Characteristics of the gut microbiome of Swiss elite athletes with a spinal cord injury: An exploratory study

OBJECTIVES

To illustrate and explore associations between the gut microbiome and spinal cord injury (SCI) characteristics, physical training, dietary intake, body composition, and blood biomarkers of elite Swiss athletes.

DESIGN AND SETTING

Baseline data analysis of athletes with SCI who participated in a pilot trial (NCT04659408) in the Swiss Paraplegic Center, Nottwil, Switzerland.

PARTICIPANTS

Elite athletes, five males, and six females, with SCI who competed internationally.

OUTCOME MEASURES

We conducted a differential abundance analysis and measured the alpha and beta diversity of the gut microbiome.

RESULTS

The athletes' median age was 34.5 years. Six had traumatic SCI and five had a spina bifida. The athletes competed in para-cycling (5), wheelchair athletics (3), and wheelchair tennis (3). A higher duration of training per week was positively associated with Akkermansia and Akkermansiaceae but negatively associated with Prevotellaceae. Muribaculaceae was negatively associated with the average number of trainings per week. Waist circumference is negatively associated with Butyricimonas. Significant differences in the alpha diversity were found with sex, gastrointestinal quality of life index (GIQLI) scores, total caloric intake, total fat intake, total carbohydrate intake, and high-sensitivity C-reactive protein (hs-CRP). Beta diversity differences were found with impairment of the sympathetic nervous system of the gut at the genus level and HbA1c at the family level.

CONCLUSIONS

This study provides insight into the gut microbiome of athletes with SCI. Our results were similar to those found in athletes without SCI. Further replication is needed to confirm the relationships of organisms observed in the gut of athletes with SCI.

Reliability of a Submaximal Field Test in Wheelchair Rugby

The aim was to investigate the test-retest reliability of performance and physiological variables of a submaximal wheelchair rugby field test. Eight trained wheelchair rugby athletes with a spinal cord injury (age: median 40, interquartile range 6.9 y; body mass: median 77.7, interquartile range 23.9 kg) performed a submaximal field test two times with a duration of 41 min, split up into four sets of eight min. Each set included eight laps with one eight-meter sprint (SP8) and one four-meter sprint (SP4). The absolute and relative reliability and the performance decrease (fatigue) across the sets were investigated. The examined variables were sprinting time, heart rate, and RPE. The measured parameters showed moderate (peak heart rate ICC3,1=0.663, peak rate of perceived exertion ICC3,1=0.718), good (SP4 ICC3,1=0.874), and excellent (mean heart rate ICC3,1=0.905, SP8 ICC3,1=0.985) test-retest reliability. Fatigue was observed for SP8 in test 2 between set 2/3 and set 2/4. For test 1 a significant decrease of performance for SP4 was found between set 2/3, set 2/4 and between set 3/4. In conclusion the submaximal field test showed moderate to excellent reliability for all measured parameters. The observed fatigue seems to be not clinically relevant. The test can be recommended to assess the effects of training or interventions.

Sports Nutrition Knowledge in Athletes with a Spinal Cord Injury and Coaches of Para Sports

Sports nutrition for athletes with a spinal cord injury (SCI) is complex, making it challenging for athletes to stay informed. The aim of this study was to assess sports nutrition knowledge in athletes with a SCI and coaches of para sports. The secondary aim was to report sources of sports nutrition information. Eighty athletes and twenty-six coaches across various adapted sports were recruited. The Nutrition for Sport Knowledge Questionnaire was used to assess nutrition knowledge for both groups. Athletes achieved their highest score among the alcohol (65 ± 19%) category and the lowest in sports nutrition (43 ± 17%). Coaches demonstrated the most knowledge in the alcohol (73 ± 17%) category and lowest knowledge in the supplementation (45 ± 19%) category. Both groups relied on the internet, dietitians, and coaches for sports nutrition information. Future studies should explore the effects of nutrition education on nutrition knowledge and dietary intakes among these populations.

Physical activity and cardiometabolic risk factors in individuals with spinal cord injury: a systematic review and meta-analysis

Physical inactivity in individuals with spinal cord injury (SCI) has been suggested to be an important determinant of increased cardiometabolic disease (CMD) risk. However, it remains unclear whether physically active SCI individuals as compared to inactive or less active individuals have truly better cardiometabolic risk profile. We aimed to systematically review and quantify the association between engagement in regular physical activity and/or exercise interventions and CMD risk factors in individuals with SCI. Four medical databases were searched and studies were included if they were clinical trials or observational studies conducted in adult individuals with SCI and provided information of interest. The Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach was applied to rate the certainty of evidence. Of 5816 unique citations, 11 randomized clinical trials, 3 non-randomized trial and 32 cross-sectional studies comprising more than 5500 SCI individuals were included in the systematic review. In meta-analysis of RCTs and based on evidence of moderate certainty, physical activity in comparison to control intervention was associated with: (i) better glucose homeostasis profile [WMD of glucose, insulin and Assessment of Insulin Resistance (HOMA-IR) were - 3.26 mg/dl (95% CI - 5.12 to - 1.39), - 3.19 μU/ml (95% CI - 3.96 to - 2.43)] and - 0.47 (95% CI - 0.60 to - 0.35), respectively], and (ii) improved cardiorespiratory fitness [WMD of relative and absolute oxygen uptake relative (VO2) were 4.53 ml/kg/min (95% CI 3.11, 5.96) and 0.26 L/min (95% CI 0.21, 0.32) respectively]. No differences were observed in blood pressure, heart rate and lipids (based on evidence of low/moderate certainty). In meta-analysis of cross-sectional studies and based on the evidence of very low to low certainty, glucose [WMD - 3.25 mg/dl (95% CI - 5.36, - 1.14)], insulin [- 2.12 μU/ml (95% CI - 4.21 to - 0.03)] and total cholesterol [WMD - 6.72 mg/dl (95% CI - 13.09, - 0.34)] were lower and HDL [WMD 3.86 mg/dl (95% CI 0.66, 7.05)] and catalase [0.07 UgHb-1 (95% CI 0.03, 0.11)] were higher in physically active SCI individuals in comparison to reference groups. Based on limited number of cross-sectional studies, better parameters of systolic and diastolic cardiac function and lower carotid intima media thickness were found in physically active groups. Methodologically sound clinical trials and prospective observational studies are required to further elaborate the impact of different physical activity prescriptions alone or in combination with other life-style interventions on CMD risk factors in SCI individuals.

Characteristics of Official Wheelchair Basketball Games in Hot and Temperate Conditions

This study compared performance parameters of two wheelchair basketball games under hot (30.3 °C, 52% relative humidity) and temperate (21.6 °C, 30% relative humidity) environmental conditions and described the characteristics of wheelchair basketball. Eight wheelchair basketball players from two teams were monitored during two games using an indoor position tracking system. Total distance, mean- and peak-speed, playing-time, number of sprints, sprints per minute, heart rate and rate of perceived exertion were recorded. Additionally, athletes with a lesion level above and below T6 were compared. No measured parameter differed between the games. Across quarters (Q) mean velocity (m/s) (Q1: 1.01; Q2: 1.10; Q3: 1.18; Q4: 1.06; p < 0.001) and sprints per minute (Q1: 16; Q2: 14; Q3: 23; Q4: 14; p = 0.033) differed significantly, independent of the conditions. Descriptive statistics did not reveal differences between the groups with a lesion level below or above T6. In the present study, hot environmental conditions seemed not to have an impact on activity parameters of wheelchair basketball players. It was speculated that the game intensity and therefore metabolic heat production was too low; consequently, the athletes had a sufficient heat loss to prevent a decrease in performance during the play in hot conditions.

Vitamin D supplementation in chronic spinal cord injury (VitD-SCI): study protocol for a randomised controlled trial

INTRODUCTION

Vitamin D insufficiency, a vitamin D status or serum 25(OH)D concentration of ≤75 nmol/L, is highly prevalent in individuals with a spinal cord injury (SCI). Vitamin D is important for the functioning of the musculoskeletal, immune and respiratory systems, which are relevant determinants of secondary health conditions in SCI. An insufficiency should be treated with vitamin D supplementation. However, there is a lack of evidence regarding the optimal dosage and duration of vitamin D supplementation for individualised and long-term management of the vitamin D status in the context of SCI. This paper presents the protocol for the vitamin D supplementation in chronic spinal cord injury (VitD-SCI) trial that aims to investigate the effect of a 12-month intake of vitamin D supplementation on vitamin D status as well as on several secondary parameters among individuals with a chronic SCI.

METHODS AND ANALYSES

The VitD-SCI trial is a randomised, placebo-controlled, double-blinded, parallel-group, superiority trial, conducted at the Swiss Paraplegic Centre. A total of 45 participants living with an SCI for at least 3 years (chronic SCI) and a vitamin D insufficiency at the first study visit, will be randomly assigned to one of three intervention groups. Participants receive either a monthly dosage of 24 000 IU or 48 000 IU vitamin D or a placebo for 12 months. Measurements taking place every 3 months include the assessment of vitamin D status (primary outcome) as well as bone mineral density, handgrip strength, fatigue, mood, pain and pressure injuries (secondary outcomes). Safety and tolerance of vitamin D supplementation will also be evaluated.

ETHICS AND DISSEMINATION

The Swiss Ethics Committee for Northwest/Central Switzerland (EKNZ, 2020-01493) and the Swiss Agency for Therapeutic Products (Swissmedic, 2020DR3150) approved this study. Findings will be disseminated through peer-reviewed publications.

TRIAL REGISTRATION NUMBERS

NCT04652544 and SNCTP000004032.

Systematic Review of the Effects of Oat Intake on Gastrointestinal Health

BACKGROUND

Oats are a food source with multiple health benefits that could support beneficial bacterial groups and provide important bioactive compounds for the gut.

OBJECTIVES

This review explores the association between oat intake, gastrointestinal (GI) symptoms, and microbial community changes in individuals with celiac disease (CeD), irritable bowel syndrome (IBS), and inflammatory bowel disease (IBD) and without GI disease.

METHODS

Four databases and Google Scholar were systematically searched from inception until April 29, 2021. Clinical trials, observational studies, and in vitro studies with human gut-derived samples were included.

RESULTS

There were 84 articles [23 randomized controlled trials (RCTs), 21 nonrandomized trials, 8 observational studies, and 32 in vitro studies] included. Oat intake increased total bacterial count, Lactobacilli spp., and Bifidobacterium spp. in healthy individuals and those with CeD. There was an increased concentration of short-chain fatty acids and improved gut permeability with oat intake but with no significant quality-of-life difference. In some individuals with CeD, consumption of certain oat types was associated with worsening of GI symptoms. We found no studies reporting on IBS and only 3 for IBD. The quality of RCTs showed some concerns mostly in domains of randomization (73.9%), whereas the quality of evidence of non-RCTs, observational studies, and in vitro studies was satisfactory.

CONCLUSIONS

Oat intake was associated with the increase of beneficial bacterial groups in individuals without GI disease and those with CeD. Most studies showed no changes in GI symptoms with oat consumption. In vitro studies in CeD provide insight to oat-sensitive individuals and their GI mucosa, but the clinical studies remain limited, precluding our ability to draw firm conclusions. The prevalence of oat sensitivity in individuals with CeD should be further explored as this could improve clinical management and facilitate inclusion of oat in the diet for this population.

Protein Considerations for Athletes With a Spinal Cord Injury

Athlete participation in the Paralympic games is steadily increasing; prompting research focused on the unique needs of this population. While the Paralympic Games includes a diversity of athletes, athletes with a spinal cord injury (PARA-SCI) represent a subgroup that requires specialized recommendations. Nutritional guidelines designed to optimize performance, in the context of the neurological impairments, are required. This narrative review summarizes the current literature regarding the importance of dietary protein for optimal health and performance. Factors with the potential to affect protein needs in PARA-SCI including loss of active muscle mass, reduced energy expenditure, and secondary complications are examined in detail. Furthermore, we analyze protein intakes in PARA-SCI from the available research to provide context around current practices and trends. In conclusion, we make the case that protein recommendations for able-bodied athletes may not be directly transferable to PARA-SCI. Consequently, PARA-SCI need their own guidelines to maximize performance and ensure long-term health.

The Thermoregulatory and Thermal Responses of Individuals With a Spinal Cord Injury During Exercise, Acclimation and by Using Cooling Strategies-A Systematic Review

Background: In individuals with a spinal cord injury thermoregulatory mechanisms are fully or partially interrupted. This could lead to exercise-induced hyperthermia in temperate conditions which can be even more distinct in hot conditions. Hyperthermia has been suggested to impair physiological mechanisms in athletes, which could negatively influence physical performance and subjective well-being or cause mild to severe health issues.

Objective: The aim was to evaluate the literature on the thermoregulatory and thermal responses of individuals with a spinal cord injury during exercise in temperate and hot conditions taking the effects of cooling techniques and heat acclimation into account.

Data sources: Two electronic databases, PubMed and Web of Science were searched. Studies were eligible if they observed the influence of exercise on various thermoregulatory parameters (e.g., core and skin temperature, sweat rate, thermal sensation) in individuals with a spinal cord injury.

Results: In total 32 articles were included of which 26 were of strong, 3 of moderate and 3 of weak quality. Individuals with a high lesion level, especially those with a tetraplegia, reached a higher core and skin temperature with a lower sweat rate. The use of cooling techniques before and during exercise can positively affect the burden of the impaired thermoregulatory system in all individuals with a spinal cord injury.

Conclusion: Due to the absence of normal thermoregulatory abilities, individuals with a high-level spinal cord injury need special attention when they are exercising in temperate and hot conditions to prevent them from potential heat related issues. The use of cooling techniques can reduce this risk.

Key Nutritional Considerations for Youth Winter Sports Athletes to Optimize Growth, Maturation and Sporting Development

Despite a wealth of sport nutrition guidelines for adult athletes, there are currently no nutrition guidelines for youth winter sports athletes. Whilst it may be pragmatic to apply nutrition guidelines for adult athletes to youth winter sports athletes, it is inappropriate. Due to a paucity of research on youth athletes, it is impossible to provide evidence-based guidelines for this population, so careful extrapolation from the theoretical and practical considerations that apply to other athletic groups is necessary. Youth winter sport athletes undergo rapid biological growth and maturation which influences their nutritional requirements. A varied and balanced diet that ensures sufficient energy availability for optimal growth and maturation as well as sporting performance is the cornerstone of youth athlete nutrition and should also allow for youth athletes to meet their micronutrient requirements. In some cases, micronutrient status (e.g., vitamin D and iron) should be monitored and optimized if appropriate by a medical professional. Dietary supplement use is prevalent amongst youth athletes, however is often unnecessary. Education of youth athletes, their parents and coaches on best nutritional practices as well as the risks associated with dietary supplements is vital for their long-term athletic development. Further research in youth winter sports athletes across different stages of growth and maturation competing in a variety of sports is urgently required in order to inform nutritional guidelines for this population.

Energy Availability in Male and Female Elite Wheelchair Athletes over Seven Consecutive Training Days

Background: Low energy availability (LEA) is a major problem as athletes often restrict their energy intake. It has been shown that LEA occurs often in female and endurance athletes and in athletes from weight-sensitive or aesthetic sports. The purpose of this study was to investigate energy availability (EA) in elite wheelchair athletes. Methods: Fourteen elite wheelchair athletes (8 males; 6 females) participated. Data were collected using a weighed seven-day food and training diary to estimate energy intake and exercise energy expenditure. Resting energy expenditure and body composition were measured, whereas energy balance (EB) was calculated. Results: Measured over 7 days, EA was significantly different (36.1 ± 6.7 kcal kg⁻¹ FFM day⁻¹) in male compared to female (25.1 ± 7.1 kcal kg⁻¹ FFM day⁻¹) athletes (p < 0.001). From all analyzed days, LEA occurred in 73% of the days in female athletes and in 30% of the days in male athletes. EB was positive in male athletes (+169.1 ± 304.5 kcal) and negative (−288.9 ± 304.8 kcal) in female athletes. Conclusions: A higher prevalence of LEA was found in female compared to male athletes. A higher energy intake would be recommended to meet energy needs and to maximize training adaptation.

Body Composition in Swiss Elite Wheelchair Athletes

The aim of this study was to retrospectively interpret body composition in various wheelchair athletes. In total, 69 athletes (mean ± standard deviation; age 33 ± 11 years; body mass 65.1 ± 14.8 kg; height 169.9 ± 14.9 cm and time since injury 19 ± 11 years) from different national teams in wheelchair sports underwent a dual X-ray absorptiometry (DXA) measurement during the yearly medical check-up. The data showed a significant difference between total fat and total fat-free mass between male (fat mass: 15.1 ± 7.6 kg; fat-free mass: 51.8 ± 9.3 kg) and female (fat mass: 19.4 ± 7.8 kg; fat-free mass: 36.8 ± 7.6 kg) athletes (p = 0.032, p < 0.001). In contrast, no significant difference (p = 0.16, p = 0.07) in fat and fat-free mass between paraplegic, tetraplegic and non-SCI athletes was found. Comparing different sports, the lowest fat mass was found in paracycling athletes whereas curling game players showed the highest total fat mass. Basketball game players showed the highest fat-free mass (fat-free mass: 54.8 ± 10.1 kg). In tetraplegic athletes, difference in fat-free mass between left and right arms correlated with the upper extremity motor score. For the interpretation of the data it seems to be crucial, that many different parameters (i.e., gender, motor level of the injury) are taken into consideration in wheelchair athletes.

Acute Effects of Caffeine on Heart Rate Variability, Blood Pressure and Tidal Volume in Paraplegic and Tetraplegic Compared to Able-Bodied Individuals: A Randomized, Blinded Trial

Caffeine increases sympathetic nerve activity in healthy individuals. Such modulation of nervous system activity can be tracked by assessing the heart rate variability. This study aimed to investigate the influence of caffeine on time- and frequency-domain heart rate variability parameters, blood pressure and tidal volume in paraplegic and tetraplegic compared to able-bodied participants. Heart rate variability was measured in supine and sitting position pre and post ingestion of either placebo or 6 mg caffeine in 12 able-bodied, 9 paraplegic and 7 tetraplegic participants in a placebo-controlled, randomized and double-blind study design. Metronomic breathing was applied (0.25 Hz) and tidal volume was recorded during heart rate variability assessment. Blood pressure, plasma caffeine and epinephrine concentrations were analyzed pre and post ingestion. Most parameters of heart rate variability did not significantly change post caffeine ingestion compared to placebo. Tidal volume significantly increased post caffeine ingestion in able-bodied (p = 0.021) and paraplegic (p = 0.036) but not in tetraplegic participants (p = 0.34). Systolic and diastolic blood pressure increased significantly post caffeine in able-bodied (systolic: p = 0.003; diastolic: p = 0.021) and tetraplegic (systolic: p = 0.043; diastolic: p = 0.042) but not in paraplegic participants (systolic: p = 0.09; diastolic: p = 0.33). Plasma caffeine concentrations were significantly increased post caffeine ingestion in all three groups of participants (p<0.05). Plasma epinephrine concentrations increased significantly in able-bodied (p = 0.002) and paraplegic (p = 0.032) but not in tetraplegic participants (p = 0.63). The influence of caffeine on the autonomic nervous system seems to depend on the level of lesion and the extent of the impairment. Therefore, tetraplegic participants may be less influenced by caffeine ingestion.

Vitamin D deficiency in Swiss elite wheelchair athletes

STUDY DESIGN

This is a retrospective analysis of total serum 25-hydroxyvitamin D (25[OH]D) in Swiss elite wheelchair athletes.

OBJECTIVES

The aim was to investigate the occurrence of vitamin D deficiency in Swiss elite wheelchair athletes over the whole year and to detect differences between winter and summer months, and between indoor and outdoor athletes.

SETTING

This study was conducted in Switzerland.

METHODS

A total of 164 blood samples from 72 Swiss elite wheelchair athletes (mean±s.d.: age 32±13 years) were analyzed for total serum 25[OH]D. All participants were members of the national team in their discipline. The following disciplines have been included: rugby, athletics, cycling, tennis, ski alpine, curling and basketball. According to general guidelines, insufficient vitamin D status was defined between 50 and 75 nmol l^-1, deficiency below 50 nmol l^-1 and severe deficiency below 27.5 nmol l^-1.

RESULTS

In all, 73.2% of all samples showed an insufficiency/deficiency in vitamin D status. Total serum 25[OH]D was significantly higher during summer compared with winter months (69.5±21.4 nmol l^-1 vs 51.5±21.9 nmol l^-1; P<0.001). Indoor sports showed a higher amount of vitamin D insufficiency/deficiency (80.9%) than outdoor sports (70.1%), with a significantly higher 25[OH]D concentration in outdoor sports (P=0.042).

CONCLUSION

A high percentage of vitamin D deficiency was found among Swiss elite wheelchair athletes. Conclusively, we recommend supplementation with vitamin D-especially during winter-to prevent a deficiency and an impairment of performance.

Is beetroot juice more effective than sodium nitrate? The effects of equimolar nitrate dosages of nitrate-rich beetroot juice and sodium nitrate on oxygen consumption during exercise

Dietary nitrate has been reported to lower oxygen consumption in moderate- and severe-intensity exercise. To date, it is unproven that sodium nitrate (NaNO3(-); NIT) and nitrate-rich beetroot juice (BR) have the same effects on oxygen consumption, blood pressure, and plasma nitrate and nitrite concentrations or not. The aim of this study was to compare the effects of different dosages of NIT and BR on oxygen consumption in male athletes. Twelve healthy, well-trained men (median [minimum; maximum]; peak oxygen consumption: 59.4 mL·min(-1)·kg(-1) [40.5; 67.0]) performed 7 trials on different days, ingesting different nitrate dosages and placebo (PLC). Dosages were 3, 6, and 12 mmol nitrate as concentrated BR or NIT dissolved in plain water. Plasma nitrate and nitrite concentrations were measured before, 3 h after ingestion, and postexercise. Participants cycled for 5 min at moderate intensity and further 8 min at severe intensity. End-exercise oxygen consumption at moderate intensity was not significantly different between the 7 trials (p = 0.08). At severe-intensity exercise, end-exercise oxygen consumption was ~4% lower in the 6-mmol BR trial compared with the 6-mmol NIT (p = 0.003) trial as well as compared with PLC (p = 0.010). Plasma nitrite and nitrate concentrations were significantly increased after the ingestion of BR and NIT with the highest concentrations in the 12-mmol trials. Plasma nitrite concentration between NIT and BR did not significantly differ in the 6-mmol (p = 0.27) and in the 12-mmol (p = 0.75) trials. In conclusion, BR might reduce oxygen consumption to a greater extent compared with NIT.

Reliability of a 3-min all-out Arm Crank Ergometer Exercise Test

The 3-min all-out test is a well-established exercise test developed for cycling ergometry. However, no such test exists in arm cranking. Thus the aim of this study was to investigate the test-retest reliability of a 3-min all-out exercise test on an arm crank ergometer. 21 healthy participants (9 male and 12 female, age 34±11 years, body mass 69.6±11.1 kg and height 175.5±6.9 cm) twice performed a 3-min all-out exercise test on an arm crank ergometer separated by 7 days. Peak power (PP), mean power (MP), fatigue index (FI), time to peak (TTP) and total work (TW) were assessed to detect test-retest reliability. PP, MP, FI and TW showed an excellent intra-class correlation coefficient (ICC) ranging from 0.940 to 0.984. Only TTP showed very low reliability with an ICC of 0.379. The results from this test-retest analysis showed that all parameters except the TTP were highly reliable in a 3-min all-out exercise test on an arm crank ergometer in able-bodied participants.