Table 3.
Systematic review search results and study characteristics of included studies that attempted to determine the impact of prebiotic, probiotic and synbiotic supplementation on gastrointestinal outcomes at rest.
| References | Population and study design | Sample size determination | Supplementation protocol (vs. placebo or control) |
Dietary control (DC)
Physical activity (PA) |
Outcome/s reported |
|---|---|---|---|---|---|
| Prebiotic studies | |||||
| Damen et al. (55) |
N = 27 (10 M and 17 F), age: 25 (IQR 23–29) years, activity/fitness: not stated, study design: RXT |
Not specified | Bread fortified with xylanase to produce Arabinoxylan oligosaccharides (AXOS) on baking. 180 g bread (7.2 g arabinoxylan) daily for 3 wk. | DC: Usual diet, not monitored. PA: Physical activity not stated |
Gastrointestinal function GIS Bacterial taxa Fecal SCFA |
| Finegold et al. (56) |
n = 32 (11M/21F), age (M 23–34 yrs, F 21–49 yrs) (activity not stated) RCT |
Not specified | Xylooligosaccharides (XOS), up to 350 mg per cap. High (2.8 g) or low (1.4 g) dose from capsules, daily for 8 wk | Instructed to avoid high XOS/FOS/GOS foods and pre/probiotics and fermented foods. Twenty-four hour dietary recall used to compare between groups (data not reported). | Bacterial taxa Fecal SCFA GIS |
| François et al. (57) |
n = 63 (M33/F30), age 42 yrs (activity not stated) RXT |
Based on dataset of an earlier human intervention trial with WBE (58), an evaluable sample size of n = 40 was expected to provide 80% power (two-sided, α = 0·05) for detecting statistically significant difference in fecal bifidobacterial levels (primary outcome variable) between treatments. | Non-carbonated soft drink with wheat bran extract [containing Arabinoxylan oligosaccharides (AXOS)]. High (8 g/d) or Low (2.4 g/d) dose AXOS taken in a 70 mL drink, twice daily for 3 wk | Usual diet, 3 meals/day pattern, no pro/prebiotics. All food and beverage intake recorded for first 3 days of each study period. No activity monitoring stated. | Bacterial taxa Fecal SCFA GIS |
| Kleessen et al. (59) |
n = 45 (10M/35F), age 23.5 yrs (activity not stated) RCT |
Not specified | Snack bar with chicory inulin (CH) or Jerusalem artichoke inulin (JA), 7.7 g fructans per bar. 1 bar/d for 1 wk, 2 bars/d for 2 wk. | Asked to maintain usual habits (not monitored) | Bacterial taxa Fecal SCFA Gastrointestinal function GIS |
| Reimer et al. (60) |
N = 48 (22M/28F at recruitment) Age 31.2 ± 9.1/30.5 ± 8.6 (Trial 1/ 2) (healthy untrained) RXT |
The study was powered on the primary outcome of change in gut microbiota, which for the purposes of sample size calculation was based on changes in fecal Bifidobacterium from a previous trial (59). A sample size of n = 25 per group was determined to have 80% power to detect a difference between groups in fecal Bifidobacterium counts (CFU/g) assuming a 1.10-log difference with SD = 1.22 log, an α = 0.05, and a dropout rate of ~25%. |
Snack bar with inulin type fructans (ITF) Int 1: moderate dose 7 g/d inulin + 2 g wheat based fiber Int 2: low dose 3 g/d inulin + 2 g oat based fiber Con 1: snack bar (0 g inulin, 0 g fiber) Con 2: snack bar (0 g inulin, 1 g fiber) 1 bar/d for 4 wk. |
3 day weighed food record. Energy (kcal), protein, carbohydrate, fat @ baseline and within trialsNS Fiber time × treatment, trial 1 (P = 0.001), trial 2 (P = 0.019). Exercise across both trials, bw or within-group differencesNS (data not shown). | Bacterial taxa Fecal SCFA GIS Gastrointestinal function |
| Russo et al. (61) | n = 15 males, age 18.8 ± 0.7 yrs (activity not stated) RXT | Not specified | Inulin-enriched pasta: Int: 11.0 g/d fructans Pla: 1.4 g/d fructans 100 g/day pasta for 5 wk |
All food provided, low inulin, amount calculated according to individual requirements. No activity monitoring stated. | Gastrointestinal function GIS |
| Russo et al. (45) |
n = 20 males, age 18.8 ± 0.7 yrs (activity not stated) RXT |
Not specified | Inulin-enriched pasta: Int: 11.0 g/d fructans Pla: 1.4 g/d fructans 100 g/day pasta for 5 wk |
All food provided, low inulin, amount calculated according to individual requirements. No activity monitoring stated. | Gastrointestinal function |
| Russo et al. (62) |
n = 20 males, age 18.8 ± 0.7 yrs (activity not stated) RXT |
Sample size calculations based on data from Russo et al. (45) and Russo et al. (61). Probability that study would detect treatment difference with a 2-sided 0.05 significance level equal to 80% required enrolling only 17 subjects. This assumed true difference between treatments of 20% of urinary recovery of La, and standard deviation of the difference of 27%. |
Inulin-enriched pasta: Int: 11.0 g/d fructans Pla: 1.4 g/d fructans 100 g/day pasta for 5 wk |
All food provided, low inulin, amount calculated according to individual requirements. No activity monitoring stated. | Intestinal permeability |
| 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 Activity not monitored |
Intestinal permeability Cytokine responses Bacterial taxa |
| 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 |
Dietary control not stated. Training volume monitored, NS between groups. |
Cytokine responses |
| Burton et al. (66) |
n = 13 males age 24 (22–27) yrs (activity not stated) RXT |
The desired sample number could not be determined because of the absence of previous clinical studies with a similar intervention. | Yogurt containing: S. thermophilus (109 CFU/g), L. delbrueckii spp. bulgaricus (108 CFU/g) L. rhamnosus GG (107 CFU/g) 400 g daily for 2 wk |
Avoid dairy and fermented foods, 3 d food record each trial. 3 d control diet (provided) before each test day. Usual activity. Avoid intense activity 3 d prior to testing. NS difference between groups |
Endotoxin responses Cytokine responses Bacterial taxa |
| Carbuhn et al. (67) |
n = 17 female swimmers, age and fitness status not stated RCT |
Not specified |
B. longum 35624, 1 × 109 CFU bacteria per capsule 1 capsule daily for 6 wk |
Refrain from foods rich in probiotics (ex. Kefir) and caffeine. Three day food log (NSbetween groups). Standardized swim training program |
Endotoxin responses 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. NS between groups. Activity control not stated. |
Cytokine responses Endotoxin responses |
| Gleeson et al. (70) |
n = 58 (54M/30F recruited) athletes Age: Int: 32 ± 14, Pla: 25 ± 9 yrs Weekly training load: Int: 8.7 ± 4.1 h/week Pla: 9.3 ± 3.8 h/week RCT |
Sample-size based on expected rate of 2.0 ± 1.0 URTI episodes (M ± SD) (71), a target 30% reduction in number of episodes, statistical power of 80%, and Type I error of 5%. | Fermented milk with L. casei Shirota, 6.5 × 109 live cells/drink 65 ml drink twice daily for 16 wk | Diet not monitored, no other probiotics or fermented dairy products. Training validated by International Physical Activity Questionnaire, NSbetween groups | Cytokine responses GIS |
| Haywood et al. (72) | n = 30 male rugby union players, age 24.7 ± 3.6 yrs RCT | In order to detect a 30% reduction in the number of infected days with 80% power and type 1 error of 5%, n = 25 participants were required. | Probiotica P3, Nutra-life: L. gasseri, 2.6 × 109 CFU/cap B. bifidum, 0.2 × 109 organisms/cap B. longum, 0.2 × 109 organisms/cap 1 capsule daily for 4 wk |
Dietary control not stated. Standardized training program. |
GIS |
| Hoffman et al. (73) |
n = 15 male military recruits, age: Int: 20.0 ± 0.6, Pla: 20.2 ± 0.6 Fitness status not stated; military training. RCT |
Because of the small sample size per group, it was decided a priori to initially analyze PRE-to-POST changes (Δ scores) using the non-parametric Mann-Whitney U test. In addition, to make additional inferences on the true effect of the dietary intervention, and account for the small sample size per group, magnitude-based inferential analysis was also used. | Staimune, Kerry Inc. (St Paul, MN). Inactivated Bacillus coagulans; 1.0 × 109 CFU (powder form) Daily for 2 wk | Participants were not permitted to use any additional dietary supplementation. All soldiers consumed their meals together, maintaining a similar dietary intake throughout the study. During study period, soldiers were garrisoned on base and participated in the same training tasks that included hand-to-hand combat skill development, working with and against various weapons and physical conditioning 5 times a week. |
Cytokine responses |
| Huang et al. (74) |
n = 20 male triathletes Age: Int: 21.6 ± 1.3 Pla: 21.9 ± 1.4 VO2max mL/kg/min): Int: 55.5 ± 8.6 Pla: 56.6 ± 9.0 RCT |
Not specified | L. plantarum PS128, 2 capsules; 1.5 × 1010 CFU + 100 mg microcrystalline cellulose (per capsule) 4 wk | Diet not monitored. Participants were required not to supplement with fermented food, probiotics, prebiotics, and antibiotics during the whole experimental process. Training not controlled. Maintain a regular lifestyle, avoiding any strenuous exercise, staying up late, smoking, or consuming alcoholic beverages. |
Bacterial taxa Fecal SCFA |
| Klein et al. (75) |
n = 26 (13M/13F), age 25 yrs (activity not stated) RXT |
Power analysis performed using PASS 6.0 (NCSS Statistical Software, Kaysville, UT, USA). Based on data from the literature and study group to evaluate sample size. It resulted in a power of 90%. |
300 g yogurt containing B. lactis 420 ×, 3.0 × 106 CFU/g L. acidophilus 74-2, 9.3 × 108 CFU/g 300 g daily for 5 wk | Food provided and additional foods aliquoted and analyzed (NSbetween groups). Activity not stated. |
Bacterial taxa Fecal SCFA |
| 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. |
Intestinal permeability Cytokine responses |
| Lee et al. (77) |
n = 16 healthy untrained males Age Int 24.6 ± 2.8, Pla: 25.6 ± 4.1 VO2max: Int: 47.3 ± 6.5, Pla: 46.6 ± 8.2 RCT |
The required sample sizes for clinical trials based on expected change calculated using Harvard calculator (http://hedwig.mgh.harvard.edu/sample_size/size.html, accessed on 14 December 2020), assuming parallel design with 0.05 significance level, the change SD, power of 0.8, standard deviation of the difference with 3.2. | Synkefir: L. paracasei DSM 32785 (LPC12), L. rhamnosus DSM 32786 (LRH10), L. helveticus DSM 32787 (LH43), L. fermentum DSM 32784 (LF26), and S. thermophilus DSM 32788 (ST30) 20 g pouch daily for 28 days |
All volunteers were prohibited from taking probiotics, prebiotic fermented products (yogurt or cheese), vitamins, minerals, herbal extracts, dietary supplements for exercise, or antibiotics to avoid unnecessary interference during the experiment. No significant difference on their daily nutritional intake and calories (data not shown). Activity not stated. | Bacterial taxa |
| Lin et al. (78) |
n = 21 (14M, 7F) well trained middle and long distance runners. Fitness status not reported. Age: Pla: 21.2 ± 0.4 Int: 21.6 ± 0.7 RCT |
Not specified | OLP-01, a human strain probiotic; Bifidobacterium longum subsp. Longum 3 capsules daily (1.5 × 1010 CFU/day) for 5 wk |
Instructed not to consume nutritional supplements, yogurt, Yakult, other probiotic-related products, or antibiotics during the experiment. The team dietitian specified the diet and provided the same meal to ensure the consistency of the diet (Data not shown). Three weeks of regular training and 2 weeks of de-training. During the experiment, all the subjects cooperated with the team for work and rest (Data not shown). |
Bacterial taxa |
| 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 diary kept during supplementation period (data not presented). |
GIS |
| Sánchez Macarro et al. (80) |
n = 43 healthy male volunteers who performed aerobic physical exercise. VO2max= 51.1 (8.8)mL/kg/min Age: Int: 25.3 ± 7.2, Pla: 27.1 ± 8.4 RCT |
The sample size was calculated for an expected mean difference between groups in serum levels of MDA of 1.34 nmol/mL with SD of 1.6 nmol/L (81), with significance level of 5% and statistical power of 80%, assuming a drop-out rate of 10% since the primary analysis was performed in the PP data set, 20 evaluable participants for each treatment group were required. | Bifidobacterium longum CECT 7347 Lactobacillus casei CECT 9104, and Lactobacillus rhamnosus CECT 8361 1 capsule daily (109 CFU/day) for 6 wk | No dietary control: During the study period, there were no dietary restrictions, but medications that may affect the microbiome (e.g., antioxidants, statins) were not allowed. Physical activity not controlled |
Bacterial taxa |
| 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 NS difference between groups RCT |
Not specified |
L. helveticus Lafti L10, B. animalis ssp. lactis Lafti B94 E. faecium R0026, B. longum R0175 Bacillus subtilis R0179 15 × 109 CFU of a probiotic blend: 1 capsule daily for 90 days |
Diet not controlled. Continued with their normal training routine throughout the study duration. “Participants' characteristics analysis revealed difference in training hours during the study period.” Data not shown. |
GIS Cytokine responses |
| Smarkusz-Zarzecka et al. (83) |
n = 66 (46M/20F) runners, age: Int: F 37.21 ± 8.09 y M 40.85 ± 8.32 y Pla: F 33.33 ± 8.73 y M 38.61 ± 8.84 y VO2max (mL/kg/min) Int: male: 38.22 ± 5.99 Female:34.02 ± 5.30 Pla: male: 42.34 ± 7.06 female:36.98 ±11.34 RCT |
Not specified | Sanprobi Barrier, Sanprobi Ltd., Szczecin, Poland: Bifidobacterium lactis W52, Lactobacillus brevis W63, Lactobacillus casei W56, Lactococcus lactis W19, Lactococcus lactis W58, Lactobacillus acidophilus W37, Bifidobacterium bifidum W23, Lactobacillus salivarius W24. 2.5 × 109 CFU/g (1 capsule); 2 capsules, twice daily for 3 months. |
Diet not controlled. Avoid physical activity for at least 24 h before the test. |
Cytokine responses |
| Son et al. (84) |
n = 15 bodybuilders (biological sex and fitness status not stated) Age: Int: 26.50 ± 5.01 Pla: 27.14 ± 5.93 RCT |
Not specified |
L. acidophilus, L. casei, L. helveticus, Bifidobacterium bifidum 1 capsule consisting of 1012 CFU For 60 days |
The subjects were periodically monitored to ensure that nutritional intake was not altered during the supplement intake period; There was no significant difference in the characteristics of the study subjects before and after the probiotic intake period. Data not shown. Physical activity not monitored. |
Bacterial taxa Fecal SCFA |
| Strasser et al. (85) |
n = 29 (13M/16F) cyclists Age: Int: 25.7 ± 3.5 yrs, Pla: 26.6 ± 3.5 yrs VO2max: Int: 55.1 ± 6.4 mL/kg/min Pla: 47.5 ± 7.1 mL/kg/min (p < 0.01) Wmax: Int: 325 ± 54.2 W Pla: 274 ± 51.6 W (p < 0.05) RCT |
Sample size calculation was based on changes in exercise-induced Trp levels (86) from baseline to end of 12-wk intervention. Between 10 and 12 subjects per group estimated, depending on SD and effect size, to reach probability of error (alpha/2) of 5 and 80% power. Allowing for a drop-out rate of 30%, 16 subjects per group were recruited. | Ecologic® Performance: Bifidobacterium bifidum W23 Bifidobacterium lactis W51 Enterococcus faecium W54 Lactobacillus acidophilus W22 Lactobacillus brevis W63 Lactococcus lactis W58 1 × 1010 CFU/sachet 1 sachet daily for 12 wk |
No alcohol or fermented dairy products. 3 d food record at baseline and 12 wks. NSBetween groups. Maintained normal training. Weekly training log. Int: 8.0 ± 2.3 h/wk Pla: 6.6 ± 4.3 h/wk (p < 0.001) |
GIS |
| Tavares-Silva et al. (87) |
n = 14 male runners Age: Pla: 38.28 ± 3.09 Int: 41.57 ± 3.20 VO2Peak (kg/mL/min): Pla: 54.53 ± 6.88 Int: 56.92 ± 8.35 RCT |
Not specified | Gelatinous capsules: Lactobacillus acidophilus-LB-G80, Lactobacillus paracasei-LPc-G110, Lactococcus subp. lactis-LLL-G25, Bifidobacterium animalis subp. lactis-BL-G101, Bifidobacterium bifidum-BB-G90 5 × 109 CFU 2.0 g/day, 1 capsule/d, 30 days |
Dietary questionnaire 2x/wk + once on weekends: Kcal, carbohydrates, protein, lipids NSbetween groups. Physical activity not reported. |
Cytokine responses |
| Townsend et al. (88) |
n = 25 male baseball players Age: 20.1 ± 1.5 yrs 1RM Squat (baseline, mean): Int: 116.8 kg, Pla: 133.0 kg Deadlift 1RM (baseline mean): Int: 139.9 kg, Pla: 162.8 kg RCT |
Not specified, however study reported as statistically under-powered to detect modest effects in some biomarkers. | Bacillis subtilis DE111, 1.24 × 109 CFU/cap 1 capsule daily for 12 wk | 3 d food diary on wk 1, 9, 12 NSbetween groups. 12 wk triphasic, undulating, periodized resistance training program | Intestinal permeability Cytokine responses |
| Vaisberg et al. (89) |
n = 42 male runners Age: Int: 39.6 yrs, Pla: 40.1 yrs VO2max (mL/kg/min): Int: 57.64, Pla: 57.86 RCT |
Not specified |
Lactobacillus casei Shirota, 40 × 109 live cells/bottle 1 × 80 ml bottle daily for 30 days |
Dietary control not stated. Instructed to maintain usual training exercise schedule—not reported. | Cytokine responses |
| West et al. (90) |
n = 88 (62M/35F recruited) 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: 53.0 Pla: M: 55.8, F: 51.6 RCT |
A sample size of n = 80 required for identifying substantial changes in the incidence of illness (91). We assumed 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 day food diary. Usual diet, without probiotic foods. Training log kept | Cytokine responses Bacterial taxa GIS |
| Synbiotic studies | |||||
| Coman et al. (92) |
n = 10 (3M/7F), age (range) 20–45 yrs (activity not stated) RCT |
Not specified | Synbiotec S.r.l., Camerino, Italy: L. rhamnosus IMC 501[R] L. paracasei IMC 502[R] plus oat bran fiber 200 ml fermented milk, containing 1 × 109 CFU strain per portion. 200 ml Consumed daily for 4 wk |
Not stated | Bacterial taxa GIS |
| Quero et al. (93) |
n = 27 (14 sedentary males/13 professional male soccer players 2nd Div B level of the Spanish National League Age: Sedentary: Pla: 24.31 ± 3.94, Int: 23.04 ± 2.09 Athletes: Pla: 21.9 ± 2.77, Int: 20.66 ± 1.39 RCT |
Not specified | Gasteel Plus® (Heel España S.A.U laboratories) B. lactis CBP-001010, L. rhamnosus CNCM I-4036, B. longum ES1, Fructooligosaccharides (200 mg) 1.5 mg of zinc, 8.25 μg of selenium, 0.75 μg of vitamin, and maltodextrin as an excipient. 1 stick containing ≥1 × 109 CFU daily for 30 days |
Participants were prohibited from consuming probiotics, prebiotics, or fermented products (yogurt or other foods) and any medications that could interfere with the study protocol Subjects were asked to maintain, 2 weeks before and during the study, their regular lifestyle. |
Cytokine responses |
| Roberts et al. (94) |
n = 20 (18M/2F) long course triathletes Age 35 yrs 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 90 days |
Habitual diet, food diary first and last wk of each month. NS between groups or over intervention time period. Prescribed triathlon training program, individualized. NSBetween groups for training load throughout intervention period. |
Intestinal permeability Endotoxin responses GIS |
| Valle et al. (96) |
n = 65 (39M/26F) Military recruits Age: Int: 19·69 ± 1·25 Pla: 19·5 ± 1·22 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). |
60 g ice cream containing: Lactobacillus acidophilus LA-5, 10.3 log CFU; Bifidobacterium animalis BB−12, 11.0 log CFU 2.3 g of inulin daily for 30 days |
We recommended participants not to consume any foods containing prebiotics and probiotics (e.g., probiotic yogurts, fermented milk) 15 d before the beginning of the research period, particularly over the weekend, when they are released to go home. This consumption was controlled during the week as all food was provided (data not shown). Not stated during the supplementation period however the participants were undergoing training in a military boarding school. |
Bacterial taxa Fecal SCFA GIS |
| West et al. (98) |
N = 22 male cyclists Age: Syn: 34.4 ± 3.5 yrs, Pre: 31.4 ± 4.9 yrs VO2max: Syn: 57.9 ± 7.3 ml/kg/min Pre: 56.4 ± 4.9 ml/kg/min RCT |
Sample size was determined based on variance analysis (standard deviations) from previous studies on the parameters of interest. To demonstrate a difference of 0.20 of the pooled between-subject standard deviation in the salivary immune parameters, which have previously shown the largest variance, a total of nine subjects per group were required to give 80% power at an α level of 0.05. | Synbiotic capsules (Biosource™ Gut Balance, Probiotech Pharma): L. paracasei subs Paracasei (L. casei 431®), 4.6 × 108 per cap Bifidobacterium animalis ssp. lactis (BB-12®), 6 × 108 per cap L. acidophilus LA-5, 4.6 × 108 per cap L. rhamnosus GG, 4.6 × 108 per cap Raftiline, 90 mg per cap Raftilose GR, 10 mg per cap Prebiotic capsules: Acacia powder, 116 mg per cap 3 capsules daily for 3 wk |
14 days run-in, no yogurt or products influencing microbiome. Training log kept: Training load/wk: (duration × intensity) Syn: 21.3 ± 18.5 Pro: 21.4 ± 16.8NS |
Cytokine responses Intestinal permeability Bacterial taxa Fecal SCFA GIS |
RCT, Randomized control trial; RXT, randomized crossover trial; SCFA, short chain fatty acids; wk, weeks; NS, not significant.