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(A) Overview of study design. Following randomization, participants received 4 weeks of daily probiotic or placebo supplementation. Drug administration was followed by a 4 week washout period prior to the crossover assessment period. GI permeability, body composition, blood chemistry, and fecal microbiota were assessed before and after each 4‐week intervention period. (B) CONSORT flow diagram. Nine participants were randomized to placebo (N = 4) or UCC118 (N = 5). Two participants, one from each treatment arm, were lost to follow‐up during the 28‐day washout period. All seven of the completed subjects were included in the analysis of primary and secondary study outcomes.
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Dysregulation of gut microbiota and intestinal barrier function has emerged as potential mechanisms underlying digestive diseases, yet targeted therapies are lacking The purpose of this investigation was to assess the efficacy of UCC118, a characterized probiotic strain, on exercise-induced GI permeability in healthy humans. In a randomized, double...
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Citations
... Recently, a cross-sectional study involving male long-distance runners showed a positive correlation between Bacteroides uniformis abundance and enhanced performance in endurance exercise (Morita et al. 2023). All these studies open new applications for probiotics, prebiotics, and symbiotic combinations, focused on improving physical activity through a variety of food supplements (Axelrod et al. 2019, Marttinen et al. 2020. ...
Many physical, social, and psychological changes occur during aging that raise the risk of developing chronic diseases, frailty, and dependency. These changes adversely affect the gut microbiota, a phenomenon known as microbe-aging. Those microbiota alterations are, in turn, associated with the development of age-related diseases. The gut microbiota is highly responsive to lifestyle and dietary changes, displaying a flexibility that also provides anactionable tool by which healthy aging can be promoted. This review covers, firstly, the main lifestyle and socioeconomic factors that modify the gut microbiota composition and function during healthy or unhealthy aging and, secondly, the advances being made in defining and promoting healthy aging, including microbiome-informed artificial intelligence tools, personalized dietary patterns, and food probiotic systems.
... The participants in this study were asked to provide subjective ratings of their GI symptoms and functions, a crucial aspect of our protocol given the focus on probiotic supplementation. As observed in Table 3, our results for these outcomes (as measured in the GSRS) aligned with other running studies in master athletes, finding a potential benefit of the use of probiotics in athletes for improving gut health [17,22,43,44]. Notably, as detailed in Table 4, KFR supplementation, in comparison to PLA, resulted in a significantly lower total GSRS score following the exhaustive-exercise bout, illustrating the potential of KFR in mitigating GI symptoms. ...
This study compared flavored kefir (KFR) and flavored milk (MLK) as a recovery drink in endurance master athletes. Using a randomized, placebo-controlled, non-blinded crossover design, 11 males and females completed three testing visits whilst acutely ingesting either KFR, MLK, or water as a placebo (PLA). KFR supplementation occurred for 14 days before the KFR-testing day, followed by a 3-week washout period. Testing visits consisted of an exhausting-exercise (EE) bout, a 4-h rest period where additional carbohydrate feeding was provided, and a treadmill 5 km time trial (TT). The Gastrointestinal Symptom Rating Scale (GSRS) survey was assessed at four timepoints. Blood was collected at baseline and after the TT and was analyzed for I-FABP levels. No significant difference (PLA: 33:39.1 ± 6:29.0 min, KFR: 33:41.1 ± 5:44.4 min, and MLK: 33:36.2 ± 6:40.5 min, p = 0.99) was found between the groups in TT performance. The KFR GSRS total score was significantly lower than the PLA after EE (p = 0.005). No differences in I-FABP were observed between conditions. In conclusion, acute KFR supplementation did not impact TT performance or I-FABP levels but may have reduced subjective GI symptoms surrounding exercise when compared to MLK or PLA.
... Axelrod et al. assessed the efficacy of a probiotic strain, namely UCC118, on exercise-induced GI permeability in healthy humans. Seven healthy adults received 4 weeks of daily UCC118 or placebo supplementation, and GI hyperpermeability was induced by strenuous running performed before and after each supplementation period [64]. The authors showed that 4 weeks of UCC118 supplementation attenuated exercise-induced intestinal hyperpermeability, and a significant reduction in the phylum Verrucomicrobia (q < 0.001) was detected [64]. ...
... Seven healthy adults received 4 weeks of daily UCC118 or placebo supplementation, and GI hyperpermeability was induced by strenuous running performed before and after each supplementation period [64]. The authors showed that 4 weeks of UCC118 supplementation attenuated exercise-induced intestinal hyperpermeability, and a significant reduction in the phylum Verrucomicrobia (q < 0.001) was detected [64]. ...
Strenuous exercise can be associated with “Exercise Induced Gastrointestinal Syndrome” (Ex-GIS), a clinical condition characterized by a series of gastrointestinal (GI) disturbances that may impact the physical and psychological performance of athletes. The pathophysiology comprises multi-factorial interactions between the GI tract and the circulatory, immune, enteric, and central nervous systems. There is considerable evidence for increases in the indices of intestinal damage, permeability, and endotoxemia associated with impaired gastric emptying, slowing of small intestinal transit, and malabsorption of nutrients. Heat stress and racing mode seem to exacerbate these GI disturbances. GI symptomatology that derives from strenuous exercise is similar to that of IBS and other GI functional disorders defined in the Rome IV Criteria. To manage Ex-GIS, the exercise modality, state of dehydration, environmental temperature, concomitant therapies, and self-managed diet should be evaluated, and if risk elements are present, an attempt should be made to modify them. Multiple strategies can be successively adopted to manage Ex-GIS. Nutritional and behavioral interventions appear to be the principal ones to avoid symptoms during the exercise. The aim of this review will be to explore the pathophysiology, clinical aspect, and current literature on behavioral and nutritional strategies to manage Ex-GIS, regarding a gluten-free diet and low-fermentable oligo-, di-, and mono-saccharides and polyols (FODMAP) diet.
... No between-group differences or time effects were found regarding anaerobic or aerobic performance. Few studies have investigated the effects of protein supplementation on anaerobic (59) and aerobic performance (61)(62)(63). Regarding protein supplementation on muscle power Camera et al. (59) showed similar results to ours. Also, it seems that when adequate amounts of carbohydrates are consumed, protein supplementation does not further increase aerobic performance (24). ...
... This is the first study to compare a plant-based protein vs. whey in professional and semi-professional team sports athletes (i.e., futsal). Few (or no) studies have compared the effects of a protein source when provided as supplemental protein outside RET or strength/power sports (61)(62)(63), with only one comparative study being performed in collegiate female basketball players (whey vs. casein) (69). Furthermore, we supplemented with an iso-energetic, iso-nitrogenous, iso-EAA novel plant-based protein/BCAA mixture that matched whey protein, using yeast protein for the first time. ...
... Current guidelines suggest that dietary intervention and exercise are first-line therapy for NAFLD (61,62). Correspondingly, the European Association for the Study of the Liver (EASL) guidelines focus on lifestyle changes through diet and habitual physical activity and emphasize that diet-induced weight loss is the only treatment to ameliorate liver damage without severe liver fibrosis (63). Given that these guidelines recommend a pragmatic and individualized approach and do not advocate any specific diet for the treatment of NAFLD, our findings are noteworthy as a means of expanding the effect of IF regimens as one of many dietary strategies that can be employed through a personalized perspective, but this does not imply that IF is the best dietary approach. ...
Nutritional research includes the investigation of various dietary approaches, functional foods, and supplements, to guide personalized advice to enhance health and/or performance (1–8). Evidence-based decisions must be made based on the most recent advances in research. Therefore, we created a special issue entitled “Functional Foods, Supplements, and Dietary Approaches in Sports and Clinical Nutrition”, which consisted of a number of leading experts. In the special issue, 7 papers were focused on health or clinical populations and 4 manuscripts had a sport or performance focus. In this editorial, we briefly highlight the key aspects of each manuscript.
... After title and abstract assessment, 40 articles were considered as potential studies. After full-text review and assessment of potential registries, 13 studies [27][28][29][30][31][32][33][34][35][36][37][38][39] were included in the systematic review ( Figure 1). ...
... Four studies [27,28,30,39] had results ≥ 15 points, corresponding to "excellent" quality, and nine [29,[31][32][33][34][35][36][37][38] studies had results between 13 and 14 points, corresponding to "very good" quality (Table 1). ...
... The total number of physically active adults included in this systematic review was 300 (248 men, 4 women, and 48 unspecified). A total of 269 participants were endurance athletes [22][23][24][25][26][27]29,[31][32][33][34], 27 were elite athletes [39], and 31 participants were strength athletes [33,35]. Six studies used a supplement manufactured for the study [22,25,26,29,30,34], six studies used a proprietary commercial supplement [29,32,33,[36][37][38], and one study did not report [28]. ...
Supplementation with probiotics in sports is on the rise with the aim of improving health and athletic performance. Since intense exercise-induced muscle damage leads to an inflammatory process by increasing circulating inflammatory cytokines, probiotic supplementation may modulate and correct the inflammation. We systematically reviewed the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines in the Scopus, Web of Science, and Med-line databases for the 10 years until January 2023. This review aimed to evaluate probiotic supple-mentation as a strategy for modulating inflammation in healthy physically active adults or athletes. Studies were indexed to assess the effect of probiotic supplementation on cytokine behavior in the inflammatory response in physically active individuals. Of the 136 studies identified in the search, 13 met the inclusion criteria, and their quality was assessed using the McMaster Critical Review Form. The results of these trials indicated a significant improvement in inflammatory cytokines in probiotic-supplemented participants, with a significant increase in anti-inflammatory cytokines (IL-10) and a significant decrease in proinflammatory cytokines (IL-6, TNF-α, and IL-8). This would create uncertainty about probiotics' effect on interleukins' behavior after exercise, and further clinical trials are needed to establish a solid basis.
... Intestinal permeability at rest N = 6 studies assessed markers of intestinal permeability at rest, before and after the supplementation period (Tables 3, 4). Reported markers included urinary lactulose:mannitol ratio (62, 94, 98), fecal (62,63,76) and serum zonulin (62,88). One study observed a reduction in both urinary lactulose:mannitol ratio and serum zonulin, pre-to post-supplement period with inulinenriched pasta ingestion, and no change was observed in the placebo trial (62). ...
... The synbiotic supplements included two to four probiotic strains, plus additional fructooligosaccharides or inulin (94, 96). The acute exercise bouts varied substantially, and included n = 3 studies of treadmill running (either 2 h steady state with or without environmental heat exposure (e.g., 35 • C), or time to exhaustion test) (63, 68, 100); n = 4 studies investigated supplementation prior to an outdoor marathon (65, 79, 87, 89); n = 3 studies on a cycle ergometer (either an incremental exercise test, time to fatigue tests or 2 h steady state cycle ergometer followed by 1 h time trial) (63,90,100); and, in one study participants completed an ultra-distance triathlon event (94). One study observed participant outcomes in response to 5 days of continuous intense military training, day and night including marching 8-30 km whilst carrying a pack up to 30 kg, sleep deprivation, and a range of environmental conditions (96). ...
... None of the studies observed differences between intervention and placebo for urinary lactulose:mannitol or lactulose:rhamnose ratio, indicative of small intestinal permeability. N = 1 study assessed sucrose permeability, indicative of gastroduodenal permeability, at baseline and immediately post-exercise, reporting a 38% significantly lower incremental area under the curve from baseline in the intervention trial, and a 169% increase from baseline in the placebo trial, after 4 weeks Lactobacillus salivarius UCC118 (2 × 10 8 CFU daily) (63). The effect of a synbiotic supplement (four probiotic strains plus fructooligosaccharides) was investigated on urinary lactulose:mannitol ratio, before and 6 days after a long course triathlon event, with no effect of trial observed (94). ...
Introduction
A systematic literature search was undertaken to assess the impact of pre-, pro-, and syn-biotic supplementation on measures of gastrointestinal status at rest and in response to acute exercise.
Methods
Six databases (Ovid MEDLINE, EMBASE, Cinahl, SportsDISCUS, Web of Science, and Scopus) were used. Included were human research studies in healthy sedentary adults, and healthy active adults, involving supplementation and control or placebo groups. Sedentary individuals with non-communicable disease risk or established gastrointestinal inflammatory or functional diseases/disorders were excluded.
Results
A total of n = 1,204 participants were included from n = 37 papers reported resting outcomes, and n = 13 reported exercise-induced gastrointestinal syndrome (EIGS) outcomes. No supplement improved gastrointestinal permeability or gastrointestinal symptoms (GIS), and systemic endotoxemia at rest. Only modest positive changes in inflammatory cytokine profiles were observed in n = 3/15 studies at rest. Prebiotic studies (n = 4/5) reported significantly increased resting fecal Bifidobacteria, but no consistent differences in other microbes. Probiotic studies (n = 4/9) increased the supplemented bacterial species-strain. Only arabinoxylan oligosaccharide supplementation increased total fecal short chain fatty acid (SCFA) and butyrate concentrations. In response to exercise, probiotics did not substantially influence epithelial injury and permeability, systemic endotoxin profile, or GIS. Two studies reported reduced systemic inflammatory cytokine responses to exercise. Probiotic supplementation did not substantially influence GIS during exercise.
Discussion
Synbiotic outcomes resembled probiotics, likely due to the minimal dose of prebiotic included. Methodological issues and high risk of bias were identified in several studies, using the Cochrane Risk of Bias Assessment Tool. A major limitation in the majority of included studies was the lack of a comprehensive approach of well-validated biomarkers specific to gastrointestinal outcomes and many included studies featured small sample sizes. Prebiotic supplementation can influence gut microbial composition and SCFA concentration; whereas probiotics increase the supplemented species-strain, with minimal effect on SCFA, and no effect on any other gastrointestinal status marker at rest. Probiotic and synbiotic supplementation does not substantially reduce epithelial injury and permeability, systemic endotoxin and inflammatory cytokine profiles, or GIS in response to acute exercise.
... Briefly, 35 studies used a parallel group design, 5,7,22,23,[25][26][27][28][29][30][31][32][35][36][37][41][42][43][44][45][46][47][49][50][51][52][53][55][56][57][58][59][60][61][62] whereas 10 used a crossover design. 4,6,24,33,34,[38][39][40]48,54 The studies were conducted in Finland, 22,23,30 Australia, 24,27,32,[34][35][36]49,57 the UK, 5,25,28,38,39,43,54,58 Italy, 26 Austria, 29,42 Iran, 31,37 New Zealand, 33 the USA, 6,40,47,48,56 Serbia, 41,44 Taiwan, 45,53 Malaysia, 46,51,59 Brazil, 50,52,61 Sweden, 7 Poland, 55 India, 62 and Israel. 60 The majority of included RCTs (27 studies in total) used probiotic preparations in their study arms with a single strain from the genera Lactobacillus, 4,7,[22][23][24][25]27,28,30,38,39,41,44,45,48,50,51,59 Bifidobacterium, 32,35,36,53 Bacillus, 47,56,62 or Saccharomyces. ...
... Briefly, 35 studies used a parallel group design, 5,7,22,23,[25][26][27][28][29][30][31][32][35][36][37][41][42][43][44][45][46][47][49][50][51][52][53][55][56][57][58][59][60][61][62] whereas 10 used a crossover design. 4,6,24,33,34,[38][39][40]48,54 The studies were conducted in Finland, 22,23,30 Australia, 24,27,32,[34][35][36]49,57 the UK, 5,25,28,38,39,43,54,58 Italy, 26 Austria, 29,42 Iran, 31,37 New Zealand, 33 the USA, 6,40,47,48,56 Serbia, 41,44 Taiwan, 45,53 Malaysia, 46,51,59 Brazil, 50,52,61 Sweden, 7 Poland, 55 India, 62 and Israel. 60 The majority of included RCTs (27 studies in total) used probiotic preparations in their study arms with a single strain from the genera Lactobacillus, 4,7,[22][23][24][25]27,28,30,38,39,41,44,45,48,50,51,59 Bifidobacterium, 32,35,36,53 Bacillus, 47,56,62 or Saccharomyces. ...
... 4,6,24,33,34,[38][39][40]48,54 The studies were conducted in Finland, 22,23,30 Australia, 24,27,32,[34][35][36]49,57 the UK, 5,25,28,38,39,43,54,58 Italy, 26 Austria, 29,42 Iran, 31,37 New Zealand, 33 the USA, 6,40,47,48,56 Serbia, 41,44 Taiwan, 45,53 Malaysia, 46,51,59 Brazil, 50,52,61 Sweden, 7 Poland, 55 India, 62 and Israel. 60 The majority of included RCTs (27 studies in total) used probiotic preparations in their study arms with a single strain from the genera Lactobacillus, 4,7,[22][23][24][25]27,28,30,38,39,41,44,45,48,50,51,59 Bifidobacterium, 32,35,36,53 Bacillus, 47,56,62 or Saccharomyces. 49,57 A total of 23 studies implemented multi-strain preparations, ranging from 2-8 probiotic strains. ...
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 (RCTs) 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 RCTs 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 7–150 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.
... The urinary excretion ratio (the recovery of the larger probe relative to the smaller) is most often reported and provides a standardized measure of intestinal permeability at the region of the GI tract where the larger probe is absorbed [17]. Due to a supplier error, a monosaccharide probe was not included in the intestinal permeability assessment, but the crossover design of the study still allowed for meaningful within-subjects comparisons for percent recovery of the disaccharide probes, and some other studies have similarly reported percent recovery of disaccharide sugars [3,[65][66][67][68][69][70]. ...
Background
Submaximal endurance exercise has been shown to cause elevated gastrointestinal permeability, injury, and inflammation, which may negatively impact athletic performance and recovery. Preclinical and some clinical studies suggest that flavonoids, a class of plant secondary metabolites, may regulate intestinal permeability and reduce chronic low-grade inflammation. Consequently, the purpose of this study was to determine the effects of supplemental flavonoid intake on intestinal health and cycling performance.
Materials and methods
A randomized, double-blind, placebo-controlled crossover trial was conducted with 12 cyclists (8 males and 4 females). Subjects consumed a dairy milk-based, high or low flavonoid (490 or 5 mg) pre-workout beverage daily for 15 days. At the end of each intervention, a submaximal cycling trial (45 min, 70% VO2max) was conducted in a controlled laboratory setting (23°C), followed by a 15-minute maximal effort time trial during which total work and distance were determined. Plasma samples were collected pre- and post-exercise (0h, 1h, and 4h post-exercise). The primary outcome was intestinal injury, assessed by within-subject comparison of plasma intestinal fatty acid-binding protein. Prior to study start, this trial was registered at ClinicalTrials.gov (NCT03427879).
Results
A significant time effect was observed for intestinal fatty acid binding protein and circulating cytokines (IL-6, IL-10, TNF-α). No differences were observed between the low and high flavonoid treatment for intestinal permeability or injury. The flavonoid treatment tended to increase cycling work output (p = 0.051), though no differences were observed for cadence or total distance.
Discussion
Sub-chronic supplementation with blueberry, cocoa, and green tea in a dairy-based pre-workout beverage did not alleviate exercise-induced intestinal injury during submaximal cycling, as compared to the control beverage (dairy-milk based with low flavonoid content).
... Dışkı homojenatlarının shotgun metagenomik dizilimi, altı taksonomik sınıflandırmayı kapsayan 99 farklı düzenlenmiş mikroorganizmayı ortaya çıkarmıştır. Filum Verrucomicrobia' da ise önemli bir azalma görülmüştür (36). ...
... Beslenme ve probiyotik alımına ilişkin yönergeleri optimize etmek için; egzersiz prosedürlerindeki farklılıklar, beslenme ve kültürel farklılıklar ile bireysel probiyotik kullanım türleri arasındaki farklıklara dayanan deneysel bir tasarımla incelenmesi gerekli olduğu ortaya çıkmıştır (29). Bazı probiyotik takviyelerinin sporcuların bağırsak geçirgenliğini artırdığını, bu durumun probiyotik takviyesinin, sağlıklı yetişkinlerde egzersize bağlı aşırı bağırsak geçirgenliğini azalttığı ilkesini de kanıtlamıştır (36). Probiyotiklerin egzersiz performansını iyileştirme üzerindeki etkisinin, takviye edilen tür, cins, dozaj ve süre ile ilişkili olması muhtemeldir. ...
Gastrointestinal sistemdeki mikroorganizmalar, besin alımı, vitamin sentezi, enerji hasadı, enflamatuar modülasyon ve konakçı bağışıklık tepkisinde önemli bir rol oynar ve toplu olarak insan sağlığına katkıda bulunur. Bağırsak mikrobiyotasını şekillendiren biçimlendirici faktörlerden biri olan egzersizin oynadığı rol, özellikle spora veya egzersize özgü diyet, çevre ve bunların etkileşimleri gibi ilişkili faktörlerin ve stres faktörlerinin bağırsak mikrobiyotasını nasıl etkileyebileceği daha az açıklanmıştır. Bu nedenle, bu sistematik derlemenin amacı, egzersizin sporcuların bağırsak mikrobiyotası ve onu şekillendiren faktörler üzerindeki etkisi ile ilgili literatürü özetlemek ve onu şekillendiren faktörler hakkındaki mevcut bilgileri özetlemektir. Bu çalışma sistematik derleme niteliğindedir ve Aralık 2010–Aralık 2020 tarihleri arasında elektronik veritabanlarından (Pubmed, Web of Science ve EBSCOhost) İngilizce dizinler taranarak gerçekleştirilmiştir. Elektronik veri tabanı sistematik araştırmasında metodoloji olarak Sistematik Derlemeler ve Meta-Analiz Protokolleri için Tercih Edilen Raporlama Öğeleri (The Preferred Reporting Items for Systematic Reviews and MetaAnalyses -PRISMA) temel alınmıştır. Araştırmaya toplam 14 tam metin çalışma dâhil edilmiştir. Çalışmaların büyük çoğunluğunda sporcuların gastrointestinal mikrobiyota bileşimindeki değişiklikler arasında yüksek bir korelasyon olduğunu göstermektedir. Çok kısa vadeli ve orta/uzun vadeli egzersiz programlarının bağırsak mikrobiyotasının bileşimi üzerindeki etkilerine ilişkin raporlar tutarsızdır. Sporcuların bazı bağırsak mikrobiyom çeşitliliğinin egzersize yanıt verebileceğini ve karşılığında sporcu sağlığını ve performansını etkileyebileceği olası mekanizmaları ortaya çıkarmak için daha birçok araştırmaya ihtiyaç vardır.
... Additional studies have investigated the impact of dietary and exercise interventions on the gut microbiota in rodents or in sedentary or otherwise unhealthy human populations (2). Importantly, there is research on the effects of combined exercise and dietary interventions in athletes ( Table 1) (37)(38)(39)(40)(41)(42)(43)(44). ...
... The studies reporting improvement in respiratory symptoms include organisms from the Lactobacilli family (172,173). L. salivarius, may also reduce gastrointestinal permeability via increases in butyrate-producing taxa Roseburia and Lachnospiraceae and decreases in Verrumicrobia (44). While there is evidence of shared mechanisms of probiotic functions, the benefits of probiotics are often dependent on the strain and dose of the probiotic (163,164). ...
The athlete's goal is to optimize their performance. Towards this end, nutrition has been used to improve the health of athletes' brains, bones, muscles, and cardiovascular system. However, recent research suggests that the gut and its resident microbiota may also play a role in athlete health and performance. Therefore, athletes should consider dietary strategies in the context of their potential effects on the gut microbiota, including the impact of sports-centric dietary strategies (e.g., protein supplements, carbohydrate loading) on the gut microbiota as well as the effects of gut-centric dietary strategies (e.g., probiotics, prebiotics) on performance. This review provides an overview of the interaction between diet, exercise, and the gut microbiota, focusing on dietary strategies that may impact both the gut microbiota and athletic performance. Current evidence suggests that the gut microbiota could, in theory, contribute to the effects of dietary intake on athletic performance by influencing microbial metabolite production, gastrointestinal physiology, and immune modulation. Common dietary strategies such as high protein and simple carbohydrate intake, low fiber intake, and food avoidance may adversely impact the gut microbiota and, in turn, performance. Conversely, intake of adequate dietary fiber, a variety of protein sources, and emphasis on unsaturated fats, especially omega-3 (ɷ-3) fatty acids, in addition to consumption of prebiotics, probiotics, and synbiotics, have shown promising results in optimizing athlete health and performance. Ultimately, while this is an emerging and promising area of research, more studies are needed that incorporate, control, and manipulate all 3 of these elements (i.e., diet, exercise, and gut microbiome) to provide recommendations for athletes on how to "fuel their microbes."