lipid/lipoprotein status. Therefore, the aim of this SRMA was to assess the effects of HRW consumption on blood lipid panel in clinical populations. The search strategy was designed using PRISMA guidelines, and the databases PubMed/Medline, Web of Science, and Scopus were explored from inception until 4 October 2022. A total of seven studies satisfied all the eligibility criteria and were included in SRMA. The results for the pooled meta-analysis showed a significant reduction in total cholesterol, low-density lipoprotein, and triglycerides after HRW intake (p = 0.01), with small to moderate effects (pooled SMD = −0.23 (from −0.40 to 0.05); pooled SMD = −0.22 (from −0.39 to 0.04); pooled SMD = −0.38 (from −0.59 to 0.18), respectively). Our findings indicate that drinking HRW can significantly improve lipid status in the clinical populations. Additional studies are warranted to further validate this connection.

Background: In recent years, interest in probiotic supplementation has increased among athletes due to its potential benefits on sports performance. Thus, the aim of this trial was to investigate Lactobacillus plantarum’s effects on sports performance, intestinal damage, and oxidative stress biomarkers. Methods: Twenty-two physically active participants, nine females and thirteen males (age: 32.8 ± 5.2 years; height: 1.73 ± 0.1 m (meters); body mass: 72.2 ± 10.3 kg (kilograms) volunteered in this randomized, double-blind, placebo-controlled, parallel study. The participants performed a strenuous exercise session, and immediately after, their perceived exertion was assessed and blood samples were drawn to assess intestinal damage (IFABP: intestinal fatty acid binding protein) and oxidative stress (PC: protein carbonyls; TAC: total antioxidant capacity; total proteins; GSSG: glutathione disulfide; GSH: reduced glutathione and catalase). Twenty-four hours later, the participants ranked their recovery status and completed various sports performance tests: CMJ (countermovement jump), RAST (running-based anaerobic sprint), and YOYO IR1 (YOYO intermittent recovery test level 1). This was followed by a four-week supplementation period, in which the participants ingested one probiotic capsule per day containing 10 billion CFU (colony forming units) of Lactobacillus plantarum or a placebo capsule (dextrose). Results: The paired samples t-test revealed a significantly better result in the YOYO IR1 test in the probiotic group, while a significant reduction was observed in the TAC levels in the placebo group. Conclusions: The results suggest that Lactobacillus plantarum supplementation could increase YOYO IR1 sports performance test scores and may mitigate TAC value reduction.

The main purpose of this systematic review and meta-analysis was to evaluate the effects of probiotics intake on strength and power performance in a trained population. This study was designed following Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement guidelines. The review was registered in PROSPERO with the following registration number: CRD42021248173. PubMed/MEDLINE, Web of Science, and Scopus databases were searched from their inception to the 18th March 2022 to find original research studies evaluating the effects of probiotic supplementation on strength and power performance tests in a trained population. The following inclusion criteria were applied to select studies: probiotics supplementation; trained population; strength and power performance measurements; human experimental trial; controlled with a placebo group; peer-reviewed and original articles written in English language. Random effects model and standardized mean differences (SMD) were used following Hedges’ G for the meta-analysis. Seven studies were finally included after the inclusion/exclusion criteria were applied (n=142 participants). Results of the meta-analysis identified a significant benefit of probiotics compared to placebo treatments (p=.04), with a small pooled effect size (SMD=0.36 [0.02-0.70]; I2=43%), and no funnel plot asymmetry was present. In summary, this systematic review and meta-analysis demonstrated that probiotic supplementation could effectively enhance strength and power performance in a trained population.