Best Practices for Probiotic Research in Athletic and Physically Active Populations: Guidance for Future Randomized Controlled Trials

Understanding the links between micro/nanoplastics-induced gut microbes dysbiosis and potential diseases in fish: A review

At present, the quantity of micro/nano plastics in the environment is steadily rising, and their pollution has emerged as a global environmental issue. The tendency of their bioaccumulation in aquatic organisms (especially fish) has intensified people's attention to their persistent ecotoxicology. This review critically studies the accumulation of fish in the intestines of fish through active or passive intake of micro/nano plastics, resulting in their accumulation in intestinal organs and subsequent disturbance of intestinal microflora. The key lies in the complex toxic effect on the host after the disturbance of fish intestinal microflora. In addition, this review pointed out the characteristics of micro/nano plastics and the effects of their combined toxicity with adsorbed pollutants on fish intestinal microorganisms, in order to fully understand the characteristics of micro/nano plastics and emphasize the complex interaction between MNPs and other pollutants. We have an in-depth understanding of MNPs-induced intestinal flora disorders and intestinal dysfunction, affecting the host's systemic system, including immune system, nervous system, and reproductive system. The review also underscores the imperative for future research to investigate the toxic effects of prolonged exposure to MNPs, which are crucial for evaluating the ecological risks posed by MNPs and devising strategies to safeguard aquatic organisms.

Supplementation with Lactiplantibacillus brevis GKEX Combined with Resistance Exercise Training Improves Muscle Mass, Strength Performance, and Body Fat Condition in Healthy Humans

In addition to maintaining good exercise and dietary habits, recent studies have shown that probiotics may have potential benefits for muscle mass and strength. It is worth noting that the effects may vary depending on the specific strains used. To date, no studies have analyzed the effects of Lactiplantibacillus brevis in this context. Here, we combine the L. brevis strain GKEX with resistance training to further understand its effects on muscle mass, thickness, performance, and fat loss. In a six-week intervention for a double-blind randomized trial, 52 healthy subjects were divided into two groups (10 male and 16 female participants in each group): a placebo group (two capsules/day, containing 0 CFU of GKEX per capsule) and a GKEX group (two capsules/day, containing 1 × 1010 CFU of GKEX per capsule). Before the intervention, no differences were observed between the two groups in any of the tests (body composition, muscle thickness, exercise performance, and blood parameters). However, supplementation with GKEX significantly improved muscle mass and thickness, as well as grip strength, muscle strength, and explosive performance, when compared to the associated parameters before the intervention. Additionally, GKEX supplementation promoted a reduction in the body fat percentage (p < 0.05). Through analysis of the change amount, we observed that GKEX supplementation yielded significantly improved benefits when compared to the placebo group (p < 0.05). In summary, our findings support the notion that a six-week resistance exercise training program combined with L. brevis GKEX supplementation has superior additive effects that enhance muscle mass and strength performance, while also reducing body fat percentage. This intervention can promote muscle gain and fat loss.

It's Dead! Can Postbiotics Really Help Performance and Recovery? A Systematic Review

In recent years, postbiotics have increased in popularity, but the potential relevancy of postbiotics for augmenting exercise performance, recovery, and health is underexplored. A systematic literature search of Google Scholar and PubMed databases was performed with the main objective being to identify and summarize the current body of scientific literature on postbiotic supplementation and outcomes related to exercise performance and recovery. Inclusion criteria for this systematic review consisted of peer-reviewed, randomized, double-blind, and placebo-controlled trials, with a population including healthy men or women >18 years of age. Studies required the incorporation of a postbiotic supplementation regimen and an outcome linked to exercise. Search terms included paraprobiotics, Tyndallized probiotics, ghost biotics, heat-killed probiotics, inactivated probiotics, nonviable probiotics, exercise, exercise performance, and recovery. Only investigations written in English were considered. Nine peer-reviewed manuscripts and two published abstracts from conference proceedings were included and reviewed. Supplementation periods ranged from 13 days to 12 weeks. A total of 477 subjects participated in the studies (n = 16-105/study) with reported results spanning a variety of exercise outcomes including exercise performance, recovery of lost strength, body composition, perceptual fatigue and soreness, daily logs of physical conditions, changes in mood states, and biomarkers associated with muscle damage, inflammation, immune modulation, and oxidative stress. Early evidence has provided some indication that postbiotic supplementation may help to support mood, reduce fatigue, and increase the readiness of athletes across several weeks of exercise training. However, more research is needed to further understand how postbiotics may augment health, resiliency, performance, and recovery. Future investigations should include longer supplementation periods spanning a wider variety of competitive athletes and exercising populations.

Impact of probiotic Veillonella atypica FB0054 supplementation on anaerobic capacity and lactate

Seven healthy, physically active men (n = 3) and women (n = 4) (30.7 ± 7.5 years, 172.7 ± 8.7 cm, 70.4 ± 11.6 kg, 23.6 ± 4.1 kg/m2, 49.2 ± 8.4 mL/kg/min) supplemented for 14 days with a placebo (PLA) or 1 × 1010 CFU doses of the probiotic Veillonella atypica FB0054 (FitBiomics, New York, NY). Participants had safety panels, hemodynamics, lactate, and anaerobic capacity assessed. Stool samples were collected to evaluate for metagenomic and metabolomic changes. Exhaustion times were not different between groups, whereas anaerobic capacity tended to shorten with PLA (61.14 ± 72.04 s; 95% CI: -5.49, 127.77 s, p = 0.066) with no change with VA (13.29 ± 100.13 s, 95% CI: -79.32, 105.89 s, p = 0.738). No changes in lactate, hemodynamics, or bacterial community changes were observed, whereas 14 metabolites exhibited differential expression patterns with VA supplementation. In conclusion, VA maintained exercise performance that tended to decline in PLA. Supplementation was well tolerated with no changes in safety markers or reported adverse events.

A systematic scoping review of study methodology for randomized controlled trials investigating probiotics in athletic and physically active populations

BACKGROUND

The purported ergogenic and health effects of probiotics have been a topic of great intrigue among researchers, practitioners, and the lay public alike. There has also been an increased research focus within the realm of sports science and exercise medicine on the athletic gut microbiota. However, compared to other ergogenic aids and dietary supplements, probiotics present unique study challenges. The objectives of this systematic scoping review were to identify and characterize study methodologies of randomized controlled trials investigating supplementation with probiotics in athletes and physically active individuals.

METHODS

Four databases (MEDLINE, CINAHL, Cochrane CENTRAL, and Cochrane Database of Systematic Reviews) were searched for randomized controlled studies involving healthy athletes or physically active individuals. An intervention with probiotics and inclusion of a control and/or placebo group were essential. Only peer-reviewed articles in English were considered, and there were no date restrictions. Results were extracted and presented in tabular form to detail study protocols, characteristics, and outcomes. Bias in randomized controlled trials was determined with the RoB 2.0 tool.

RESULTS

A total of 45 studies were included in the review, with 35 using a parallel group design and 10 using a cross-over design. Approximately half the studies used a single probiotic and the other half a multi-strain preparation. The probiotic dose ranged from 2 × 108 to 1 × 1011 colony forming units daily, and the length of intervention was between 7 and 150 days. Fewer than half the studies directly assessed gastrointestinal symptoms, gut permeability, or the gut microbiota. The sex ratio of participants was heavily weighted toward males, and only 3 studies exclusively investigated females. Low-level adverse events were reported in only 2 studies, although the methodology of reporting varied widely. The risk of bias was generally low, although details on randomization were lacking in some studies.

CONCLUSION

There is a substantial body of research on the effects of probiotic supplementation in healthy athletes and physically active individuals. Considerable heterogeneity in probiotic selection and dosage as well as outcome measures has made clinical and mechanistic interpretation challenging for both health care practitioners and researchers. Attention to issues of randomization of participants, treatments and interventions, selection of outcomes, demographics, and reporting of adverse events will facilitate more trustworthy interpretation of probiotic study results and inform evidence-based guidelines.

Recommendations to Improve Quality of Probiotic Systematic Reviews With Meta-Analyses

Importance

Systematic reviews and meta-analyses often report conflicting results when assessing evidence for probiotic efficacy, partially because of the lack of understanding of the unique features of probiotic trials. As a consequence, clinical decisions on the use of probiotics have been confusing.

Objective

To provide recommendations to improve the quality and consistency of systematic reviews with meta-analyses on probiotics, so evidence-based clinical decisions can be made with more clarity.

Evidence Review

For this consensus statement, an updated literature review was conducted (January 1, 2020, to June 30, 2022) to supplement a previously published 2018 literature search to identify areas where probiotic systematic reviews with meta-analyses might be improved. An expert panel of 21 scientists and physicians with experience on writing and reviewing probiotic reviews and meta-analyses was convened and used a modified Delphi method to develop recommendations for future probiotic reviews.

Findings

A total of 206 systematic reviews with meta-analysis components on probiotics were screened and representative examples discussed to determine areas for improvement. The expert panel initially identified 36 items that were inconsistently reported or were considered important to consider in probiotic meta-analyses. Of these, a consensus was reached for 9 recommendations to improve the quality of future probiotic meta-analyses.

Conclusions and Relevance

In this study, the expert panel reached a consensus on 9 recommendations that should promote improved reporting of probiotic systematic reviews with meta-analyses and, thereby, assist in clinical decisions regarding the use of probiotics.

Lactobacillus Bacteremia and Probiotics: A Review

Lactobacilli are widely found in nature, are commensal microbes in humans, and are commonly used as probiotics. Concerns about probiotic safety have arisen due to reports of bacteremia and other Lactobacillus-associated infections. We reviewed the literature for articles on the pathogenicity of Lactobacillus spp. bacteremia and reports of probiotics in these patients. Our aim is to review these articles and update the present knowledge on the epidemiology of Lactobacillus spp. bacteremia and determine the role of probiotics in Lactobacillus bacteremia. Lactobacillus bacteremia is infrequent but has a higher risk of mortality and risk factors, including severe underlying diseases, immune system suppression, admission to intensive care units, and use of central venous catheters. A variety of Lactobacillus species may cause bacteremia and may or may not be associated with probiotic exposure. To determine if oral probiotics are the source of these infections, the blood isolates and the oral probiotic strain(s) must be compared by sensitive identification methods. The prevalence of Lactobacillus bacteremia is infrequent but is more common in patients taking probiotics compared to those not taking probiotics. Three probiotics (Lacticaseibacillus rhamnosus GG, Lactiplantibacillus plantarum, and Lacticaseibacillus paracasei) were directly linked with blood isolates from bacteremia patients using molecular identification assays.

Orally Ingested Probiotic, Prebiotic, and Synbiotic Interventions as Countermeasures for Gastrointestinal Tract Infections in Nonelderly Adults: A Systematic Review and Meta-Analysis

Meta-analyses have not examined the prophylactic use of orally ingested probiotics, prebiotics, and synbiotics for preventing gastrointestinal tract infections (GTIs) of various etiologies in adult populations, despite evidence that these gut microbiota-targeted interventions can be effective in treating certain GTIs. This systematic review and meta-analysis aimed to estimate the effects of prophylactic use of orally ingested probiotics, prebiotics, and synbiotics on GTI incidence, duration, and severity in nonelderly, nonhospitalized adults. CENTRAL, PubMed, Scopus, and Web of Science were searched through January 2022. English-language, peer-reviewed publications of randomized, placebo-controlled studies testing an orally ingested probiotic, prebiotic, or synbiotic intervention of any dose for ≥1 wk in adults who were not hospitalized, immunosuppressed, or taking antibiotics were included. Results were analyzed using random-effects meta-analyses of intention-to-treat (ITT) and complete case (CC) cohorts. Heterogeneity was explored by subgroup meta-analysis and meta-regression. The risk of bias was assessed using the Cochrane risk-of-bias 2 tool. Seventeen publications reporting 20 studies of probiotics (n = 16), prebiotics (n = 3), and synbiotics (n = 1) were identified (n > 6994 subjects). In CC and ITT analyses, risk of experiencing ≥1 GTI was reduced with probiotics (CC analysis-risk ratio: 0.86; 95% CI: 0.73, 1.01) and prebiotics (risk ratio: 0.80; 95% CI: 0.66, 0.98). No effects on GTI duration or severity were observed. Sources of heterogeneity included the study population and number of probiotic strains administered but were often unexplained, and a high risk of bias was observed for most studies. The specific effects of individual probiotic strains and prebiotic types could not be assessed owing to a lack of confirmatory studies. Findings indicated that both orally ingested probiotics and prebiotics, relative to placebo, demonstrated modest benefit for reducing GTI risk in nonelderly adults. However, results should be interpreted cautiously owing to the low number of studies, high risk of bias, and unexplained heterogeneity that may include probiotic strain-specific or prebiotic-specific effects. This review was registered at PROSPERO as CRD42020200670.

Resistance Exercise Increases Gastrointestinal Symptoms, Markers of Gut Permeability, and Damage in Resistance-Trained Adults

PURPOSE

This study aimed to determine the influence of acute resistance exercise (RE) and biological sex on subjective gastrointestinal (GI) symptoms, GI epithelial damage, and GI permeability in resistance-trained males and females.

METHODS

Thirty resistance-trained men ( n = 15) and women ( n = 15) completed an RE bout and a nonexercise control (CON) session in a randomized counterbalanced design. The RE protocol used a load of 70% one-repetition maximum for 4 sets of 10 repetitions with a 90-s rest period length between sets and a 120-s rest period between exercises (squat, seated shoulder press, deadlift, bent-over row, and leg press). Blood samples were collected before exercise (PRE), immediately postexercise (IP), and 15-, 30-, and 60-min postexercise. Participants completed GI symptom questionnaires to assess subjective GI symptoms PRE, IP, and 60-min postexercise. Blood samples were assayed to quantify small intestine damage (I-FABP) and GI permeability (lactulose-rhamnose [L/R] ratio). Data were analyzed via separate repeated-measures ANOVA, and area under the curve (AUC) analyses were completed via one-way ANOVA.

RESULTS

Participants reported greater GI symptoms in RE at IP compared with CON ( P < 0.001) with 70% of participants reporting at least one GI symptom with no differences between sexes. Nausea was the most reported GI symptom (63.3%), followed by vomiting (33.3%). I-FABP and L/R ratio did not exhibit differential responses between conditions. However, L/R ratio AUC was greater in males after RE than male CON ( P = 0.002) and both conditions for females ( P < 0.05). Furthermore, I-FABP AUC in the male RE condition was greater than both female conditions ( P < 0.05).

CONCLUSIONS

Resistance-trained individuals experience GI distress after RE, with males incurring the greatest increases in markers of GI damage and permeability.