Exercise, fitness, and the gut

Connection of pre-competition anxiety with gut microbiota and metabolites in wrestlers with varying sports performances based on brain-gut axis theory

OBJECTIVE

The purpose of this study is to investigate the connection of pre-competition anxiety with gut microbiota and metabolites in wrestlers with different sports performances.

METHODS

One week prior to a national competition, 12 wrestlers completed anxiety questionnaires. Faecal and urine samples were collected for the analysis of gut microbiota and metabolites through the high-throughput sequencing of the 16 S rRNA gene in conjunction with untargeted metabolomics technology. The subjects were divided into two groups, namely, achievement (CP) and no-achievement (CnP) wrestlers, on the basis of whether or not their performances placed them in the top 16 at the competition. The relationship amongst the variations in gut microbiota, metabolites, and anxiety indicators was analyzed.

RESULTS

(1) The CP group exhibited significantly higher levels of "state self-confidence," "self-confidence," and "somatic state anxiety" than the CnP group. Conversely, the CP group displayed lower levels of "individual failure anxiety" and "sports competition anxiety" than the CnP group. (2) The gut microbiota in the CP group was more diverse and abundant than that in the CnP group. Pre-competition anxiety was linked to Oscillospiraceae UCG_005, Paraprevotella, Ruminococcaceae and TM7x. (3) The functions of differential metabolites in faeces and urine of the CP/CnP group were mainly enriched in caffeine metabolism, lipopolysaccharide biosynthesis and VEGF and mTOR signaling pathways. Common differential metabolites in feces and urine were significantly associated with multiple anxiety indicators.

CONCLUSIONS

Wrestlers with different sports performance have different pre-competition anxiety states, gut microbiota distribution and abundance and differential metabolites in faeces and urine. A certain correlation exists between these psychological and physiological indicators.

Resolution of inflammation in chronic disease via restoration of the heat shock response (HSR)

Effective resolution of inflammation via the heat shock response (HSR) is pivotal in averting the transition to chronic inflammatory states. This transition characterizes a spectrum of debilitating conditions, including insulin resistance, obesity, type 2 diabetes, nonalcoholic fatty liver disease, and cardiovascular ailments. This manuscript explores a range of physiological, pharmacological, and nutraceutical interventions aimed at reinstating the HSR in the context of chronic low-grade inflammation, as well as protocols to assess the HSR. Monitoring the progression or suppression of the HSR in patients and laboratory animals offers predictive insights into the organism's capacity to combat chronic inflammation, as well as the impact of exercise and hyperthermic treatments (e.g., sauna or hot tub baths) on the HSR. Interestingly, a reciprocal correlation exists between the expression of HSR components in peripheral blood leukocytes (PBL) and the extent of local tissue proinflammatory activity in individuals afflicted by chronic inflammatory disorders. Therefore, the Heck index, contrasting extracellular 70 kDa family of heat shock proteins (HSP70) (proinflammatory) and intracellular HSP70 (anti-inflammatory) in PBL, serves as a valuable metric for HSR assessment. Our laboratory has also developed straightforward protocols for evaluating HSR by subjecting whole blood samples from both rodents and human volunteers to ex vivo heat challenges. Collectively, this discussion underscores the critical role of HSR disruption in the pathogenesis of chronic inflammatory states and emphasizes the significance of simple, cost-effective tools for clinical HSR assessment. This understanding is instrumental in the development of innovative strategies for preventing and managing chronic inflammatory diseases, which continue to exert a substantial global burden on morbidity and mortality.

Associations Between Physical Activity and Gastrointestinal Transit Times in People with Normal Weight, Overweight, and Obesity

BACKGROUND

Rapid gastric emptying is associated with obesity and overeating, whereas delayed gastric emptying is associated with anorexia. Acute effects of exercise on gastric emptying have been investigated extensively, but the influence of habitual physical activity on gastric emptying and transit time in other regions of the gastrointestinal tract is poorly understood.

OBJECTIVE

The objective was to investigate associations between objectively measured habitual physical activity and gastrointestinal transit times in adults with varying degrees of adiposity.

METHODS

50 adults (58% women) were included in this cross-sectional study. Physical activity was measured by an accelerometer placed on the lower back for 7 d. Gastric emptying time, small bowel transit time, colonic transit time, and whole gut transit time were simultaneously evaluated by a wireless motility capsule, which was ingested together with a standardized mixed meal. Linear regression models were applied to assess the associations of total activity counts and time spent at different intensities-sedentary activity (0-100 counts/min), low light activity (101-759 counts/min), high light activity (760-1951 counts/min); moderate and vigorous activity (≥1952 counts/min)) with gastrointestinal transit times.

RESULTS

Median [Q1; Q3] age was 56.5 [46.6-65.5] y, and body mass index (BMI) was 32.1 [28.5-35.1] kg/m2. For every additional hour spent performing high light intensity physical activity, colonic transit time was 25.5 % [95% CI: 3.10, 42.7] more rapid (P = 0.028), and whole gut transit time was 16.2 % [95% CI: 1.84, 28.4] more rapid (P = 0.028) when adjusted for sex, age, and body fat. No other associations were observed.

CONCLUSIONS

More time spent on physical activity at high light intensity was associated with more rapid colonic and whole gut transit time, independent of age, sex, and body fat, whereas other intensities of physical activity and gastrointestinal transit times were not associated.

TRIAL REGISTRATION

Clinicaltrials.gov IDs (NCT03894670, NCT03854656).

Exercise and the gut microbiome: implications for supportive care in cancer

PURPOSE

Growing recognition of the gut microbiome as an influential modulator of cancer treatment efficacy and toxicity has led to the emergence of clinical interventions targeting the microbiome to enhance cancer and health outcomes. The highly modifiable nature of microbiota to endogenous, exogenous, and environmental inputs enables interventions to promote resilience of the gut microbiome that have rapid effects on host health, or response to cancer treatment. While diet, probiotics, and faecal microbiota transplant are primary avenues of therapy focused on restoring or protecting gut function in people undergoing cancer treatment, the role of physical activity and exercise has scarcely been examined in this population.

METHODS

A narrative review was conducted to explore the nexus between cancer care and the gut microbiome in the context of physical activity and exercise as a widely available and clinically effective supportive care strategy used by cancer survivors.

RESULTS

Exercise can facilitate a more diverse gut microbiome and functional metabolome in humans; however, most physical activity and exercise studies have been conducted in healthy or athletic populations, primarily using aerobic exercise modalities. A scarcity of exercise and microbiome studies in cancer exists.

CONCLUSIONS

Exercise remains an attractive avenue to promote microbiome health in cancer survivors. Future research should elucidate the various influences of exercise modalities, intensities, frequencies, durations, and volumes to explore dose-response relationships between exercise and the gut microbiome among cancer survivors, as well as multifaceted approaches (such as diet and probiotics), and examine the influences of exercise on the gut microbiome and associated symptom burden prior to, during, and following cancer treatment.

A Sedentary Lifestyle Changes the Composition and Predicted Functions of the Gut Bacterial and Fungal Microbiota of Subjects from the Same Company

A sedentary lifestyle affects the diversity and composition of the gut microbiota, but previous studies have mainly focused on bacteria instead of fungi. Here, we compared both the fecal bacterial and fungal microbiota compositions and functions in sedentary persons and controls. Subjects from the China Railway Corporation, including 99 inspectors and 88 officials, were enrolled in our study. Fecal microbiota communities were analyzed using 16S rRNA gene sequencing for bacteria and ITS sequencing for fungi. We found that the diversity of the gut microbiota of the sedentary group was significantly lower than that of the control group (P < 0.05). The sedentary group had a higher abundance of Firmicutes, a lower abundance of Actinobacteria and Proteobacteria and a higher abundance of Ascomycota, and a lower abundance of Basidiomycota. Furthermore, functional prediction analysis of the fungal microbiota revealed more L-tryptophan degradation to 2-amino-3-carboxymuconate semialdehyde, more phospholipid remodeling (phosphatidylethanolamine, yeast), and more L-tyrosine degradation I, as well as less pentose phosphate pathway (non-oxidative branch), less adenosine nucleotide biosynthesis and less L-valine biosynthesis in the sedentary group (P < 0.05). Thus, a sedentary lifestyle changes the composition and function of the gut microbiota. It may change the pentose phosphate pathway (non-oxidative branch), nucleic acid and amino acid biosynthesis and phospholipid metabolism in fungi.

Exercise-induced changes to the human gut microbiota and implications for colorectal cancer: a narrative review

Physical activity is associated with reduced risks of colorectal cancer (CRC) incidence, recurrence and mortality. While these findings are consistent, the mechanism/s underlying this association remain unclear. Growing evidence supports the many ways in which differing characteristics of the gut microbiota can be tumourigenic or protective against CRC. CRC is characterised by significant dysbiosis including reduced short chain fatty acid-producing bacteria. Recent findings suggest that exercise can modify the gut microbiota, and these changes are inverse to the changes seen with CRC; however, this exercise-microbiota interaction is currently understudied in CRC. This review summarises parallel areas of research that are rapidly developing: The exercise-gut microbiota research and cancer-gut microbiota research and highlights the salient similarities. Preliminary evidence suggests that these areas are linked, with exercise mediating changes that promote the antitumorigenic characteristics of the gut microbiota. Future mechanistic and population-specific studies are warranted to confirm the physiological mechanism/s by which exercise changes the gut microbiota, and the influence of the exercise-gut interaction on cancer specific outcomes in CRC.

The feasibility of a crossover, randomized controlled trial design to assess the effect of probiotics and prebiotics on health of elite Swiss para-athletes: a study protocol

BACKGROUND

Spinal cord injury (SCI) may cause an autonomic imbalance in the gastrointestinal tract, leading to deficits in colonic motility, mucosal secretions, vascular tone, and an increase of intestinal barrier permeability. Autonomic denervation and factors such as age, physical activity, antibiotic use and stress may cause intestinal bacterial translocation, decreased microbiota diversity, known as gut dysbiosis and thus increase susceptibility to experiencing gastrointestinal discomfort. Probiotic treatment in individuals with SCI may normalize the gut microbiota and improve overall health. We aim to assess the feasibility of probiotic and prebiotic intervention in athletes with SCI and collect information necessary for sample size calculation of a definite trial on improving health outcomes in para-athletes.

METHODS AND ANALYSIS

Elite Swiss para-athletes (aged> 18 years), being shortlisted for the Paralympic Games 2021 in Tokyo or a member of a national team (n = 43), will be invited to participate in this single-center randomized crossover trial. Athletes suffering from chronic inflammatory bowel diseases, those currently taking antibiotics or other medication to alleviate gastro-intestinal complaints will not be eligible to be included in the study. Athletes will be randomized (1:1) to receive for 4 weeks a daily dose of either 3 g of probiotic preparation or 5 g of prebiotic (organic oat bran) supplementation in addition to usual diet, followed by a 4-week washout period or vice versa. The primary outcome is the feasibility of the study, measured by recruitment and dropout rates, feasibility of the measurements, acceptability and adherence to the intervention. Secondary outcomes include gastrointestinal health assessment, diet and training information, handgrip strength, blood diagnostic parameters, and intestinal microbiome characterization. The changes in clinically relevant secondary outcome values will be used to make a power calculation for definite trial.

DISCUSSION

This pilot trial will address two common challenges in SCI research: the difficulty to recruit enough participants for a sufficiently powered study and the ability to collect data within the limits of a realistic budget and time frame. Upon demonstrated feasibility of the intervention and study procedures, the intervention will be evaluated in a definitive controlled trial comprising a larger sample of para-athletes (elite, engaged, or recreationally active) individuals with a SCI.

TRIAL REGISTRATION

NCT04659408.

Yoga and meditation, an essential tool to alleviate stress and enhance immunity to emerging infections: A perspective on the effect of COVID-19 pandemic on students

The COVID-19 pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) has negatively impacted the global healthcare and economic systems worldwide. The COVID-19 pandemic has also created an emotional and psychological pandemic among people of all ages irrespective of economic status and physical wellbeing. As a consequence of prolonged lockdowns, one of the most severely affected age groups globally is the young adults' group, especially students. Uncertainties in the academic calendar, restricted outdoor activities, and unusual daily routines during lockdowns led to higher incidences of stress, anxiety, and depression among students worldwide. In this review, we summarise the available evidence on the effect of lockdowns on students and discuss possible positive impacts of yoga and meditation on various psychological, emotional, and immunological parameters, which can significantly influence the general wellbeing and academic performance of students. Perspectives shared in the review will also bring awareness on how yoga and meditation could boost students' performance and assist them in maintaining physical and mental wellbeing during stressful conditions such as future epidemics and pandemics with novel infections. This information could help create better educational curriculums and healthy routines for students.

The effects of sustained fitness improvement on the gut microbiome: A longitudinal, repeated measures case-study approach

The athlete gut microbiome differs from that of non-athletes in its composition and metabolic function. Short-term fitness improvement in sedentary adults does not replicate the microbiome characteristics of athletes. The objective of this study was to investigate whether sustained fitness improvement leads to pronounced alterations in the gut microbiome. This was achieved using a repeated-measures, case-study approach that examined the gut microbiome of two initially unfit volunteers undertaking progressive exercise training over a 6-month period. Samples were collected every two weeks, and microbiome, metabolome, diet, body composition, and cardiorespiratory fitness data were recorded. Training culminated in both participants completing their respective goals (a marathon or Olympic-distance triathlon) with improved body composition and fitness parameters. Increases in gut microbiota α-diversity occurred with sustained training and fluctuations occurred in response to training events (eg, injury, illness, and training peaks). Participants' BMI reduced during the study and was significantly associated with increased urinary measurements of N-methyl nicotinate and hippurate, and decreased phenylacetylglutamine. These results suggest that sustained fitness improvements support alterations to gut microbiota and physiologically-relevant metabolites. This study provides longitudinal analysis of the gut microbiome response to real-world events during progressive fitness training, including intercurrent illness and injury.

Gut microbiome associations with breast cancer risk factors and tumor characteristics: a pilot study

OBJECTIVE

To investigate the association between gut microbiome with breast tumor characteristics (receptor status, stage and grade) and known breast cancer risk factors.

METHODS

In a pilot cross-sectional study of 37 incident breast cancer patients, fecal samples collected prior to chemotherapy were analyzed by 16S ribosomal RNA (rRNA) gene-based sequencing protocol. Alpha diversity and specific taxa by tumor characteristics and breast cancer risk factors were tested by Wilcoxon rank sum test, and by differential abundance analysis, using a zero-inflated negative binomial regression model with adjustment for total counts, age and race/ethnicity.

RESULTS

There were no significant alpha diversity or phyla differences by estrogen/progesterone receptor status, tumor grade, stage, parity and body mass index. However, women with human epidermal growth factor receptor 2 positive (HER2+) (n = 12) compared to HER2- (n = 25) breast cancer showed 12-23% lower alpha diversity [number of species (OTU) p = 0.033, Shannon index p = 0.034], lower abundance of Firmicutes (p = 0.005) and higher abundance of Bacteroidetes (p = 0.089). Early menarche (ages ≤ 11) (n = 11) compared with later menarche (ages ≥ 12) (n = 26) was associated with lower OTU (p = 0.036), Chao1 index (p = 0.020) and lower abundance of Firmicutes (p = 0.048). High total body fat (TBF) (> 46%) (n = 12) compared to lower (≤ 46%) TBF was also associated with lower Chao 1 index (p = 0.011). There were other significant taxa abundance differences by HER2 status, menarche age, as well as other tumor and breast cancer risk factors.

CONCLUSIONS AND RELEVANCE

Further studies are needed to identify characteristics of the human microbiome and the interrelationships between breast cancer hormone receptor status and established breast cancer risk factors.

The athletic gut microbiota

The microorganisms in the gastrointestinal tract play a significant role in nutrient uptake, vitamin synthesis, energy harvest, inflammatory modulation, and host immune response, collectively contributing to human health. Important factors such as age, birth method, antibiotic use, and diet have been established as formative factors that shape the gut microbiota. Yet, less described is the role that exercise plays, particularly how associated factors and stressors, such as sport/exercise-specific diet, environment, and their interactions, may influence the gut microbiota. In particular, high-level athletes offer remarkable physiology and metabolism (including muscular strength/power, aerobic capacity, energy expenditure, and heat production) compared to sedentary individuals, and provide unique insight in gut microbiota research. In addition, the gut microbiota with its ability to harvest energy, modulate the immune system, and influence gastrointestinal health, likely plays an important role in athlete health, wellbeing, and sports performance. Therefore, understanding the mechanisms in which the gut microbiota could play in the role of influencing athletic performance is of considerable interest to athletes who work to improve their results in competition as well as reduce recovery time during training. Ultimately this research is expected to extend beyond athletics as understanding optimal fitness has applications for overall health and wellness in larger communities. Therefore, the purpose of this narrative review is to summarize current knowledge of the athletic gut microbiota and the factors that shape it. Exercise, associated dietary factors, and the athletic classification promote a more “health-associated” gut microbiota. Such features include a higher abundance of health-promoting bacterial species, increased microbial diversity, functional metabolic capacity, and microbial-associated metabolites, stimulation of bacterial abundance that can modulate mucosal immunity, and improved gastrointestinal barrier function.

A Review of the Role of the Gut Microbiome in Personalized Sports Nutrition

The gut microbiome is a key factor in determining inter-individual variability in response to diet. Thus, far, research in this area has focused on metabolic health outcomes such as obesity and type 2 diabetes. However, understanding the role of the gut microbiome in determining response to diet may also lead to improved personalization of sports nutrition for athletic performance. The gut microbiome has been shown to modify the effect of both diet and exercise, making it relevant to the athlete's pursuit of optimal performance. This area of research can benefit from recent developments in the general field of personalized nutrition and has the potential to expand our knowledge of the nexus between the gut microbiome, lifestyle, and individual physiology.

Metabolic phenotyping of the human microbiome

The human microbiome has been identified as having a key role in health and numerous diseases. Trillions of microbial cells and viral particles comprise the microbiome, each representing modifiable working elements of an intricate bioactive ecosystem. The significance of the human microbiome as it relates to human biology has progressed through culture-dependent (for example, media-based methods) and, more recently, molecular (for example, genetic sequencing and metabolomic analysis) techniques. The latter have become increasingly popular and evolved from being used for taxonomic identification of microbiota to elucidation of functional capacity (sequencing) and metabolic activity (metabolomics). This review summarises key elements of the human microbiome and its metabolic capabilities within the context of health and disease.

Exercise influence on the microbiome-gut-brain axis

The microbiome in the gut is a diverse environment, housing the majority of our bacterial microbes. This microecosystem has a symbiotic relationship with the surrounding multicellular organism, and a balance and diversity of specific phyla of bacteria support general health. When gut bacteria diversity diminishes, there are systemic consequences, such as gastrointestinal and psychological distress. This pathway of communication is known as the microbiome-gut-brain axis. Interventions such as probiotic supplementation that influence microbiome also improve both gut and brain disorders. Recent evidence suggests that aerobic exercise improves the diversity and abundance of genera from the Firmcutes phylum, which may be the link between the positive effects of exercise on the gut and brain. The purpose of this review is to explain the complex communication pathway of the microbiome-gut-brain axis and further examine the role of exercise on influencing this communication highway.

Consumption of a Fermented Milk Product Containing Bifidobacterium lactis CNCM I-2494 in Women Complaining of Minor Digestive Symptoms: Rapid Response Which Is Independent of Dietary Fibre Intake or Physical Activity

Background. Minor digestive symptoms are common and dietary approaches such as probiotic administration or fibre and fermentable carbohydrate intake adjustments are often recommended. A Fermented Milk Product (FMP) containing Bifidobacterium animalis subsp. lactis CNCM I-2494 and lactic acid bacteria has been shown to improve digestive symptoms after 4 weeks of consumption, but the speed of onset of this effect and its dependence on fibre intake or physical activity is unknown. To answer these questions, data from two previously published trials on FMP for minor digestive symptoms were combined. Methods. In total, 538 participants provided weekly assessments of bloating, abdominal pain/discomfort, flatulence, borborygmi/rumbling stomach from which a composite score was calculated. At baseline in one study (n = 336), dietary fibre consumption was recorded and physical activity classified as high, moderate or low. The speed of the FMP's effect was assessed by a repeated measure analysis of variance measuring the change from baseline for the composite score of digestive symptoms. Results. FMP consumption resulted in a significant decrease in the composite score of symptoms after only 2 weeks in both studies and the pooled data at week 1 (-0.35 [-0.69, 0.00]; p = 0.05), week 2 (-0.66 [-1.04, -0.27]; p < 0.001), week 3 (-0.49 [-0.89, -0.10]; p = 0.01) and week 4 (-0.46 [-0.88, -0.04]; p = 0.03). The interactions fibre intake-by-product group, physical activity-by-product group and time-by-product group were not statistically significant. Conclusion. FMP consumption leads to a rapid improvement in symptoms which is likely to encourage adherence to this dietary intervention. This effect is independent of dietary fibre and physical activity.

EXTREMELY LOW TESTOSTERONE DUE TO RELATIVE ENERGY DEFICIENCY IN SPORT: A CASE REPORT

Objective

Recognize extremely low testosterone due to hypothalamic dysfunction from overtraining syndrome in a male athlete with relative energy deficiency in sport (RED-S).

Methods

Clinical and laboratory information are described.

Results

A 20-year-old male division I collegiate swimmer was found to have strikingly low total, free, and bioavailable testosterone levels with normal sex hormone-binding globulin and inappropriately normal follicle-stimulating hormone and luteinizing hormone. Lab testing ruled out hyperprolactinemia and hypothyroidism as etiologies, and pituitary imaging was normal. A diagnosis of RED-S was made, and the patient worked with the sports medicine team to increase nutrition and modify physical activity. His repeat testosterone levels improved after minor weight gain and decreased training regimen and eventually returned to normal.

Conclusion

Secondary hypogonadism with extremely low testosterone can be seen in male athletes with suspected RED-S.

Exercise and gut microbiota: clinical implications for the feasibility of Tai Chi

Recent studies have shown exercise is associated with changes in the gut microbiota in humans as well as in experimental animals. Tai Chi is an exercise that integrates a martial art, deep breathing and mediation, and has various beneficial effects for health. This review summarizes current knowledge and recent literature on the association between exercise and gut microbiota, and explores the feasibility of Tai Chi for improving gut microbiota composition and function. PubMed/MEDLINE was used to search the English literature for the keywords exercise and gut microbiota. Fourteen relevant studies were identified. In humans, exercise increases the gut microbial diversity. However, the evidence for this association is weak, as previous studies were small-scale, non-controlled studies of short duration or cross-sectional design. In animals, exercise alters the composition of gut microbiota, with some studies suggesting exercise increases the Bacteroidetes/Firmicutes ratio. However, these results are controversial, partly because host genetics and physical fitness also influence gut microbiota. Furthermore, the intensity of exercise may play a key role in how exercise affects gut microbiota. Tai Chi is a moderate-intensity exercise that improves immune function and inflammation of the gut. Tai Chi may also affect gut microbiota through vagal modulation and mediating the hypothalamic-pituitary-adrenal axis. However, no studies have investigated the association between Tai Chi and gut microbiota. Well designed studies exploring the effects of Tai Chi on gut microbiota are needed.

Effects of pre-exercise sucrose ingestion on thermoregulatory responses to near-maximal 5-km running

Research has shown that carbohydrate consumption can increase body temperature at rest and, in some cases, during exercise. Most exercise studies, however, haven't matched exercise intensity between carbohydrate and placebo conditions. The purpose of this randomized, double-blind, placebo-controlled trial was to examine whether pre-exercise carbohydrate consumption independently accelerates the usual temperature rise with intense exercise. Twenty-eight runners self-reported 5-km performance (16-23 min) and were randomized, using a matched-pairs design, to 750 ml water containing 100 g sucrose or 0.8 g aspartame. Beverages were consumed 60 min before running at 93% of maximum 5-km speed in temperate conditions. Gastrointestinal temperature, Thermal Sensation Scale (TSS) and Feeling Scale (FS) were recorded before ingestion, every 10 min during 60 min of rest, and every 1-km during the 5-km run. Rating of Perceived Exertion was recorded every 1-km. Independent samples t-tests and two-way mixed ANOVAs with repeated measures assessed whether there were baseline differences or treatment effects. Gastrointestinal temperature didn't differ between carbohydrate (38.7 ± 0.4 °C) and placebo (38.6 ± 0.4 °C) by the end of the 5-km (p = 0.49). No group x time interactions or main group effects were found, except for a modest interaction for TSS (F = 2.1, p = 0.02, partial η² = 0.075). Time effects were found for all outcomes, with temperature, TSS, and RPE increasing, and FS decreasing, during the run. Ingesting 100 g of sucrose prior to intense running lasting < 25 min didn't influence gastrointestinal temperature and therefore doesn't likely impact on the risk of heat illness.

A Prospective Metagenomic and Metabolomic Analysis of the Impact of Exercise and/or Whey Protein Supplementation on the Gut Microbiome of Sedentary Adults

The gut microbiota of humans is a critical component of functional development and subsequent health. It is important to understand the lifestyle and dietary factors that affect the gut microbiome and what impact these factors may have. Animal studies suggest that exercise can directly affect the gut microbiota, and elite athletes demonstrate unique beneficial and diverse gut microbiome characteristics. These characteristics are associated with levels of protein consumption and levels of physical activity. The results of this study show that increasing the fitness levels of physically inactive humans leads to modest but detectable changes in gut microbiota characteristics. For the first time, we show that regular whey protein intake leads to significant alterations to the composition of the gut virome.

Many components of modern living exert influence on the resident intestinal microbiota of humans with resultant impact on host health. For example, exercise-associated changes in the diversity, composition, and functional profiles of microbial populations in the gut have been described in cross-sectional studies of habitual athletes. However, this relationship is also affected by changes in diet, such as changes in dietary and supplementary protein consumption, that coincide with exercise. To determine whether increasing physical activity and/or increased protein intake modulates gut microbial composition and function, we prospectively challenged healthy but sedentary adults with a short-term exercise regime, with and without concurrent daily whey protein consumption. Metagenomics- and metabolomics-based assessments demonstrated modest changes in gut microbial composition and function following increases in physical activity. Significant changes in the diversity of the gut virome were evident in participants receiving daily whey protein supplementation. Results indicate that improved body composition with exercise is not dependent on major changes in the diversity of microbial populations in the gut. The diverse microbial characteristics previously observed in long-term habitual athletes may be a later response to exercise and fitness improvement.

IMPORTANCE The gut microbiota of humans is a critical component of functional development and subsequent health. It is important to understand the lifestyle and dietary factors that affect the gut microbiome and what impact these factors may have. Animal studies suggest that exercise can directly affect the gut microbiota, and elite athletes demonstrate unique beneficial and diverse gut microbiome characteristics. These characteristics are associated with levels of protein consumption and levels of physical activity. The results of this study show that increasing the fitness levels of physically inactive humans leads to modest but detectable changes in gut microbiota characteristics. For the first time, we show that regular whey protein intake leads to significant alterations to the composition of the gut virome.

The microbiome of professional athletes differs from that of more sedentary subjects in composition and particularly at the functional metabolic level

OBJECTIVE

It is evident that the gut microbiota and factors that influence its composition and activity effect human metabolic, immunological and developmental processes. We previously reported that extreme physical activity with associated dietary adaptations, such as that pursued by professional athletes, is associated with changes in faecal microbial diversity and composition relative to that of individuals with a more sedentary lifestyle. Here we address the impact of these factors on the functionality/metabolic activity of the microbiota which reveals even greater separation between exercise and a more sedentary state.

DESIGN

Metabolic phenotyping and functional metagenomic analysis of the gut microbiome of professional international rugby union players (n=40) and controls (n=46) was carried out and results were correlated with lifestyle parameters and clinical measurements (eg, dietary habit and serum creatine kinase, respectively).

RESULTS

Athletes had relative increases in pathways (eg, amino acid and antibiotic biosynthesis and carbohydrate metabolism) and faecal metabolites (eg, microbial produced short-chain fatty acids (SCFAs) acetate, propionate and butyrate) associated with enhanced muscle turnover (fitness) and overall health when compared with control groups.

CONCLUSIONS

Differences in faecal microbiota between athletes and sedentary controls show even greater separation at the metagenomic and metabolomic than at compositional levels and provide added insight into the diet-exercise-gut microbiota paradigm.

Gastrointestinal Conditions in the Female Athlete

Exercise can have significant effects on gastrointestinal diseases. Regular, moderate exercise can impart beneficial effects for the intestinal microbiome, irritable bowel syndrome symptoms, and inflammatory bowel disease. High-intensity training or prolonged endurance training, on the other hand, can have negative effects on these same entities. Female athletes report a higher prevalence of irritable bowel syndrome and celiac disease, and furthermore, have gastrointestinal symptoms modulated by the menstrual cycle. Management of gastrointestinal problems in the athletic population is widespread and includes training adjustments, dietary measures, and medicine management of symptoms.

Hypoxia and inactivity related physiological changes precede or take place in absence of significant rearrangements in bacterial community structure: The PlanHab randomized trial pilot study

We explored the assembly of intestinal microbiota in healthy male participants during the randomized crossover design of run-in (5 day) and experimental phases (21-day normoxic bed rest (NBR), hypoxic bed rest (HBR) and hypoxic ambulation (HAmb) in a strictly controlled laboratory environment, with balanced fluid and dietary intakes, controlled circadian rhythm, microbial ambiental burden and 24/7 medical surveillance. The fraction of inspired O₂ (F_iO₂) and partial pressure of inspired O₂ (P_iO₂) were 0.209 and 133.1 ± 0.3 mmHg for NBR and 0.141 ± 0.004 and 90.0 ± 0.4 mmHg for both hypoxic variants (HBR and HAmb; ~4000 m simulated altitude), respectively. A number of parameters linked to intestinal environment such as defecation frequency, intestinal electrical conductivity (IEC), sterol and polyphenol content and diversity, indole, aromaticity and spectral characteristics of dissolved organic matter (DOM) were measured (64 variables). The structure and diversity of bacterial microbial community was assessed using 16S rRNA amplicon sequencing. Inactivity negatively affected frequency of defecation and in combination with hypoxia increased IEC (p < 0.05). In contrast, sterol and polyphenol diversity and content, various characteristics of DOM and aromatic compounds, the structure and diversity of bacterial microbial community were not significantly affected over time. A new in-house PlanHab database was established to integrate all measured variables on host physiology, diet, experiment, immune and metabolic markers (n = 231). The observed progressive decrease in defecation frequency and concomitant increase in IEC suggested that the transition from healthy physiological state towards the developed symptoms of low magnitude obesity-related syndromes was dose dependent on the extent of time spent in inactivity and preceded or took place in absence of significant rearrangements in bacterial microbial community. Species B. thetaiotamicron, B. fragilis, B. dorei and other Bacteroides with reported relevance for dysbiotic medical conditions were significantly enriched in HBR, characterized with most severe inflammation symptoms, indicating a shift towards host mucin degradation and proinflammatory immune crosstalk.

Endurance exercise and gut microbiota: A review

BACKGROUND

The physiological and biochemical demands of intense exercise elicit both muscle-based and systemic responses. The main adaptations to endurance exercise include the correction of electrolyte imbalance, a decrease in glycogen storage and the increase of oxidative stress, intestinal permeability, muscle damage, and systemic inflammatory response. Adaptations to exercise might be influenced by the gut microbiota, which plays an important role in the production, storage, and expenditure of energy obtained from the diet as well as in inflammation, redox reactions, and hydration status.

METHODS

A systematic and comprehensive search of electronic databases, including MEDLINE, Scopus, ClinicalTrials.gov, ScienceDirect, Springer Link, and EMBASE was done. The search process was completed using the keywords: "endurance", "exercise", "immune response", "microbiota", "nutrition", and "probiotics".

RESULTS

Reviewed literature supports the hypothesis that intestinal microbiota might be able to provide a measureable, effective marker of an athlete's immune function and that microbial composition analysis might also be sensitive enough to detect exercise-induced stress and metabolic disorders. The review also supports the hypothesis that modifying the microbiota through the use of probiotics could be an important therapeutic tool to improve athletes' overall general health, performance, and energy availability while controlling inflammation and redox levels.

CONCLUSION

The present review provides a comprehensive overview of how gut microbiota may have a key role in controlling the oxidative stress and inflammatory responses as well as improving metabolism and energy expenditure during intense exercise.

Hypoxia and Inactivity Related Physiological Changes (Constipation, Inflammation) Are Not Reflected at the Level of Gut Metabolites and Butyrate Producing Microbial Community: The PlanHab Study

We explored the assembly of intestinal microbiota in healthy male participants during the run-in (5 day) and experimental phases [21-day normoxic bed rest (NBR), hypoxic bedrest (HBR)], and hypoxic ambulation (HAmb) in a strictly controlled laboratory environment, balanced fluid, and dietary intakes, controlled circadian rhythm, microbial ambiental burden, and 24/7 medical surveillance. The fraction of inspired O₂ (F_iO₂) and partial pressure of inspired O₂ (P_iO₂) were 0.209 and 133.1 ± 0.3 mmHg for NBR and 0.141 ± 0.004 and 90.0 ± 0.4 mmHg for both hypoxic variants (HBR and HAmb; ~4,000 m simulated altitude), respectively. A number of parameters linked to intestinal transit spanning Bristol Stool Scale, defecation rates, zonulin, α₁-antitrypsin, eosinophil derived neurotoxin, bile acids, reducing sugars, short chain fatty acids, total soluble organic carbon, water content, diet composition, and food intake were measured (167 variables). The abundance, structure, and diversity of butyrate producing microbial community were assessed using the two primary bacterial butyrate synthesis pathways, butyryl-CoA: acetate CoA-transferase (but) and butyrate kinase (buk) genes. Inactivity negatively affected fecal consistency and in combination with hypoxia aggravated the state of gut inflammation (p < 0.05). In contrast, gut permeability, various metabolic markers, the structure, diversity, and abundance of butyrate producing microbial community were not significantly affected. Rearrangements in the butyrate producing microbial community structure were explained by experimental setup (13.4%), experimentally structured metabolites (12.8%), and gut metabolite-immunological markers (11.9%), with 61.9% remaining unexplained. Many of the measured parameters were found to be correlated and were hence omitted from further analyses. The observed progressive increase in two immunological intestinal markers suggested that the transition from healthy physiological state toward the developed symptoms of low magnitude obesity-related syndromes was primarily driven by the onset of inactivity (lack of exercise in NBR) that were exacerbated by systemic hypoxia (HBR) and significantly alleviated by exercise, despite hypoxia (HAmb). Butyrate producing community in colon exhibited apparent resilience toward short-term modifications in host exercise or hypoxia. Progressive constipation (decreased intestinal motility) and increased local inflammation marker suggest that changes in microbial colonization and metabolism were taking place at the location of small intestine.

Exercise-induced stress behavior, gut-microbiota-brain axis and diet: a systematic review for athletes

Fatigue, mood disturbances, under performance and gastrointestinal distress are common among athletes during training and competition. The psychosocial and physical demands during intense exercise can initiate a stress response activating the sympathetic-adrenomedullary and hypothalamus-pituitary-adrenal (HPA) axes, resulting in the release of stress and catabolic hormones, inflammatory cytokines and microbial molecules. The gut is home to trillions of microorganisms that have fundamental roles in many aspects of human biology, including metabolism, endocrine, neuronal and immune function. The gut microbiome and its influence on host behavior, intestinal barrier and immune function are believed to be a critical aspect of the brain-gut axis. Recent evidence in murine models shows that there is a high correlation between physical and emotional stress during exercise and changes in gastrointestinal microbiota composition. For instance, induced exercise-stress decreased cecal levels of Turicibacter spp and increased Ruminococcus gnavus, which have well defined roles in intestinal mucus degradation and immune function.

Diet is known to dramatically modulate the composition of the gut microbiota. Due to the considerable complexity of stress responses in elite athletes (from leaky gut to increased catabolism and depression), defining standard diet regimes is difficult. However, some preliminary experimental data obtained from studies using probiotics and prebiotics studies show some interesting results, indicating that the microbiota acts like an endocrine organ (e.g. secreting serotonin, dopamine or other neurotransmitters) and may control the HPA axis in athletes. What is troubling is that dietary recommendations for elite athletes are primarily based on a low consumption of plant polysaccharides, which is associated with reduced microbiota diversity and functionality (e.g. less synthesis of byproducts such as short chain fatty acids and neurotransmitters). As more elite athletes suffer from psychological and gastrointestinal conditions that can be linked to the gut, targeting the microbiota therapeutically may need to be incorporated in athletes’ diets that take into consideration dietary fiber as well as microbial taxa not currently present in athlete’s gut.

Gut Microbiome and Gastrointestinal Cancer: Les liaisons Dangereuses

Gastrointestinal (GI) cancers are the leading cause of mortality worldwide. These cancers are the end result of a complex interplay between gene and environment. Bacteria, parasites, and viruses have been implicated in some cancers. Recent data have put at focus the gut microbiome as the key player firing tumorigenesis. Experimental and human studies have provided evidence on the role of microbiota in cancer development. Although subject to changes in different settings such as antibiotic treatment, diet or lifestyle, our microbiome is quite stable and is capable of increasing susceptibility to cancer or decrease and halt its progression. The crucial event in carcinogenesis triggered by microbiome seems to be chronic inflammation influencing the genomic stability of host cells and activating immune mechanisms. Infection-related cancers represent 5.5% of the global cancer burden. Chronic inflammation predisposes to cancer in various GI organs, including hepatocellular carcinoma caused by hepatitis B or hepatitis C virus-related chronic hepatitis, gastric cancer (GC) caused by Helicobacter pylori-associated chronic gastritis, colorectal cancer caused by inflammatory bowel disease, bile duct cancer by primary sclerosing cholangitis, and esophageal cancer caused by Barrett esophagus. Apart from its impact in GI cancer development microbiota can also play an important role in the progression of cancer, response to chemotherapy or cancer prevention. In this review we will discuss the role of microbiome in GI cancers in the light of the current literature and the possible therapeutic options targeting microbiota in the near future.

Comparison of Diet versus Exercise on Metabolic Function and Gut Microbiota in Obese Rats

Cardiometabolic impairments that begin early in life are particularly critical, because they often predict metabolic dysfunction in adulthood. Obesity, high-fat diet (HFD), and inactivity are all associated with adipose tissue (AT) inflammation and insulin resistance (IR), major predictors of metabolic dysfunction. Recent evidence has also associated the gut microbiome with cardiometabolic health.

PURPOSE

The objective of this study is to compare equal energy deficits induced by exercise and caloric reduction on cardiometabolic disease risk parameters including AT inflammation, IR, and gut microbiota changes during HFD consumption.

METHODS

Obesity-prone rats fed HFD were exercise trained (Ex, n = 10) or weight matched to Ex via caloric reduction although kept sedentary (WM, n = 10), and compared with ad libitum HFD-fed (Sed, n = 10) rats for IR, systemic energetics and spontaneous physical activity (SPA), adiposity, and fasting metabolic parameters. Visceral, subcutaneous, periaortic, and brown AT (BAT), liver, aorta, and cecal digesta were examined.

RESULTS

Despite identical reductions in adiposity, Ex, but not WM, improved IR, increased SPA by approximately 26% (P < 0.05 compared with WM and Sed), and reduced LDL cholesterol (P < 0.05 compared with Sed). WM and Ex both reduced inflammatory markers in all AT depots and aorta, whereas only Ex increased indicators of mitochondrial function in BAT. Ex significantly increased the relative abundance of cecal Streptococcaceae and decreased S24-7 and one undefined genus in Rikenellaceae; WM induced similar changes but did not reach statistical significance.

CONCLUSIONS

Both Ex and WM reduced AT inflammation across depots, whereas Ex caused more robust changes to gut microbial communities, improved IR, increased fat oxidation, increased SPA, and increased indices of BAT mitochondrial function. Our findings add to the growing body of literature indicating that there are weight-loss-independent metabolic benefits of exercise.