Table 5.
Systematic review search results, included studies that investigated the impact of prebiotic, probiotic and synbiotic supplementation on markers of EIGS and associated GIS in response to an acute exercise bout.
| References | Population and study design | Sample size determination | Supplementation protocol | Physical activity/dietary control | Exercise protocol | Outcome/s reported |
|---|---|---|---|---|---|---|
| Probiotic studies | ||||||
| Axelrod et al. (63) |
n = 7 endurance runners, VO2max 57.9 mL/kg/min RXT |
A priori power analysis based on a previous investigation from healthy runners (64) estimated ~6 needed to obtain statistical power at the recommended 0.80 level based upon mean, between-groups comparison effect size (d = 1.2). |
L. salivarius UCC118, 2 × 108 CFU/cap 1 capsule daily for 4 wk |
Normal lifestyle (not monitored) | Treadmill running: 2 h at 60% VO2max.
Tamb: 25°C, RH: 31% |
Intestinal permeability Cytokine responses |
| Batatinha et al. (65) |
n = 27 male marathon runners, age: Int: 35.96 ± 5.81; Pla: 40.46 ± 7.79 Fitness status not stated RCT |
Not specified |
B. animalis. Lactis 10 × 109; L. Acidophilus 10 × 109
1 sachet daily for 30 days |
Training volume monitored, NS between groups. Dietary control not stated. |
Marathon race: Race time was 4.08 ± 0.55 h Tabm not stated |
Cytokine responses |
| Gill et al. (68) |
n = 8 male runners and triathletes Age: 26 yrs VO2max 59 ml/kg/min RXT |
Based on the typical standard deviation of 0.7 EU/ml for circulatory endotoxin responses to exertional-stress (16, 69), and using standard alpha (0.05) and beta values (0.8) (www.dssresearch.com), a sample size of n = 8 is estimated to provide adequate statistical precision to detect a >10% difference in circulatory endotoxin concentration in response to EHS in the target population. |
L. casei, 1.0 × 1011 cells/bottle Commercial supplement, taken twice daily for 7 days |
Dietary recall. Activity control not stated. |
Treadmill running: 2 h at 60% VO2max.
Tamb: 34°C, RH: 32% |
Endotoxaemia Cytokine responses |
| Kekkonen et al. (99) |
n = 119 (125M/16F recruited) marathon competitors, Best marathon time Int: 3:10 (2:35–3:42) Pla: 3:11 (2:23–3:40) Age 40 yrs. RCT |
Not specified | Milk-based fruit drink or capsules (participant choice) containing L. rhamnosus GG, 4.0 × 1010 CFU 2 × 65 mL bottles or capsules daily for 3 months |
Diary questionnaire with ready-made questions Training diaries, NS for running sessions or weekly distance. |
Helsinki Marathon, 2003: Int: 3 h 32 min Pla: 3 h 30 min |
GIS |
| Lamprecht et al. (76) |
n = 23 male triathletes, runners and cyclists Age, Int: 37.6 yrs, Pla: 38.2 yrs VO2max: Int: 51.2 mL/kg/min Pla: 50.3 mL/kg/min RCT |
Sample size calculation based on oxidation markers CP and MDA. Between 7 and 9 subjects estimated per group—depending on parameter, SD and effect size—to reach probability of error (alpha/2) of 5 and 80% power. | Ecologic® Performance: B. bifidum W23, B lactis W51, E. faecium W54, L. acidophilus W22, L. brevis W63, L. lactis W58. 2 × 2 g sachets daily for 14 wk, providing (1010 CFU/day) | Habitual diet, food diary and repeated for 7 days prior to each exercise trial. Habitual training, no exercise 3 days prior to each exercise test. | 3 × incremental “step” tests on cycling ergometer to exhaustion, with 15 min active recovery between each test. Total test time ~80–90 min. Tamb: 20°C, RH: 60% RH | Cytokine responses |
| Pugh et al. (79) | n = 24 (20M/4F) marathon runners, age: Int: 34.8 ± 6.9 yrs Pla: 36.1 ± 7.5 yrs VO2max: Int: 57.6 ± 8.0 mL/kg/min Pla: 56.4 ± 8.6 mL/kg/min RCT | Not specified |
Proven Probiotics Ltd., Port Talbot, Wales: L. acidophilus CUL60 L. acidophilus CUL21 B. bifidum CUL20 B. animalis subsp. Lactis CUL34 (). >25 billion CFU/cap 1 capsule daily for 4 wk |
Dietary control not stated outside of acute exercise. Training not stated. | Non-sanctioned marathon (outdoor running track). Finish time: Int: 234 ± 38 min, Pla: 247 ± 47 NS % LT: Int: 90.2 ± 9.1, Pla: 91.3 ± 8.7 NS |
Intestinal permeability Intestinal injury Cytokine responses GIS |
| Pugh et al. (100) |
n = 7 male cyclists Age: 23 ± 4 yrs VO2peak 64.0 ± 2.2 mL/kg/min RXT |
To detect a meaningful increase in exogenous CHO oxidation of 0.1 g/min with SD = 0.05 g/min (101) at 80% power, a minimum n = 5 required. | Proven Probiotics Ltd., Port Talbot, Wales: L. acidophilus CUL60 L. acidophilus CUL21 B. bifidum CUL20 B. animalis subsp. Lactis CUL34 (). >25 billion CFU/cap 1 capsule daily for 4 wk |
Not stated | Cycle ergometer: 2 h at 55% Wmax followed by 100 kJ time trial. Ambient conditions not stated |
Intestinal permeability Intestinal injury Cytokine responses GIS |
| Schreiber et al. (82) |
n = 27 male cyclists Age: Int: 25.9 ± 4.6 Pla: 29.5 ± 6.2 VO2max (mL/kg/min) Int: 66.9 ± 6.4 Pla: 63.2 ± 5.0 RCT |
Not specified | 1 capsule containing: L. helveticus Lafti L10 (28.6%), B. animalis ssp. lactis Lafti B94 (28.6%), E. faecium R0026 (25.7%), Bifidobacterium longum R0175 (14.3%) B. subtilis R0179 (2.8%) 15 × 109 CFU/cap 1 capsule daily for 90 days |
Diet not controlled. “Difference in training hours during the study period” (Data not shown) |
Evaluation (online survey) at training, competition, and during the first 2 h recovery from training or competition. | GIS |
| Shing et al. (102) |
n = 10 male runners Age: 27 ± 2 yrs VO2max: 62.6 ± 2.1 mL/kg/min RXT |
Sample size was determined to detect a treatment difference at a two-sided 5% significance level with a probability of 80% from primary outcome variables of lactulose/rhamnose and LPS. The lactulose:rhamnose ratio following exercise is reported to be 0.0625 (SD 0.0125) (103). Assuming that probiotics reduced the lactulose:rhamnose by 20% (similar to reduction following bovine colostrum supplementation) (104), a total of eight runners were required. Recent literature has shown a 20% increase in LPS concentration following running in the heat with an increase in training load (105). Assuming that probiotics reduced LPS concentration by 20% (post-exercise LPS concentration of 27 pg mL−1 with a within-subject standard deviation of 5 pg mL−1), a total of nine runners were required. Based on these calculations, 10 runners were recruited for the present study. | UltraBiotic45, BioCeuticals™: L. acidophilus, 7.4 × 109 CFU/cap L. rhamnosus, 15.55 × 109 CFU/cap L. casei, 9.45 × 109 CFU/cap L. plantarum, 3.15 × 109 CFU/cap L. fermentum, 1.35 × 109 CFU/cap B. lactis, 4.05 × 109 CFU/cap B. breve, 1.35 × 109 CFU/cap B. bifidum, 0.45 × 109 CFU/cap S. thermophilus, 2.25 × 109 CFU/cap 1 capsule daily for 4 wk |
Food diary NS between trials. Required to avoid strenuous exercise for 24 h prior to each testing session. |
Treadmill running: time to fatigue at 80% ventilatory threshold. Tamb: 35°C, RH: 40% |
Intestinal permeability Intestinal injury Endotoxaemia Cytokine responses GIS |
| Tavares-Silva et al. (87) |
N = 14 male marathon runners Age: Pla: 38.28 ± 3.09 Int: 41.57 ± 3.20 VO2Peak: Pla: 54.53 ± 6.88 kg/mL/min Int: 56.92 ± 8.35 kg/mL/min RCT |
Not specified |
L. acidophilus-LB-G80, L. paracasei-LPc-G110, Lactococcus subp. lactis-LLL-G25, B. animalis subp. lactis-BL-G101, B. bifidum-BB-G90 Capsules containing 5 × 109 CFU / day |
Physical activity control not stated. Questionnaire 2 × /wk + once on weekends: Energy intake (kcal) Pla: 1,994.46 ± 365.73 Int: 2,434.69 ± 505.53 NS difference between groups |
Marathon race Race Time (min) Pla: 243.0 ± 33.73 Int: 252.87 ± 39.77 NS Difference Tamb: 21.5°C, RH: 67%. |
Cytokine responses |
| Vaisberg et al. (89) |
n = 42 male marathon runners Age: Int: 39.6 ± 8.8 yrs, Pla: 40.1 ± 10.3 yrs VO2max: Int: 57.64 ± 6.89 mL/kg/min, Pla: 57.86 ± 6.85 mL/kg/min RCT |
Not specified |
Lactobacillus casei Shirota, 40 × 109 live cells/bottle 1 × 80 g bottle daily for 30 days |
Dietary control not stated. Instructed to keep usual training/physical exercise schedules—not reported |
Marathon race Ambient conditions not stated |
Cytokine responses |
| West et al. (90) |
n = 88 cyclists and triathletes Age: Int: M: 35.2 yrs, F: 36.5 yrs, Pla: M: 36.4 yrs, F 35.6 VO2max (mL/kg/min): Int: M: 56.5, F: 57.6 Pla: M: 55.8, F: 51.6 RCT |
A sample size of 80 subjects was required for identifying substantial changes in the incidence of illness, assuming a rate of URTI symptoms of 60% in the placebo group, with sufficient power (86% at an alpha-level of 0.05) to detect a 50% reduction in symptoms. |
Lactobacillus fermentum VRI-003 PCC®, 109 CFU/cap 1 capsule daily for 11 wk |
4 d food diary. Usual diet, without probiotic foods. Training log kept |
Incremental cycling ergometer test (VO2max protocol). Ambient conditions not stated |
Cytokine responses |
| Synbiotic studies | ||||||
| Roberts et al. (94) |
n = 20 (9M/1F) long course triathletes VO2max: Int: 47.6 mL/kg/min Pla: 50.5 mL/kg/min RCT |
Power calculation assessment for sample size (G*power3, Dusseldorf (95); using α = 0.05; 1 – β = 0.80; based on observed data. |
Bio-Acidophilus Forte, Biocare Ltd., Birmingham, UK): L. acidophilus CUL-60 (NCIMB 30157), 1010 CFU/cap L. acidophillus CUL-21 (NCIMB 30156), 1010 CFU/cap B. bifidum CUL-20 (NCIMB 30172), 9.510 CFU/cap B. animalis subspecies lactis CUL-34 (NCIMB 30153), 0.510 CFU/cap. Fructooligosaccharides, 55.8 mg per cap 1 capsule daily for 12 wk |
Habitual diet, food diary first and last wk of each month. NS between groups or over intervention time period. Prescribed triathlon training program, individualized. NS between groups for training load throughout intervention period. |
Ironman triathlon. Mean finish time: Int: 12 h 47 min, Pla: 14 h 12 min NS | Endotoxin responses Intestinal permeability |
| Valle et al. (96) |
n = 65 (39M/26F) military personnel Age: Pla: 19.5 ± 1.22, Int: 19.69 ± 1.25 Fitness status not stated RCT |
Sample calculation in G * Power 3.1.9.2 software was based on the following data: 5% sample error, 95% CI and 0.72 effect size considering pre and post-intervention IgA values. The effect size was estimated based on the study by Olivares et al. (97). |
Lactobacillus acidophilus LA-5, 10·3 log CFU
Bifidobacterium animalis BB-12, 11·0 log CFU Inulin, 2.3 g 60g serve of ice cream, daily for 30 days |
Participants recommended not to consume any foods containing prebiotics and probiotics 15 d before the beginning of the research period, particularly over the weekend, when they are released to go home. During the week all food was provided. Not reported, however participants were undergoing military training. |
5 d military training, including physical and psychological exhaustion, marching 8–20 km, carrying ~ 30 kg equipment, sleep deprivation. Subject to various weather extremes. |
Bacterial taxa Fecal SCFA GIS |
RCT, Randomized control trial; RXT, Randomized crossover trial; Cap, capsule; Tamb, Ambient temperature; RH, Relative humidity; Int, Intervention; Pla, Placebo; NS, Not significant; wk, week.