Stratification of athletes' gut microbiota: the multifaceted hubs associated with dietary factors, physical characteristics and performance

Skin bacterial community dynamics of hands and forearms before and after military field exercise

The human skin microbiome is crucial for health and immunity, especially under the extreme conditions military personnel face. Soldiers often encounter unique stressors and hygienic challenges that can alter their skin's microbial composition, particularly in field environments. In this study, we aimed to investigate the impact of military field exercises on the diversity and composition of the skin bacterial microbiota using 16S rRNA sequencing. We conducted a longitudinal study of Norwegian soldiers (n = 19) participating in outdoor training operations during the NATO winter exercise Cold Response 2022. Skin swabs were taken from soldiers' hands and forearms before and after the 10-day military exercise, and following a 3-week post-exercise leave. Our results reveal hand- and forearm-specific shifts in bacterial populations associated with the exercise, likely influenced by environmental exposure, reduced hygiene, and heightened social contact. Alpha diversity increased on forearms while remaining stable on hands, which appeared more resilient to perturbations. Both sites exhibited temporal changes in composition, with soil- and water-associated bacteria enriched post-exercise; most being transient on hands but more sustained on forearms. The soldiers' microbiomes converged during the exercise, then diverged in the post-exercise leave period, and neither skin site returned to baseline composition at follow-up. Our findings highlight the impact of collaborative outdoor activities on microbial communities and suggest that resilience and stability differ between skin sites.IMPORTANCEOptimizing soldier health and resilience is critical for maintaining military readiness and operational effectiveness. The skin, as the body's first line of defense, is subjected to numerous challenges in military environments. Unique environmental and hygiene challenges can disrupt the skin microbiome and increase susceptibility to skin and soft tissue infections. This longitudinal research provides valuable insights into the effects of military service on the bacterial dynamics of the skin microbiome but can also inform hygiene management and disease prevention in comparable situations.

Roles of the gut microbiota in hepatocellular carcinoma: from the gut dysbiosis to the intratumoral microbiota

Hepatocellular carcinoma (HCC) is closely linked to alterations in the gut microbiota. This dysbiosis is characterized by significant changes in the microbial population, which correlate with the progression of HCC. Gut dysbiosis ultimately promotes HCC development in several ways: it damages the integrity of the gut-vascular barrier (GVB), alters the tumor microenvironment (TME), and even affects the intratumoral microbiota. Subsequently, intratumoral microbiota present a characteristic profile and play an essential role in HCC progression mainly by causing DNA damage, mediating tumor-related signaling pathways, altering the TME, promoting HCC metastasis, or through other mechanisms. Both gut microbiota and intratumoral microbiota have dual effects on HCC progression; a comprehensive understanding of their complex biological roles will provide a theoretical foundation for potential clinical applications in HCC treatment.

Caffeine and Beetroot Juice Optimize 1,000-m Performance: Shapley Additive Explanations Analysis

The 1,000-m run is a key component of university physical fitness assessments. Effective supplementation strategies to enhance performance and recovery in this test remain underexplored. This study aimed to evaluate the effects of caffeine (CAF) and beetroot juice (BJ) on 1,000-m performance and used SHapley Additive exPlanations (SHAP) analysis to identify key influencing factors. A randomized crossover design compared the effects of CAF (6 mg/kg body weight), BJ (70 mL providing 6.4 mmol of NO 3 - ), and their combination with placebo (PLA) on 1,000-m running performance. Twenty healthy male participants took part in the study. Physiological, nutritional, and behavioral data were collected during each condition. SHAP analysis of a multilayer perceptron model quantified the relative importance of various performance determinants, providing a clear assessment of their contribution to the outcome. The CAF + BJ group performed significantly better than PLA (p < .01) in the first 1,000-m run and outperformed both PLA and BJ in the second run (p < .01). Performance declined after recovery in BJ (p < .01) and PLA (p < .01) but improved in CAF + BJ (p < .01). Post-exercise heart rate and blood lactate were highest in CAF + BJ and CAF, with CAF showing significantly higher lactate levels at 10, 15, and 20 min post-exercise compared to CAF + BJ (p < .01). SHAP analysis ranked body fat percentage > weight > age > nighttime sleep duration > nutritional strategy > average vertical jump height > grip strength > resting heart rate > time since last meal > alcohol consumption > height > smoking frequency. This study suggests that CAF and BJ supplementation may improve 1,000-m performance. SHAP analysis introduced a novel framework for identifying key factors, offering insights for targeted interventions. Tailored dietary supplement strategies that address critical physiological and lifestyle factors are important. Combining supplementation with these approaches can further enhance performance and recovery.

Gut Microbiota Alteration with Moderate-to-Vigorous-Intensity Exercise in Middle School Female Football Athletes

BACKGROUND

The gut microbiota significantly influences health and metabolic processes. This study aimed to investigate the impact of exercise intensity on the gut microbiota of middle school female football athletes.

METHODS

In this four-week controlled comparative study, twenty-nine participants were divided into three groups: non-exercise group (NEG), moderate-intensity exercise group (MIEG), and vigorous-intensity exercise group (VIEG). They followed their respective exercise regimens for four weeks. Fecal samples were collected for 16S rRNA gene sequencing to evaluate microbiota composition.

RESULTS

The MIEG exhibited significantly greater microbial diversity compared to the NEG, while the VIEG showed lower diversity than the MIEG. Various microbiota profiles were identified, with the MIEG having higher levels of beneficial bacteria such as Bacteroides.

CONCLUSIONS

Moderate-intensity exercise promotes a healthier gut microbiota compared to vigorous exercise in young female athletes. These findings underscore the potential of moderate exercise to enhance gut health and may inform training strategies for adolescent athletes.

Differential Gut Microbiome Profiles in Long-Distance Endurance Cyclists and Runners

We recently have shown that the gut microbiota composition in female and male runners positively correlates with sports, and female runners show similar gut microbiome diversity to male runners. However, gut microbiota composition has not yet been fully investigated in other endurance athletes, such as cyclists. Therefore, in the current study, we investigated the gut microbiome profiles in competitive, non-professional female and male cyclists compared to what we have shown in runners. We aim to understand (1) whether the gut microbiome signature is sport-specific; (2) whether there is a microbiome difference between female and male cyclists and runners; and (3) whether the gut bacteria expressed in cyclists and runners correlates with exercise performance. Our study included 58 subjects: 18 cyclists (9 males), 22 runners (13 males), and 18 control subjects (9 males). Fecal samples were obtained and subjected to taxonomic analysis to assess the relative abundances of species across subjects based on 16S rRNA sequencing results. Both alpha and beta diversity of the bacterial communities were evaluated to identify compositional variations between the groups. Each participant completed a maximal oxygen consumption test and a time-to-exhaustion test at 85% of the measured VO2max. Cyclists performed the test on an SRM ergometer, while runners used a motorized treadmill. Blood lactate levels were measured at 5 min intervals throughout the time-to-exhaustion trials. Alpha diversity demonstrated a significant difference (p-adj < 0.001) between cyclists and runners. Male cyclists showed significantly lower alpha diversity than runners (p-adj < 0.001). The taxonomic analysis of gut microbiota composition between cyclists, runners, and controls showed a lower or higher abundance of fifteen different bacteria. In cyclists, there was a significant positive correlation between six bacteria, and in runners, there was a significant positive correlation between eight bacteria, with weekly training volume, time-to-exhaustion, VO2max, and blood lactate levels. This study suggests potential sport-specific characteristics in long-distance cyclists' and runners' gut microbiome signatures. These findings emphasize the differences in gut microbiota between cyclists and runners, probably due to the difference in physiological and biomechanical conditions related to the activity mode during each sport.

Microbial Champions: The Influence of Gut Microbiota on Athletic Performance via the Gut-Brain Axis

In recent years, exercise has shown a powerful ability to regulate the gut microbiota received with concern. For instance, compared with the sedentary group, high-level athletes showed a different gut microbiota composition and remarkable capability of physiological metabolism. In addition, different diet patterns (eg, high-fat diet, high carbohydrate diet et.al) have different effects on gut microbiota, which can also affect exercise performance. Furthermore, adaptations to exercise also might be influenced by the gut microbiota, due to its important role in the transformation and expenditure of energy obtained from the diet. Therefore, appropriate dietary supplementation is important during exercise. And exploring the mechanisms by which dietary supplements affect exercise performance by modulating gut microbiota is of considerable interest to athletes wishing to achieve health and athletic performance. In this narrative review, the relationship between gut microbiota, dietary supplements, training adaptations and performance is discussed as follows. (i) The effects of the three main nutritional supplements on gut microbiota and athlete fitness. (ii) Strategies for dietary supplements and how they exerted function through gut microbiota alteration based on the gut-brain axis. (iii) Why dietary supplement interventions on gut microbiota should be tailored to different types of exercise. Our work integrates these factors to elucidate how specific nutritional supplements can modulate gut microbiota composition and, consequently, influence training adaptations and performance outcomes, unlike previous literature that often focuses solely on the effects of exercise or diet independently. And provides a comprehensive framework for athletes seeking to optimize their health and performance through a microbiota-centric approach.

Fibrolytic efficiency of the large intestine microbiota may benefit running speed in French trotters: A pilot study

This pilot study sought to explore the contribution of the large intestine microbiota to energy metabolism and exercise performance through its ability to degrade fibers into short-chain fatty acids (SCFAs). To investigate this, a correlational study was carried out on athlete horses under the same management conditions. Fecal microbiota diversity and composition, fibrolytic efficiency and SCFAs were analyzed. An incremental running test was carried out to estimate the maximal running speed (MRS) of the horses, and blood samples were taken to measure energy metabolism parameters. MRS was positively correlated with the efficiency of the fecal microbiota in degrading cellulose in vitro (r = 0.51; p = 0.02). The abundance of fibrolytic bacterial taxa was not associated with MRS, but functional inference analysis revealed a positive association between MRS and pathways potentially related to fibrolytic activity (r = 0.54; p = 0.07 and r = 0.56; p = 0.05 for butyrate metabolism and thiamine metabolism, respectively). In contrast, the metabolic pathway of starch degradation appeared negatively associated with MRS (r = -0.55; p = 0.06). The present findings suggest a potential contribution of the large intestine microbiota and dietary fibers digestion to exercise capacity in equine athletes.

Physical activity, sedentary behavior and microbiome: A systematic review and meta-analysis

BACKGROUND

The effects of physical activity and sedentary behavior on human health are well known, however, the molecular mechanisms are poorly understood. Growing evidence points to physical activity as an important modulator of the composition and function of microbial communities, while evidence of sedentary behavior is scarce. We aimed to synthesize and meta-analyze the current evidence about the effects of physical activity and sedentary behavior on microbiome across different body sites and in different populations.

METHODS

A systematic search in PubMed, Web of Science, Scopus and Cochrane databases was conducted until September 2022. Random-effects meta-analyses including cross-sectional studies (active vs. inactive/athletes vs. non-athletes) or trials reporting the chronic effect of physical activity interventions on gut microbiome alpha-diversity in healthy individuals were performed.

RESULTS

Ninety-one studies were included in this systematic review. Our meta-analyses of 2632 participants indicated no consistent effect of physical activity on microbial alpha-diversity, although there seems to be a trend toward a higher microbial richness in athletes compared to non-athletes. Most of studies reported an increase in short-chain fatty acid-producing bacteria such as Akkermansia, Faecalibacterium, Veillonella or Roseburia in active individuals and after physical activity interventions.

CONCLUSIONS

Physical activity levels were positively associated with the relative abundance of short-chain fatty acid-producing bacteria. Athletes seem to have a richer microbiome compared to non-athletes. However, high heterogeneity between studies avoids obtaining conclusive information on the role of physical activity in microbial composition. Future multi-omics studies would enhance our understanding of the molecular effects of physical activity and sedentary behavior on the microbiome.

Physical Exercise and the Gut Microbiome: A Bidirectional Relationship Influencing Health and Performance

Background/Objectives: The human gut microbiome is a complex ecosystem of microorganisms that can influence our health and exercise habits. On the other hand, physical exercise can also impact our microbiome, affecting our health. Our narrative review examines the bidirectional relationship between physical activity and the gut microbiome, as well as the potential for targeted probiotic regimens to enhance sports performance. Methods: We conducted a comprehensive literature review to select articles published up till January 2024 on the topics of physical exercise, sports, probiotics, and gut microbiota from major scientific databases, incorporating over 100 studies. Results: We found that the impact of physical activity on the gut microbiome varies with the type and intensity of exercise. Moderate exercise promotes a healthy immune system, while high-intensity exercise for a long duration can cause a leaky gut and consequent systemic inflammation, which may disrupt the microbial balance. Combining aerobic and resistance training significantly affects bacterial diversity, linked to a lower prevalence of chronic metabolic disorders. Furthermore, exercise enhances gut microbiome diversity, increases SCFA production, improves nutrient utilization, and modulates neural and hormonal pathways, improving gut barrier integrity. Our findings also showed probiotic supplementation is associated with decreased inflammation, enhanced sports performance, and fewer gastrointestinal disturbances, suggesting that the relationship between the gut microbiome and physical activity is mutually influential. Conclusions: The bidirectional relationship between physical activity and the gut microbiome is exemplified by how exercise can promote beneficial bacteria while a healthy gut microbiome can potentially enhance exercise ability through various mechanisms. These findings underscore the importance of adding potential tailored exercise regimens and probiotic supplementation that consider individual microbiome profiles into exercise programs.

Comparative analyses of gut microbiota reveal ammonia detoxification and nitrogen assimilation in Cyprinus carpio var. specularis

The complex niche of fish gut is often characterized by the associated microorganisms that have implications in fish gut-health nexus. Although efforts to distinguish the microbial communities have highlighted their disparate structure along the gut length, remarkably little information is available about their distinct structural and functional profiles in different gut compartments in different fish species. Here, we performed comparative taxonomic and predictive functional analyses of the foregut and hindgut microbiota in an omnivorous freshwater fish species, Cyprinus carpio var. specularis, commonly known as mirror carp. Our analyses showed that the hindgut microbiota could be distinguished from foregut based on the abundance of ammonia-oxidizing, denitrifying, and nitrogen-fixing commensals of families such as Rhodospirillaceae, Oxalobacteraceae, Nitrosomonadaceae, and Nitrospiraceae. Functionally, unique metabolic pathways such as degradation of lignin, 2-nitrobenzoate, vanillin, vanillate, and toluene predicted within hindgut also hinted at the ability of hindgut microbiota for assimilation of nitrogen and detoxification of ammonia. The study highlights a major role of hindgut microbiota in assimilating nitrogen, which remains to be one of the limiting nutrients within the gut of mirror carp.

Based on Sportomics: Comparison of Physiological Status of Collegiate Sprinters in Different Pre-Competition Preparation Periods

This study aimed to assess the impact of pre-competition training by comparing the differences of collegiate sprinters in physiological state between strengthening and tapering training period by sportomics and combining their sport performance. Fifteen collegiate sprinters were investigated or tested on their body composition, dietary habits, energy expenditure, sleep efficiency, heart rate and respiratory rate during training, blood (blood cells, biochemical and immune markers) and urine (urinalysis), gut microbiome distribution, microbiome and blood metabolites, and their functions during the strengthening (Group A) and tapering training period (Group B) prior to competing in the national competitions. We found that 26.67% of sprinters achieved personal bests (PB) after the competition. The limb skeletal muscle mass and lymphocyte ratio of male sprinters in Group B were lower than those in Group A, and the serum creatine kinase (CK) level was higher than Group A (p < 0.05). The levels of serum CK, interleukin-6 (IL-6), interleukin-1β (IL-1β), and urine-specific gravity (SG) of the two groups were higher than the upper limit of the reference value. The detection rates of urine white blood cell (WBC) and protein in Group B were higher than those in Group A. The gut microbiome health index (GMHI) of Group A was higher than that of Group B, and the microbial dysbiosis index was lower than that of Group B. The ratio of Firmicutes/Bacteroidota (F/B) in Group A was higher than that in Group B. There were 65 differential metabolites in the A/B group, and the enriched pathway was mainly the NF-kappa B signaling pathway (up); B/T cell receptor signaling pathway (up); Th1 and Th2 cell differentiation (up); phenylalanine metabolism (up); and growth hormone synthesis, secretion, and action (up). There were significant differences in blood metabolites between the A and B groups, with a total of 89 differential metabolites, and the enriched pathway was mainly the NF-kappa B signaling pathway (up), T cell receptor signaling pathway (up), Th1 and Th2 cell differentiation (up), and glycerophospholipid metabolism (down). In conclusion, the imbalance of the gut microbiome and inflammation and immune-related metabolites of collegiate sprinters during the pre-competition tapering training period may be the cause of their limited sports performance.

The Role of Gut Microbiota in Different Types of Physical Activity and Their Intensity: Systematic Review and Meta-Analysis

BACKGROUND

Intense exercise during training requires dietary modulation to support health and performance and differs in different types of activities. Diet, supplementation with prebiotics and probiotics, and, more recently, even physical activity can potentially improve health outcomes by modifying and protecting the gut microbiota. A systematic review and meta-analysis were conducted to investigate the modulation of gut microbiota in different types and intensities of physical activity and different lifestyles of athletes.

METHODS

The systematic review and meta-analysis were conducted according to the PRISMA guidelines, and the protocol was registered in PROSPERO (CRD42024500826).

RESULTS

Out of 1318 studies, only 10 met the criteria for inclusion in the meta-analysis. The pilot study's meta-regression analysis highlights the role of type and intensity of exercise in changing the B/B (Bacillota/Bacteroidota) ratio (p = 0.001).

CONCLUSIONS

As gut training becomes more popular among athletes, it is necessary to map interactions between microbiota and different types of physical activity, personalized diets, physical activities, and ergogenic supplements to enhance performance and athletic wellness.

Microbiome and physical activity

Regular physical activity promotes health benefits and contributes to develop the individual biological potential. Chronical physical activity performed at moderate and high-intensity is the intensity more favorable to produce health development in athletes and improve the gut microbiota balance. The athletic microbiome is characterized by increased microbial diversity and abundance as well as greater phenotypic versatility. In addition, physical activity and microbiota composition have bidirectional effects, with regular physical activity improving microbial composition and microbial composition enhancing physical performance. The improvement of physical performance by a healthy microbiota is related to different phenotypes: i) efficient metabolic development, ii) improved regulation of intestinal permeability, iii) favourable modulation of local and systemic inflammatory and efficient immune responses, iv) efective regulation of systemic pH and, v) protection against acute stressful events such as environmental exposure to altitude or heat. The type of sport, both intensity or volume characteristics promote microbiota specialisation. Individual assessment of the state of the gut microbiota can be an effective biomarker for monitoring health in the medium to long term. The relationship between the microbiota and the rest of the body is bidirectional and symbiotic, with a full connection between the systemic functions of the nervous, musculoskeletal, endocrine, metabolic, acid-base and immune systems. In addition, circadian rhythms, including regular physical activity, directly influence the adaptive response of the microbiota. In conclusion, regular stimuli of moderate- and high-intensity physical activity promote greater diversity, abundance, resilience and versatility of the gut microbiota. This effect is highly beneficial for human health when healthy lifestyle habits including nutrition, hydration, rest, chronoregulation and physical activity.

Summatory Effects of Anaerobic Exercise and a 'Westernized Athletic Diet' on Gut Dysbiosis and Chronic Low-Grade Metabolic Acidosis

Anaerobic exercise decreases systemic pH and increases metabolic acidosis in athletes, altering the acid-base homeostasis. In addition, nutritional recommendations advising athletes to intake higher amounts of proteins and simple carbohydrates (including from sport functional supplements) could be detrimental to restoring acid-base balance. Here, this specific nutrition could be classified as an acidic diet and defined as 'Westernized athletic nutrition'. The maintenance of a chronic physiological state of low-grade metabolic acidosis produces detrimental effects on systemic health, physical performance, and inflammation. Therefore, nutrition must be capable of compensating for systemic acidosis from anaerobic exercise. The healthy gut microbiota can contribute to improving health and physical performance in athletes and, specifically, decrease the systemic acidic load through the conversion of lactate from systemic circulation to short-chain fatty acids in the proximal colon. On the contrary, microbial dysbiosis results in negative consequences for host health and physical performance because it results in a greater accumulation of systemic lactate, hydrogen ions, carbon dioxide, bacterial endotoxins, bioamines, and immunogenic compounds that are transported through the epithelia into the blood circulation. In conclusion, the systemic metabolic acidosis resulting from anaerobic exercise can be aggravated through an acidic diet, promoting chronic, low-grade metabolic acidosis in athletes. The individuality of athletic training and nutrition must take into consideration the acid-base homeostasis to modulate microbiota and adaptive physiological responses.

Divergent Gut Microbiota: Archaeal and Bacterial Signatures Unveil Unique Patterns in Colombian Cyclists Compared to Weightlifters and Non-Athletes

Engagement in physical activity, across various sports, promotes a diverse microbiota in active individuals. This study examines the gut microbiota of Colombian athletes, specifically weightlifters (n = 16) and road cyclists (n = 13), compared to non-athletes (n = 15). Using Kruskal-Wallis tests, the physical activity level of a group of non-athletic individuals and the sports experience of a group of professional athletes is analyzed. The median age of participants is 24 years, comprising 25 men and 19 women. The microbiota is collected using fecal samples. Participants provided these samples during their pre-competitive stage, specifically during the concentration phase occurring two weeks prior to national competitions. This timing is chosen to capture the microbial composition during a period of heightened physical preparation. Questionnaire responses and microbial composition assessments identify disparities among groups. Microbial composition analysis explores core microbiome, abundance, and taxonomy using Pavian, MicrobiomeAnalyst 2.0, and GraPhlAn. ANCOM-BC2 reveals differentially abundant species. Road cyclists exhibit decreased Bacteria and increased Archaea abundance. Phylum-level variations included Planctomycetes, Acidobacteria, and Proteobacteria, while Bacteroidetes prevailed. Key families influencing gut microbiota are Bacteroidaceae, Muribaculaceae, and Selenomonadaceae. Weightlifters exhibit unique viral and archaeal community connections, while cyclists showed specialized microbial interplay influenced by endurance exercise. Correlation network analysis emphasizes distinctive microbial interactions within athlete groups, shedding light on the impact of physical activities on gut microbiota and athlete health.

The effect of Phyllanthus emblica (Amla) fruit supplementation on the rumen microbiota and its correlation with rumen fermentation in dairy cows

Introduction

Medicinal plants, rich in phytochemicals like phenolic acids, flavonoids, and tannins, offer potential benefits in enhancing productivity, quality, and animal health. Amla fruit (Phyllanthus emblica) is one such plant with promising attributes. This study aimed to investigate the impact of fresh Amla fruit (FAF) supplementation on ruminal microbial composition and its correlation with rumen fermentation in lactating dairy cows.

Methods

The study employed a repeated crossover design involving eight ruminally cannulated mid-lactation Holstein dairy cows. Animals received varying levels of fresh Amla fruit supplementation (0, 200, 400, and 600 g/d).

Results

When 400 g/d of FAF was added to the diet, there was a significant increase in the relative abundance of Firmicutes (p = 0.02). However, at 200 g/d, the relative abundance of ruminal Bacteroidota was higher than the 0 and 400 g/d FAF supplementation (p < 0.01). LEfSe analysis identified distinct taxa, such as Clostridia vadinBB60 in the 200 g/d group, Oscillospiraceae in the 400 g/d group, and Elusimicrobium in the 600 g/d group. Notably, the random forest species abundance statistics identified Oscillospiraceae V9D2013 as a biomarker related to milk yield. Oscillospiraceae, Bacilli RF39, norank_f Prevotellaceae, and Bifidobacterium were positively correlated with ruminal total VFA and molar proportion of propionate, while Rikenellaceae RC9 gut group and Clostridia vadinBB60 were negatively correlated.

Discussion

FAF supplementation affects the abundance of beneficial microbes in a dose-dependent manner, which can improve milk yield, efficiency, rumen health, desirable fatty acids, and animal health.

Exercise-induced microbial changes in preventing type 2 diabetes

The metabolic benefits associated with long-term physical activity are well appreciated and growing evidence suggests that it involves the gut microbiota. Here we re-evaluated the link between exercise-induced microbial changes and those associated with prediabetes and diabetes. We found that the relative abundances of substantial amounts of diabetes-associated metagenomic species associated negatively with physical fitness in a Chinese athlete students cohort. We additionally showed that those microbial changes correlated more with handgrip strength, a simple but valuable biomarker suggestive of the diabetes states, than maximum oxygen intake, one of the key surrogates for endurance training. Moreover, the causal relationships among exercise, risks for diabetes, and gut microbiota were explored based on mediation analysis. We propose that the protective roles of exercise against type 2 diabetes are mediated, at least partly, by the gut microbiota.

The impact of exercise on the gut microbiota in middle-aged amateur serious runners: a comparative study

Introduction

Exercise, health, and the gut microbiota (GM) are strongly correlated. Research indicates that professional athletes, especially ultra-marathon runners, have unique GM characteristics. However, more research has focused on elite athletes, with little attention given to amateur sports enthusiasts, especially those in the middle-aged population. Therefore, this study focuses on the impact of long-term running on the composition and potential functions of the GM in middle-aged individuals.

Methods

We compared the GM of 25 middle-aged serious runnerswith 22 sedentary healthy controls who had minimal exercise habitsusing 16S rRNA gene sequencing. Additionally, we assessed dietary habits using a food frequency questionnaire.

Results and Discussion

Statistical analysis indicates that there is no significant difference in dietary patterns between the control group and serious runners. Diversity analysis results indicate that there is no significant difference in α diversity between the two groups of GM, but there is a significant difference in β diversity. Analysis of the composition of GM reveals that Ruminococcus and Coprococcus are significantly enriched in serious runners, whereas Bacteroides, Lachnoclostridium, and Lachnospira are enriched in the control group. Differential analysis of functional pathway prediction results reveals significant differences in the functional metabolism levels of GM between serious runners and the control group. Further correlation analysis results indicate that this difference may be closely related to variations in GM. In conclusion, our results suggest that long-term exercise can lead to changes in the composition of the GM. These changes have the potential to impact the overall health of the individual by influencing metabolic regulation.

An Exploratory Study on Seasonal Variation in the Gut Microbiota of Athletes: Insights from Japanese Handball Players

Despite accumulating evidence that suggests a unique gut microbiota composition in athletes, a comprehensive understanding of this phenomenon is lacking. Furthermore, seasonal variation in the gut microbiota of athletes, particularly during the off-season, remains underexplored. This study aimed to compare the gut microbiotas between athletic subjects (AS) and non-athletic subjects (NS), and to investigate variations between athletic and off-season periods. The data were derived from an observational study involving Japanese male handball players. The results revealed a distinct gut microbiota composition in AS compared with NS, characterized by significantly higher alpha-diversity and a greater relative abundance of Faecalibacterium and Streptococcus. Moreover, a comparative analysis between athletic and off-season periods in AS demonstrated a significant change in alpha-diversity. Notably, AS exhibited significantly higher alpha-diversity than NS during the athletic season, but no significant difference was observed during the off-season. This study demonstrates the characteristics of the gut microbiota of Japanese handball players and highlights the potential for changes in alpha-diversity during the off-season. These findings contribute to our understanding of the dynamic nature of the gut microbiota of athletes throughout the season.

What if gastrointestinal complications in endurance athletes were gut injuries in response to a high consumption of ultra-processed foods? Please take care of your bugs if you want to improve endurance performance: a narrative review

To improve performance and recovery faster, athletes are advised to eat more often than usual and consume higher doses of simple carbohydrates, during and after exercise. Sports energetic supplements contain food additives, such as artificial sweeteners, emulsifiers, acidity regulators, preservatives, and salts, which could be harmful to the gut microbiota and impair the intestinal barrier function. The intestinal barrier plays a critical function in bidirectionally regulation of the selective transfer of nutrients, water, and electrolytes, while preventing at the same time, the entrance of harmful substances (selective permeability). The gut microbiota helps to the host to regulate intestinal homeostasis through metabolic, protective, and immune functions. Globally, the gut health is essential to maintain systemic homeostasis in athletes, and to ensure proper digestion, metabolization, and substrate absorption. Gastrointestinal complaints are an important cause of underperformance and dropout during endurance events. These complications are directly related to the loss of gut equilibrium, mainly linked to microbiota dysbiosis and leaky gut. In summary, athletes must be cautious with the elevated intake of ultra-processed foods and specifically those contained on sports nutrition supplements. This review points out the specific nutritional interventions that should be implemented and/or discontinued depending on individual gut functionality.

The maternal gut microbiome in pregnancy: implications for the developing immune system

The gut microbiome has important roles in host metabolism and immunity, and microbial dysbiosis affects human physiology and health. Maternal immunity and microbial metabolites during pregnancy, microbial transfer during birth, and transfer of immune factors, microorganisms and metabolites via breastfeeding provide critical sources of early-life microbial and immune training, with important consequences for human health. Only a few studies have directly examined the interactions between the gut microbiome and the immune system during pregnancy, and the subsequent effect on offspring development. In this Review, we aim to describe how the maternal microbiome shapes overall pregnancy-associated maternal, fetal and early neonatal immune systems, focusing on the existing evidence and highlighting current gaps to promote further research.

Temporal and geographic distribution of gut microbial enterotypes associated with host thermogenesis characteristics in plateau pikas

IMPORTANCE

The gut microbiotas of small mammals play an important role in host energy homeostasis. However, it is still unknown whether small mammals with different enterotypes show differences in thermogenesis characteristics. Our study confirmed that plateau pikas with different bacterial enterotypes harbored distinct thermogenesis capabilities and employed various strategies against cold environments. Additionally, we also found that pikas with different fungal enterotypes may display differences in coprophagy.

Influence of the 2000-m ergometer test on indirect markers of intestinal injury in competitive elite rowers in different training phases

BACKGROUND

We examined the effect of the 2000-m ergometer test on gut injury in competitive elite rowers in two different training phases. Given that inflammatory markers during the competitive phase are higher, we hypothesise that markers of intestinal injury are also more elevated during that phase.

METHODS

We performed this study during the preparatory phase (Test I) and competitive phase (Test II) of annual training. We included 10 competitive elite rowers, members of the Polish Rowing Team, in the study after applying the inclusion/exclusion criteria. The participants performed a 2000-m ergometer test during both phases (Tests I and II). We collected blood samples before the test, immediately after the test and after 1 h of recovery. We measured the levels of interleukin 6 (IL-6), intestinal fatty acid binding protein (I-FABP), lipopolysaccharide (LPS), lipopolysaccharide-binding protein (LBP), and zonulin.

RESULTS

There were no significant changes over time in Test I and Test II in the gut integrity markers. There were significantly lower I-FABP and IL-6 levels after the test for Test II compared with Test I. The pre-test LPS level was significantly lower for Test II compared with Test I. The pre-test LBP and zonulin levels were numerically lower in Test II, but the differences were not significant.

CONCLUSIONS

The 2000-m ergometer test showed no influence on gut integrity markers. However, there were differences in the response to exercise between Tests I and II. The lower level of gut injury markers after extreme exercise tests carried out during the preparation period may be the result of adaptive mechanisms and could indicate that rationally conducted training significantly decreases intestinal injury.

Changes in gut microbiota composition after 12 weeks of a home-based lifestyle intervention in breast cancer survivors during the COVID-19 lockdown

Background

Breast cancer (BC) is the second-leading cause of cancer-related death worldwide. This study aimed to investigate the effects of a 12-week home-based lifestyle intervention (based on nutrition and exercise) on gut microbial composition in twenty BC survivors of the MoviS clinical trial (protocol: NCT04818359).

Methods

Gut microbiota analysis through 16S rRNA gene sequencing, anthropometrics, Mediterranean Diet (MD) adherence, and cardiometabolic parameters were evaluated before (Pre) and after (Post) the lifestyle intervention (LI).

Results

Beneficial effects of the LI were observed on MD adherence, and cardiometabolic parameters (pre vs post). A robust reduction of Proteobacteria was observed after LI, which is able to reshape the gut microbiota by modulating microorganisms capable of decreasing inflammation and others involved in improving the lipid and glycemic assets of the host. A significant negative correlation between fasting glucose and Clostridia_vadinBB60 (r = -0.62), insulin and homeostatic model assessment (HOMA) index and Butyricicoccus genera (r = -0.72 and -0.66, respectively), and HDL cholesterol and Escherichia/Shigella (r = -0.59) have been reported. Moreover, positive correlations were found between MD adherence and Lachnospiraceae_ND3007 (r = 0.50), Faecalibacterium (r = 0.38) and Butyricimonas (r = 0.39).

Conclusion

These data suggest that adopting a healthy lifestyle, may contribute to ameliorate several biological parameters that could be involved in the prevention of cancer relapses through the modulation of gut microbiota.

The Muscle-Gut-Brain Axis and Psychiatric Illness

The microbiota-gut-brain axis (MGBA) has been the subject of much research over the past decade, offering an exciting new paradigm for the treatment of psychiatric disorders. In this review, the MGBA is extended to include skeletal muscle and the potential role of an expanded "muscle-gut-brain axis" (MuGBA) in conditions such as anxiety and depression is discussed. There is evidence, from both preclinical and human studies, of bidirectional links between the gut microbiome and skeletal muscle function and structure. The therapeutic role of exercise in reducing depressive and anxiety symptoms is widely recognised, and the potential role of the gut microbiota-skeletal muscle link is discussed within this context. Potential pathways of communication involved in the MuGBA including the tryptophan-kynurenine pathway, intestinal permeability, immune modulation, and bacterial metabolites such as short-chain-fatty-acids are explored.

Lactiplantibacillus Plantarum CCFM8724 Reduces the Amounts of Oral Pathogens and Alters the Oral Microbiota in Children With Dental Caries: a Randomized, Double-Blind, Placebo-Controlled Trial

Objective Early childhood caries (ECC) is closely related to the disorders of oral microbiota. Probiotics antagonize pathogenic bacteria and regulate the composition of the microbiota. We aimed to investigate the effects of Lactiplantibacillus plantarum CCFM8724 on Streptococcus mutans, Candida albicans, and oral microbiota of patients.Methods Children with ECC aged 3‒6 years were randomly divided into probiotic and placebo groups in the double-blind controlled trial. The intervention and washout periods were 28 days and 14 days, respectively. On days 1 and 28, dental plaques were collected. The effects of L. plantarum CCFM8724 on the oral microbiota of patients were investigated by sequencing the V3-V4 region of 16S rDNA. On days 1, 14, 28 and 42, qPCR was used to investigate the effect of L. plantarum CCFM8724 on the amounts of S. mutans and C. albicans in the saliva of children with ECC.Results L. plantarum CCFM8724 significantly reduced the amounts of S. mutans and C. albicans in saliva of children with ECC (p < 0.01). After consumption of L. plantarum CCFM8724, the abundance of Firmicutes, Granulicatella and Gemella increased, whereas the abundance of Proteobacteria, Neisseria, Bifidobacterium and Catonella decreased. Conclusion: Our results emphasize that probiotics could play a beneficial role in the prevention and treatment of ECC in children from an oral microecological perspective.

A Bibliometric Analysis on the Research Trend of Exercise and the Gut Microbiome

This article aims to provide an overview of research hotspots and trends in exercise and the gut microbiome, a field which has recently gained increasing attention. The relevant publications on exercise and the gut microbiome were identified from the Web of Science Core Collection database. The publication types were limited to articles and reviews. VOSviewer 1.6.18 (Centre for Science and Technology Studies, Leiden University, Leiden, the Netherlands) and the R package "bibliometrix" (R Foundation: Vienna, Austria) were used to conduct a bibliometric analysis. A total of 327 eligible publications were eventually identified, including 245 original articles and 82 reviews. A time trend analysis showed that the number of publications rapidly increased after 2014. The leading countries/regions in this field were the USA, China, and Europe. Most of the active institutions were from Europe and the USA. Keyword analysis showed that the relationship between disease, the gut microbiome, and exercise occurs throughout the development of this field of research. The interactions between the gut microbiota, exercise, status of the host's internal environment, and probiotics, are important facets as well. The research topic evolution presents a trend of multidisciplinary and multi-perspective comprehensive analysis. Exercise might become an effective intervention for disease treatment by regulating the gut microbiome. The innovation of exercise-centered lifestyle intervention therapy may become a significant trend in the future.

Next-generation sequencing of the athletic gut microbiota: a systematic review

Aim: There is growing evidence that physical activity modulates gut microbiota composition through complex interactions between diet and microbial species. On the other hand, next-generation sequencing techniques include shotgun metagenomics and 16S amplicon sequencing. These methodologies allow a comprehensive characterisation of microbial communities of athletes from different disciplines as well as non-professional players and sedentary adults exposed to training. This systematic review summarises recent applications of next-generation sequencing to characterise the athletic gut microbiome. Methods: A systematic review of microbiome research was performed to determine the association of microbiota composition profiles with sports performance. Results: Bibliographic analysis revealed the importance of a novel research trend aiming at deciphering the associations between individual microbial species and sports performance. In addition, literature review highlighted the role of butyrate-producing bacteria such as Anaerostipes hadrus, Clostridium bolteae, Faecalibacterium prausnitzii, Roseburia hominis and unidentified species belonging to Clostridiales, Lachnospiraceae and Subdoligranulum species in gut health and sports performance across several disciplines. Interestingly, metabolic activities of Prevotella copri and Veillonella atypica involved in branched amino acid and lactate metabolism may contribute to reducing muscular fatigue. Other microbial metabolic pathways of interest involved in carbohydrate metabolism showed increased proportions in athletes´ metagenomes. Conclusion: Future research will aim at developing personalised nutrition interventions to modulate key species associated with certain components of exercise.

Expanded catalogue of metagenome-assembled genomes reveals resistome characteristics and athletic performance-associated microbes in horse

BACKGROUND

As a domesticated species vital to humans, horses are raised worldwide as a source of mechanical energy for sports, leisure, food production, and transportation. The gut microbiota plays an important role in the health, diseases, athletic performance, and behaviour of horses.

RESULTS

Here, using approximately 2.2 Tb of metagenomic sequencing data from gut samples from 242 horses, including 110 samples from the caecum and 132 samples from the rectum (faeces), we assembled 4142 microbial metagenome-assembled genomes (MAG), 4015 (96.93%) of which appear to correspond to new species. From long-read data, we successfully assembled 13 circular whole-chromosome bacterial genomes representing novel species. The MAG contained over 313,568 predicted carbohydrate-active enzymes (CAZy), over 59.77% of which had low similarity match in CAZy public databases. High abundance and diversity of antibiotic resistance genes (ARG) were identified in the MAG, likely showing the wide use of antibiotics in the management of horse. The abundances of at least 36 MAG (e.g. MAG belonging to Lachnospiraceae, Oscillospiraceae, and Ruminococcus) were higher in racehorses than in nonracehorses. These MAG enriched in racehorses contained every gene in a major pathway for producing acetate and butyrate by fibre fermentation, presenting potential for greater amount of short-chain fatty acids available to fuel athletic performance.

CONCLUSION

Overall, we assembled 4142 MAG from short- and long-read sequence data in the horse gut. Our dataset represents an exhaustive microbial genome catalogue for the horse gut microbiome and provides a valuable resource for discovery of performance-enhancing microbes and studies of horse gut microbiome. Video Abstract.

Structural and functional dysbiosis of gut microbiota in Tibetan subjects with coronary heart disease

The gut microbiota plays a crucial role in coronary heart disease (CHD). However, only a few studies focusing on the relationship between gut microbiota and CHD in ethnic populations are available. Here, we employed shotgun sequencing of the gut metagenome to analyze the taxonomic composition and functional annotation of the gut microbiota of 14 CHD patients, 13 patients with non-stenosis coronary heart disease (NCHD), and 18 healthy controls (HT) in Tibetan subjects. We found that the α-diversity of the gut microbiota was not significantly different among the three groups., whereas β-diversity was significantly altered in the CHD group compared with HT. Based on the receiver operating characteristic curve (ROC) analysis, the relative abundance of Proteobacteria species effectively distinguished patients with CHD from the control group. Most of the enriched species belonged to Proteobacteria. The pathways that contributed the most to the differences between groups were amino acid metabolism-related pathways, especially lysine biosynthesis. The enzymes of the lysine biosynthesis pathway, including K01714 and K00821, were significantly decreased in the CHD group. Our findings increase the understanding of the association between CHD pathogenesis and gut microbiota in the Tibetan population, thus paving the way for the development of improved diagnostic methods and treatments for Tibetan patients with CHD.

Microbial Dark Matter: from Discovery to Applications

With the rapid increase of the microbiome samples and sequencing data, more and more knowledge about microbial communities has been gained. However, there is still much more to learn about microbial communities, including billions of novel species and genes, as well as countless spatiotemporal dynamic patterns within the microbial communities, which together form the microbial dark matter. In this work, we summarized the dark matter in microbiome research and reviewed current data mining methods, especially artificial intelligence (AI) methods, for different types of knowledge discovery from microbial dark matter. We also provided case studies on using AI methods for microbiome data mining and knowledge discovery. In summary, we view microbial dark matter not as a problem to be solved but as an opportunity for AI methods to explore, with the goal of advancing our understanding of microbial communities, as well as developing better solutions to global concerns about human health and the environment.

High fat diet-induced hyperlipidemia and tissue steatosis in rabbits through modulating ileal microbiota

High-fat diet (HFD) and overnutrition are important starting factors that may alter intestinal microbiota, lipid metabolism, and systemic inflammation. However, there were few studies on how intestinal microbiota contributes to tissue steatosis and hyperlipidemia. Here, we investigated the effect of lipid metabolism disorder-induced inflammation via toll-like receptor 2 (TLR-2), toll-like receptor 4 (TLR-4), and nuclear factor-κB (NF-κB) pathways at the intestinal level in response to HFD. Twenty 80-day-old male New Zealand White rabbits were randomly divided into the normal diet group (NDG) and the high-fat diet group (HDG) for 80 days. Growth performance, blood biochemical parameters, lipid metabolism, inflammation, degree of tissue steatosis, and intestinal microbial composition were measured. HFD increased the relative abundance of Christensenellaceae_R_7_group, Marvinbryantia, Akkermansia etc., with a reduced relative abundance of Enterorhabdus and Lactobacillus. Moreover, HFD caused steatosis in the liver and abdominal fat and abnormal expression of some genes related to lipid metabolism and tight junction proteins. The TLR-2, TLR-4, NF-κB, TNF-α, and IL-6 were confirmed by overexpression with downregulation of IL-10. Serum biochemical indices (TG, TCHO, LDL-C, and HDL-C) were also increased, indicating evidence for the development of the hyperlipidemia model. Correlation analysis showed that this microbial dysbiosis was correlated with lipid metabolism and inflammation, which were associated with the intestinal tract's barrier function and hyperlipidemia. These results provide an insight into the relationship between HFD, the intestinal microbiota, intestinal barrier, tissue inflammation, lipid metabolism, and hyperlipidemia. KEY POINTS: • High-fat diet leads to ileal microbiota disorders • Ileal microbiota mediates local and systemic lipid metabolism disorders and inflammation • There is a specific link between ileal microbiota, histopathology, and hyperlipidemia.

Swimming and the human microbiome at the intersection of sports, clinical, and environmental sciences: A scoping review of the literature

The human microbiota is comprised of more than 10-100 trillion microbial taxa and symbiotic cells. Two major human sites that are host to microbial communities are the gut and the skin. Physical exercise has favorable effects on the structure of human microbiota and metabolite production in sedentary subjects. Recently, the concept of "athletic microbiome" has been introduced. To the best of our knowledge, there exists no review specifically addressing the potential role of microbiomics for swimmers, since each sports discipline requires a specific set of techniques, training protocols, and interactions with the athletic infrastructure/facility. Therefore, to fill in this gap, the present scoping review was undertaken. Four studies were included, three focusing on the gut microbiome, and one addressing the skin microbiome. It was found that several exercise-related variables, such as training volume/intensity, impact the athlete's microbiome, and specifically the non-core/peripheral microbiome, in terms of its architecture/composition, richness, and diversity. Swimming-related power-/sprint- and endurance-oriented activities, acute bouts and chronic exercise, anaerobic/aerobic energy systems have a differential impact on the athlete's microbiome. Therefore, their microbiome can be utilized for different purposes, including talent identification, monitoring the effects of training methodologies, and devising ad hoc conditioning protocols, including dietary supplementation. Microbiomics can be exploited also for clinical purposes, assessing the effects of exposure to swimming pools and developing potential pharmacological strategies to counteract the insurgence of skin infections/inflammation, including acne. In conclusion, microbiomics appears to be a promising tool, even though current research is still limited, warranting, as such, further studies.

Microbiota in sports

The influence of microbiota on the human body is currently the subject of many studies. The composition of bacteria colonizing the gastrointestinal tract varies depending on genetic make-up, lifestyle, use of antibiotics or the presence of diseases. The diet is also important in the species diversity of the microbiota. This study is an analysis of the relationships between physical activity, diet, and the microbiota of the gastrointestinal tract in athletes. This review shows the differences in the microbial composition in various sports disciplines, the influence of probiotics on the microbiome, the consequence of which may be achieved even better sports results. Physical activity increases the number of bacteria, mainly of the Clostridiales order and the genus: Lactobacillus, Prevotella, Bacteroides, and Veillonella, and their number varies depending on the sports discipline. These bacteria are present in athletes in sports that require a high VO₂ max. The players’ diet also influences the composition of the microbiota. A diet rich in dietary fiber increases the amount of Lactobacillus or Bifidobacterium bacteria, probiotic microorganisms, which indicates the need to supplement the diet with probiotic preparations. It is impossible to suggest an unambiguous answer to how the microbiota of the gastrointestinal tract changes in athletes and requires further analyzes.

Physical activity induced alterations of gut microbiota in humans: a systematic review

Background

Gut microbiota is considered to have a great impact on human health and disease. While it is widely recognized that the gut microbiota of healthy individuals differs from those with obesity, inflammatory bowel disease, metabolic syndrome, and other chronic diseases, the alterations of gut microbiota with physical activity are not fully understood. Accordingly, we performed this systematic review to address the question regarding the effects of mild and intense exercise on the gut microbiota in humans.

Methods

The comparative analyses of gut microbiota were conducted following the PRISMA protocol to determine the differences in the active vs. non-active individuals (phenotypes) (n = 11), including the influence of physical activity intervention on the human gut microbiota (n = 13); the differences in the gut microbiota of athletes vs. non-athletes (n = 8); and the microbiota status at different stages of athletic performance or intervention (n = 7), with various of physical activities, sport disciplines, and activity duration. Literature searches were completed using four databases: PubMed, Web of Science, Scopus, and EBSCO, and 2090 articles were retrieved by using appropriate keywords. The low heterogeneity of the studies hasn’t allowed us to prepare a meta-analysis. After excluding 2052 articles, we ultimately selected 38 articles that met the eligibility criteria for this review.

Results

The data analyses revealed that in non-athletes rising physical activity markedly influenced the relative abundance of short-chain fatty acid (SCFA). Aerobic training that lasted 60 min, and physical activity that characterized 60% HRmax or more also influenced beta diversity indexes. The results showed that athletes harbor a more diverse type of intestinal microflora than non-athletes, but with a relatively reduced abundance of SCFA- and lactic acid-producing bacteria, thereby suggesting an adverse effect of intense exercise on the population of gut microbiota.

Conclusion

It is concluded that the level of physical activity modulates the gastrointestinal microbiota in humans. For a long period, increasing the intensity and volume of exercise may lead to gut dysbiosis. Perhaps, proper supplementation should be considered to keep gut microbiota in large biodiversity and richness, especially under unfavorable gut conditions associated with intense exercise.

Trial registration

Prospero CRD42021264064.

The Influence of Dietary Factors on the Gut Microbiota

There is increasing evidence that diet influences the relationship between gut microbiota and individual health outcomes. Nutrient intake affects the composition of the gut microbial community and provides metabolites that influence the host physiology. Dietary patterns, including macronutrient balance and feeding/fasting cycles which may be manipulated with dietary regimens based on caloric restriction periods, influence the gut homeostasis through its impact on the microbial ecosystem. Along the same line, prebiotic and probiotic ingredients and additives in foods, as well as the degree of food processing have consequences on gut microbiota and the related immune and metabolic response of the human host. Acquiring knowledge of these aspects, especially through an -omics-integral approach, might provide the basis for personalized nutritional interventions directed to avoid dysbiosis and contribute to the prevention of major chronic degenerative diseases. Despite vast scientific evidence supporting the relationship between dietary factors and gut microbiota composition and function, the underlying mechanisms and their potential impact are far from clear. There is a lack of well-designed longitudinal studies performed in target population groups whose dietary patterns can be particularly relevant for their future health, as is the case in infants, pregnant women, or athletes.

Fecal microbiota monitoring in elite soccer players along the 2019-2020 competitive season

Physical exercise affects the human gut microbiota that, in turn, influences athletes' performance. The current understanding of how the microbiota of professional athletes changes along with different phases of training is sparse. We aim to characterize the fecal microbiota in elite soccer players along with different phases of a competitive season using 16S rRNA gene sequencing. Fecal samples were collected after the summer off-season period, the pre-season retreat, the first half of the competitive season, and the 8 weeks COVID-19 lockdown that interrupted the season 2019-2020. According to our results, the gut microbiota of professional athletes changes along with the phases of the season, characterized by different training, diet, nutritional surveillance, and environment sharing. Pre-season retreat, during which nutritional surveillance and exercise intensity were at their peak, caused a decrease in bacterial groups related to unhealthy lifestyle and an increase in health-promoting symbionts. The competitive season and forced interruption affected other features of the athletes' microbiota, i.e. bacterial groups that respond to dietary fibers load and stress levels. Our longitudinal study, focusing on one of the most followed sports worldwide, provides baseline data for future comparisons and microbiome-targeting interventions aimed at developing personalized training and nutrition plans for performances maximization.

Multi-Omics Analyses Characterize the Gut Microbiome and Metabolome Signatures of Soldiers Under Sustained Military Training

Exercise can directly alter the gut microbiome at the compositional and functional metabolic levels, which in turn may beneficially influence physical performance. However, data how the gut microbiome and fecal metabolome change, and how they interact in soldiers who commonly undergo sustained military training are limited. To address this issue, we first performed 16S rRNA sequencing to assess the gut microbial community patterns in a cohort of 80 soldiers separated into elite soldiers (ES, n = 40) and non-elite soldiers (N-ES, n = 40). We observed that the α-diversities of the ES group were higher than those of the N-ES group. As for both taxonomical structure and phenotypic compositions, elite soldiers were mainly characterized by an increased abundance of bacteria producing short-chain fatty acids (SCFAs), including Ruminococcaceae_UCG-005, Prevotella_9, and Veillonella, as well as a higher proportion of oxidative stress tolerant microbiota. The taxonomical signatures of the gut microbiome were significantly correlated with soldier performance. To further investigate the metabolic activities of the gut microbiome, using an untargeted metabolomic method, we found that the ES and N-ES groups displayed significantly different metabolic profiles and differential metabolites were primarily involved in the metabolic network of carbohydrates, energy, and amino acids, which might contribute to an enhanced exercise phenotype. Furthermore, these differences in metabolites were strongly correlated with the altered abundance of specific microbes. Finally, by integrating multi-omics data, we identified a shortlist of bacteria-metabolites associated with physical performance, following which a random forest classifier was established based on the combinatorial biomarkers capable of distinguishing between elite and non-elite soldiers with high accuracy. Our findings suggest possible future modalities for improving physical performance through targeting specific bacteria associated with more energetically efficient metabolic patterns.

The Potential of Gut Microbiota Metabolic Capability to Detect Drug Response in Rheumatoid Arthritis Patients

Gut microbiota plays an essential role in the development of rheumatoid arthritis (RA) and affects drug responses. However, the underlying mechanism remains elusive and urgent to elucidate to explore the pathology and clinical treatment of RA. Therefore, we selected methotrexate (MTX) as an example of RA drugs to explore the interactions between the gut microbiota and drug responses and obtain an in-depth understanding of their correlation from the perspective of the metabolic capability of gut microbiota on drug metabolism. We identified 2,654 proteins and the corresponding genes involved in MTX metabolism and then profiled their abundances in the gut microbiome datasets of four cohorts. We found that the gut microbiota harbored various genes involved in MTX metabolism in healthy individuals and RA patients. Interestingly, the number of genes involved in MTX metabolism was not significantly different between response (R) and non-response (NR) groups to MTX, but the gene composition in the microbial communities significantly differed between these two groups. Particularly, several models were built based on clinical information, as well as data on the gene, taxonomical, and functional biomarkers by using the random forest algorithm and then validated. Our findings provide bases for clinical management not only of RA but also other gut microbiome–related diseases. First, it suggests that the potential metabolic capability of gut microbiota on drug metabolism is important because they affect drug efficiency; as such, clinical treatment strategies should incorporate the gene compositions of gut microbial communities, in particular genes involved in drug metabolism. Second, a suitable model can be developed to determine hosts’ responses to drugs before clinical treatment.

Gut Bacterial Composition and Functional Potential of Tibetan Pigs Under Semi-Grazing

Gut bacterial community plays a key role in maintaining host health. The Tibetan pig (Sus scrofa), an ancient breed in China, has been known for its high adaptability to harsh environments and for its meat quality. To understand the underlying mechanisms facilitating to shape these unique features, in this study, 16S rRNA sequencing using pigs feces and subsequent bacterial functional prediction were performed. Also, the gut bacteria of two other breeds of pigs, Barkshire and Landrace, were examined for comparison. It was revealed that the structure of bacterial community in Tibetan pigs appeared to be more complex; the relative abundances of dominant bacterial families varied inversely with those of the other pigs, and the proportion of Firmicutes in Tibetan pigs was lower, but Bacteroides, Fibrobacterota, Lachnospiraceae, Oscillospiraceae, and Ruminococcaceae were higher. Bacterial functional prediction revealed that the dominant flora in the Tibetan pigs was more correlated with functions regulating the hosts’ immune and inflammatory responses, such as NOD-like_receptor_signaling_pathway and vitamin metabolism. In addition, in Tibetan pigs, the taxonomic relationships in the gut bacteria on day 350 were closer than those on earlier stages. Furthermore, gender played a role in the composition and function of bacterial inhabitants in the gut; for boars, they were more correlated to drug resistance and xenobiotics metabolism of the host compared to the sows. In sum, our preliminary study on the gut bacterial composition of the Tibetan pigs provided an insight into the underlying host–microorganism interactions, emphasizing the role of intestinal bacteria in the context of modulating the host’s immune system and host development.

Gut microbiota of elite female football players is not altered during an official international tournament

The current study aimed to investigate if the gut microbiota composition of elite female football players changes during an official international tournament. The study was conducted throughout ten consecutive days, encompassing seven training sessions, and three official matches. The matches were separated by 48-72 h. Seventeen elite female football players from the Portuguese women's national football team participated in the study. Fecal samples were collected at two time points: at the beginning and end of the tournament. Fecal microbiota was analyzed by sequencing the 16S rRNA gene. Throughout the study, the duration and rating of perceived exertion (RPE) were recorded after training sessions and matches. The internal load was determined by the session RPE. The gut microbiota of players was predominantly composed of bacteria from the phyla Firmicutes (50% of relative abundance) and Bacteroidetes (20%); the genera Faecalibacterium (29%) and Collinsella (16%); the species Faecalibacterium prausnitzii (30%) and Collinsella aerofaciens (17%). Overall, no significant changes were observed between time points (p ≥ 0.05). Also, no relationship was found between any exercise parameter and the gut microbiota composition (p ≥ 0.05). These findings demonstrate that the physical and physiological demands of training and matches of an official international tournament did not change the gut microbiota composition of elite female football players. Furthermore, it supports that the gut microbiota of athletes appears resilient to the physical and physiological demands of training and match play.

Disparity of Gut Microbiota Composition Among Elite Athletes and Young Adults With Different Physical Activity Independent of Dietary Status: A Matching Study

Objective

This study aimed to investigate the disparity of gut microbiota among elite athletes and young adults with different physical activity independent of dietary status.

Methods

In Hangzhou, China, an age and sex matching study was conducted between April and May 2021. A total of 66 Chinese young adults were recruited in this study and divided into an elite athlete group, physically active group, and physically inactive group. Fecal samples were collected to assess gut microbiota composition. Dietary status was measured using a food-frequency questionnaire. Comparisons in gut microbiota and blood biomarkers among three groups were analyzed by using the analysis of covariance.

Results

The findings depicted a tendency to form clusters for beta diversity among three groups, while no significant difference was observed in both alpha and beta diversity. In the multiple analysis model, by adjusting dietary status, a significantly higher abundance of Clostridiaceae (p = 0.029) and Megamonas_rupellensis (p = 0.087) was observed in elite athletes compared to that in general young adults. Furthermore, inflammation-related bacteria such as Bilophila (p = 0.011) and Faecalicoccus (p = 0.050) were enriched in physically inactive young adults compared to two other groups. Pearson's correlation analysis showed a positive association between Bilophila and circulating white body cell count (r = 0.332, p = 0.006) and its subtypes including neutrophils (r = 0.273, p = 0.027), and lymphocytes (r = 0.327, p = 0.007). Megamonas_rupellensis has been shown associated positively with serum lymphocytes levels (r = 0.268, p = 0.03). Although no significant differences were observed, the elite athletes tended to have lower levels of blood biomarkers of immunity within a normal range, which may reflect a better immune function.

Conclusion

This matching study indicated that physically inactive young adults are more likely to have a lower immune function and a higher abundance of pro-inflammatory gut bacteria than elite athletes and physically active young adults. Dietary status should be considered as an important factor that may affect the association of physical activity with immune function and gut microbiota.

Alterations to the gut microbiome after sport-related concussion in a collegiate football players cohort: A pilot study

Concussions, both single and repetitive, cause brain and body alterations in athletes during contact sports. The role of the brain-gut connection and changes in the microbiota have not been well established after sports-related concussions or repetitive subconcussive impacts. We recruited 33 Division I Collegiate football players and collected blood, stool, and saliva samples at three time points throughout the athletic season: mid-season, following the last competitive game (post-season), and after a resting period in the off-season. Additional samples were collected from four athletes that suffered from a concussion. 16S rRNA sequencing of the gut microbiome revealed a decrease in abundance for two bacterial species, Eubacterium rectale, and Anaerostipes hadrus, after a diagnosed concussion. No significant differences were found regarding the salivary microbiome. Serum biomarker analysis shows an increase in GFAP blood levels in athletes during the competitive season. Additionally, S100β and SAA blood levels were positively correlated with the abundance of Eubacterium rectale species among the group of athletes that did not suffer a diagnosed concussion during the sports season. These findings provide initial evidence that detecting changes in the gut microbiome may help to improve concussion diagnosis following head injury.

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A longitudinal study following college football athletes across a sports season.

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Nanopore 16S rRNA sequencing of gut microbiome reveals changes after head injury.

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Serum biomarker GFAP increased during the competitive period of the season.

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S100β and SAA blood levels were positively correlated with Eubacterium rectale.

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Gut microbiota is suggested as a future biomarker for diagnosis following head injury.

A proposal for the reference intervals of the Italian microbiota "scaffold" in healthy adults

Numerous factors, ranging from genetics, age, lifestyle, and dietary habits to local environments, contribute to the heterogeneity of the microbiota in humans. Understanding the variability of a “healthy microbiota” is a major challenge in scientific research. The gut microbiota profiles of 148 healthy Italian volunteers were examined by 16S rRNA gene sequencing to determine the range and diversity of taxonomic compositions in the gut microbiota of healthy populations. Possible driving factors were evaluated through a detailed anamnestic questionnaire. Microbiota reference intervals were also calculated. A “scaffold” of a healthy Italian gut microbiota composition was identified. Differences in relative quantitative ratios of microbiota composition were detected in two clusters: a bigger cluster (C₂), which included 124 subjects, was characterized by more people from the northern Italian regions, who habitually practised more physical activity and with fewer dietary restrictions. Species richness and diversity were significantly higher in this cluster (C₂) than in the other one (C₁) (C₁: 146.67 ± 43.67; C₂: 198.17 ± 48.47; F = 23.40; P < 0.001 and C₁: 16.88 ± 8.66; C₂: 35.01 ± 13.40; F = 40.50; P < 0.001, respectively). The main contribution of the present study was the identification of the existence of a primary healthy microbiological framework that is only marginally affected by variations. Taken together, our data help to contextualize studies on population-specific variations, including marginal aspects, in human microbiota composition. Such variations must be related to the primary framework of a healthy microbiota and providing this perspective could help scientists to better design experimental plans and develop strategies for precision tailored microbiota modulation.

Nine weeks of high-intensity indoor cycling training induced changes in the microbiota composition in non-athlete healthy male college students

Background

The gut microbiota constitutes a dynamic microbial system constantly challenged by environmental conditions, including physical exercise. Limited human studies suggest that exercise could play a beneficial role for gut health, increasing microbial diversity, even if the effects of exercise on gut microbial microorganisms depends on its intensity and duration. This study aimed to investigate the effects of nine weeks of high-intensity interval exercise on gut microbiota composition in healthy young adults.

Methods

The gut microbiota composition of seventeen healthy male college students was analysed before and after nine weeks of high-intensity interval cycling training by 16S rRNA amplicon sequencing. PERMANOVA for repeated measures was used to test pre-post differences in the relative abundance of all taxonomic levels, and correlations between variations in microbial composition and physical and dietary features were also assessed.

Results

Physical exercise induced changes in microbiota composition, at all taxonomic levels analysed (phyla: F _{[1, 32]}=3.97, p=0.029; classes: F _{[1, 32]}=3.39, p=0.033, orders: F _{[1, 32]}=3.17, p=0.044, families: F _{[1, 32]}=1.54, p=0.037, genera: F _{[1, 32]}=1.46, p=0.015, species: F _{[1, 32]}=1.38, p=0.007). Conversely, no differences were found between pre and post-training conditions for microbial community richness (Chao1: V=105, p=0.06) or diversity (Shannon index: V=62, p=0.52; Simpson index: V=59, p=0.43). Changes in the relative abundance of eighteen genera were correlated to changes of twenty environmental factors grouped in physical features, sport-related features, and dietary features.

Conclusions

Nine weeks of high-intensity exercise induced modifications in gut microbiota composition in healthy male college students, shifting the gut microbial population towards a healthier microbiome with benefit to human health in general.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12970-021-00471-z.

The Native Dietary Habits of the Two Sympatric Bee Species and Their Effects on Shaping Midgut Microorganisms

The intestinal microbial community composition of different bee species typically has host specificity, yet little is known about the underlying formation mechanism. There are signs that dietary habits vary in different bee species, suggesting that there may be close relationships between dietary habits and intestinal microorganisms. We explored this hypothesis by comparing the dietary habits and gut microbiota of two common bee species (Apis mellifera L. and Apis cerana cerana) in China. Bee bread and midgut samples from wild and laboratory-reared bees were collected, and the differences in intestinal microbial community composition and growth and development before and after the change in dietary habits of different bee species were compared. We found that the two sympatric species had different dietary specializations and similar metagenomic diversities. The microbiota composition differed between the two species. Moreover, we revealed that changes in native dietary habits destroyed the intestinal microbiota community composition, negatively affecting the growth and development of honeybees.

Can Physical Activity Influence Human Gut Microbiota Composition Independently of Diet? A Systematic Review

Evidence suggests that physical activity (PA) influences the human gut microbiota composition, but its role is unclear because of dietary interference. The aim of this review is to clarify this issue from this new perspective in healthy individuals. Articles analyzing intestinal microbiota from fecal samples by 16S rRNA amplicon sequencing were selected by searching the electronic databases PubMed, Scopus, and Web of Science until December 2020. For each study, methodological quality was assessed, and results about microbiota biodiversity indices, phylum and genus composition, and information on PA and diet were considered. From 997 potentially relevant articles, 10 met the inclusion criteria and were analyzed. Five studies involved athletes, three were performed on active people classified on the basis of habitual PA level, and two among sedentary subjects undergoing exercise interventions. The majority of the studies reported higher variability and prevalence of the phylum Firmicutes (genera Ruminococcaceae or Fecalibacteria) in active compared to inactive individuals, especially in athletes. The assessment of diet as a possible confounder of PA/exercise effects was completed only in four studies. They reported a similar abundance of Lachnospiraceae, Paraprevotellaceae, Ruminococcaceae, and Veillonellaceae, which are involved in metabolic, protective, structural, and histological functions. Further studies are needed to confirm these findings.

Impacts of Maternal Diet and Alcohol Consumption during Pregnancy on Maternal and Infant Gut Microbiota

(1) Background: Maternal diet and alcohol consumption can influence both maternal and infant's gut microbiota. These relationships are still not examined in the Chinese population. The purpose of this study was to explore the effect of alcohol consumption and maternal diet during pregnancy on maternal and infant's gut microbiota. (2) Methods: Twenty-nine mother-child dyads were enrolled in central China. Fecal samples of mothers during late pregnancy and of newborns within 48 h were collected. The V3-V4 regions of 16S rRNA sequences were analyzed. A self-administrated questionnaire about simple diet frequency in the past week was completed by mothers before childbirth. The demographic information was finished by mothers at 24 h after childbirth. (3) Results: Among these 29 mothers, 10 mothers reported alcohol consumption during pregnancy. The PCoA (β-diversity) showed significant difference in maternal gut microbiota between the alcohol consumption group vs. the non-alcohol consumption group (abund-Jaccard, r = 0.2, p = 0.006). The same phenomenon was observed in newborns (unweighted-UniFrac full tree, r = 0.174, p = 0.031). Maternal alcohol consumption frequency showed positive associations with maternal Phascolarctobacterium (p = 0.032) and Blautia (p = 0.019); maternal Faecalibacterium (p = 0.013) was negatively correlated with frequency of alcohol consumption. As for newborns, a positive relationship showed between Megamonas (p = 0.035) and newborns with maternal alcohol consumption. The diet was not associated with both maternal and infant's gut microbiota. (4) Conclusions: Maternal alcohol consumption during pregnancy influenced the gut microbiota on both mothers and the newborns. Future research is needed to explore these relationships in a lager birth cohort. Understanding the long-term effect of alcohol consumption on maternal and newborns' gut microbiota is needed.